""" Python implementation of JSON-LD processor This implementation is ported from the JavaScript implementation of JSON-LD. .. module:: jsonld :synopsis: Python implementation of JSON-LD .. moduleauthor:: Dave Longley .. moduleauthor:: Mike Johnson .. moduleauthor:: Tim McNamara """ __copyright__ = 'Copyright (c) 2011-2014 Digital Bazaar, Inc.' __license__ = 'New BSD license' __version__ = '0.6.8' __all__ = [ 'compact', 'expand', 'flatten', 'frame', 'link', 'from_rdf', 'to_rdf', 'normalize', 'set_document_loader', 'get_document_loader', 'parse_link_header', 'load_document', 'register_rdf_parser', 'unregister_rdf_parser', 'JsonLdProcessor', 'JsonLdError', 'ActiveContextCache'] import copy import hashlib import json import os import posixpath import re import socket import ssl import string import sys import traceback from collections import deque, namedtuple from numbers import Integral, Real from context import getApschemaV1_9 from context import getApschemaV1_21 from context import getLitepubV0_1 from context import getLitepubSocial from context import getV1Schema from context import getV1SecuritySchema from context import getActivitystreamsSchema try: from functools import cmp_to_key except ImportError: def cmp_to_key(mycmp): """ Convert a cmp= function into a key= function Source: http://hg.python.org/cpython/file/default/Lib/functools.py """ class K(object): __slots__ = ['obj'] def __init__(self, obj): self.obj = obj def __lt__(self, other): return mycmp(self.obj, other.obj) < 0 def __gt__(self, other): return mycmp(self.obj, other.obj) > 0 def __eq__(self, other): return mycmp(self.obj, other.obj) == 0 def __le__(self, other): return mycmp(self.obj, other.obj) <= 0 def __ge__(self, other): return mycmp(self.obj, other.obj) >= 0 def __ne__(self, other): return mycmp(self.obj, other.obj) != 0 __hash__ = None return K # support python 2 if sys.version_info[0] >= 3: from urllib.request import HTTPSHandler import urllib.parse as urllib_parse from http.client import HTTPSConnection basestring = str def cmp(a, b): return (a > b) - (a < b) else: from urllib2 import HTTPSHandler import urlparse as urllib_parse from httplib import HTTPSConnection # XSD constants XSD_BOOLEAN = 'http://www.w3.org/2001/XMLSchema#boolean' XSD_DOUBLE = 'http://www.w3.org/2001/XMLSchema#double' XSD_INTEGER = 'http://www.w3.org/2001/XMLSchema#integer' XSD_STRING = 'http://www.w3.org/2001/XMLSchema#string' # RDF constants RDF = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#' RDF_LIST = RDF + 'List' RDF_FIRST = RDF + 'first' RDF_REST = RDF + 'rest' RDF_NIL = RDF + 'nil' RDF_TYPE = RDF + 'type' RDF_LANGSTRING = RDF + 'langString' # JSON-LD keywords KEYWORDS = [ '@base', '@context', '@container', '@default', '@embed', '@explicit', '@graph', '@id', '@index', '@language', '@list', '@omitDefault', '@preserve', '@requireAll', '@reverse', '@set', '@type', '@value', '@vocab'] # JSON-LD link header rel LINK_HEADER_REL = 'http://www.w3.org/ns/json-ld#context' # Restraints MAX_CONTEXT_URLS = 10 def compact(input_, ctx, options=None): """ Performs JSON-LD compaction. :param input_: the JSON-LD input to compact. :param ctx: the JSON-LD context to compact with. :param [options]: the options to use. [base] the base IRI to use. [compactArrays] True to compact arrays to single values when appropriate, False not to (default: True). [graph] True to always output a top-level graph (default: False). [expandContext] a context to expand with. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the compacted JSON-LD output. """ return JsonLdProcessor().compact(input_, ctx, options) def expand(input_, options=None): """ Performs JSON-LD expansion. :param input_: the JSON-LD input to expand. :param [options]: the options to use. [base] the base IRI to use. [expandContext] a context to expand with. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the expanded JSON-LD output. """ return JsonLdProcessor().expand(input_, options) def flatten(input_, ctx=None, options=None): """ Performs JSON-LD flattening. :param input_: the JSON-LD input to flatten. :param ctx: the JSON-LD context to compact with (default: None). :param [options]: the options to use. [base] the base IRI to use. [expandContext] a context to expand with. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the flattened JSON-LD output. """ return JsonLdProcessor().flatten(input_, ctx, options) def frame(input_, frame, options=None): """ Performs JSON-LD framing. :param input_: the JSON-LD input to frame. :param frame: the JSON-LD frame to use. :param [options]: the options to use. [base] the base IRI to use. [expandContext] a context to expand with. [embed] default @embed flag (default: True). [explicit] default @explicit flag (default: False). [requireAll] default @requireAll flag (default: True). [omitDefault] default @omitDefault flag (default: False). [documentLoader(url)] the document loader (default: _default_document_loader). :return: the framed JSON-LD output. """ return JsonLdProcessor().frame(input_, frame, options) def link(input_, ctx, options=None): """ **Experimental** Links a JSON-LD document's nodes in memory. :param input_: the JSON-LD document to link. :param ctx: the JSON-LD context to apply or None. :param [options]: the options to use. [base] the base IRI to use. [expandContext] a context to expand with. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the linked JSON-LD output. """ # API matches running frame with a wildcard frame and embed: '@link' # get arguments frame = {'@embed': '@link'} if ctx: frame['@context'] = ctx frame['@embed'] = '@link' return frame(input, frame, options) def normalize(input_: {}, options=None): """ Performs JSON-LD normalization. :param input_: the JSON-LD input to normalize. :param [options]: the options to use. [base] the base IRI to use. [format] the format if output is a string: 'application/nquads' for N-Quads. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the normalized JSON-LD output. """ return JsonLdProcessor().normalize(input_, options) def from_rdf(input_, options=None): """ Converts an RDF dataset to JSON-LD. :param input_: a serialized string of RDF in a format specified by the format option or an RDF dataset to convert. :param [options]: the options to use: [format] the format if input is a string: 'application/nquads' for N-Quads (default: 'application/nquads'). [useRdfType] True to use rdf:type, False to use @type (default: False). [useNativeTypes] True to convert XSD types into native types (boolean, integer, double), False not to (default: True). :return: the JSON-LD output. """ return JsonLdProcessor().from_rdf(input_, options) def to_rdf(input_, options=None): """ Outputs the RDF dataset found in the given JSON-LD object. :param input_: the JSON-LD input. :param [options]: the options to use. [base] the base IRI to use. [format] the format to use to output a string: 'application/nquads' for N-Quads. [produceGeneralizedRdf] true to output generalized RDF, false to produce only standard RDF (default: false). [documentLoader(url)] the document loader (default: _default_document_loader). :return: the resulting RDF dataset (or a serialization of it). """ return JsonLdProcessor().to_rdf(input_, options) def set_document_loader(load_document): """ Sets the default JSON-LD document loader. :param load_document(url): the document loader to use. """ global _default_document_loader _default_document_loader = load_document def get_document_loader(): """ Gets the default JSON-LD document loader. :return: the default document loader. """ return _default_document_loader def parse_link_header(header): """ Parses a link header. The results will be key'd by the value of "rel". Link: ; \ rel="http://www.w3.org/ns/json-ld#context"; type="application/ld+json" Parses as: { 'http://www.w3.org/ns/json-ld#context': { target: http://json-ld.org/contexts/person.jsonld, type: 'application/ld+json' } } If there is more than one "rel" with the same IRI, then entries in the resulting map for that "rel" will be lists. :param header: the link header to parse. :return: the parsed result. """ rval = {} # split on unbracketed/unquoted commas entries = re.findall(r'(?:<[^>]*?>|"[^"]*?"|[^,])+', header) if not entries: return rval r_link_header = r'\s*<([^>]*?)>\s*(?:;\s*(.*))?' for entry in entries: match = re.search(r_link_header, entry) if not match: continue match = match.groups() result = {'target': match[0]} params = match[1] r_params = r'(.*?)=(?:(?:"([^"]*?)")|([^"]*?))\s*(?:(?:;\s*)|$)' matches = re.findall(r_params, params) for match in matches: result[match[0]] = match[2] if match[1] is None else match[1] rel = result.get('rel', '') if isinstance(rval.get(rel), list): rval[rel].append(result) elif rel in rval: rval[rel] = [rval[rel], result] else: rval[rel] = result return rval def load_document(url): """ Retrieves JSON-LD at the given URL. :param url: the URL to retrieve. :return: the RemoteDocument. """ try: # validate URL pieces = urllib_parse.urlparse(url) if (not all([pieces.scheme, pieces.netloc]) or pieces.scheme not in ['http', 'https', 'dat'] or set(pieces.netloc) > set( string.ascii_letters + string.digits + '-.:')): raise JsonLdError( 'URL could not be dereferenced; only http/https/dat ' 'URLs are supported.', 'jsonld.InvalidUrl', {'url': url}, code='loading document failed') if url == 'https://w3id.org/identity/v1': doc = { 'contextUrl': None, 'documentUrl': url, 'document': getV1Schema() } return doc if url == 'https://w3id.org/security/v1': doc = { 'contextUrl': None, 'documentUrl': url, 'document': getV1SecuritySchema() } return doc elif url == 'https://www.w3.org/ns/activitystreams': doc = { 'contextUrl': None, 'documentUrl': url, 'document': getActivitystreamsSchema() } return doc elif url.endswith('/apschema/v1.9'): doc = { 'contextUrl': None, 'documentUrl': url, 'document': getApschemaV1_9() } return doc elif url.endswith('/apschema/v1.21'): doc = { 'contextUrl': None, 'documentUrl': url, 'document': getApschemaV1_21() } return doc elif url.endswith('/litepub-0.1.jsonld'): doc = { 'contextUrl': None, 'documentUrl': url, 'document': getLitepubV0_1() } return doc elif url == 'https://litepub.social/litepub/context.jsonld': doc = { 'contextUrl': None, 'documentUrl': url, 'document': getLitepubSocial() } return doc return None except JsonLdError as e: raise e except Exception as cause: raise JsonLdError( 'Could not retrieve a JSON-LD document from the URL.', 'jsonld.LoadDocumentError', code='loading document failed', cause=cause) def register_rdf_parser(content_type, parser): """ Registers a global RDF parser by content-type, for use with from_rdf. Global parsers will be used by JsonLdProcessors that do not register their own parsers. :param content_type: the content-type for the parser. :param parser(input): the parser function (takes a string as a parameter and returns an RDF dataset). """ global _rdf_parsers _rdf_parsers[content_type] = parser def unregister_rdf_parser(content_type): """ Unregisters a global RDF parser by content-type. :param content_type: the content-type for the parser. """ global _rdf_parsers if content_type in _rdf_parsers: del _rdf_parsers[content_type] def prepend_base(base, iri): """ Prepends a base IRI to the given relative IRI. :param base: the base IRI. :param iri: the relative IRI. :return: the absolute IRI. """ # skip IRI processing if base is None: return iri # already an absolute iri if _is_absolute_iri(iri): return iri # parse IRIs base = parse_url(base) rel = parse_url(iri) # per RFC3986 5.2.2 transform = { 'scheme': base.scheme } if rel.authority is not None: transform['authority'] = rel.authority transform['path'] = rel.path transform['query'] = rel.query else: transform['authority'] = base.authority if rel.path == '': transform['path'] = base.path if rel.query is not None: transform['query'] = rel.query else: transform['query'] = base.query else: if rel.path.startswith('/'): # IRI represents an absolute path transform['path'] = rel.path else: # merge paths path = base.path # append relative path to the end of the last # directory from base if rel.path != '': path = path[0:path.rfind('/') + 1] if len(path) > 0 and not path.endswith('/'): path += '/' path += rel.path transform['path'] = path transform['query'] = rel.query # normalize path path = transform['path'] add_slash = path.endswith('/') path = posixpath.normpath(path) if not path.endswith('/') and add_slash: path += '/' # do not include '.' path if path == '.': path = '' transform['path'] = path transform['fragment'] = rel.fragment # construct URL rval = unparse_url(transform) # handle empty base case if rval == '': rval = './' return rval def remove_base(base, iri): """ Removes a base IRI from the given absolute IRI. :param base: the base IRI. :param iri: the absolute IRI. :return: the relative IRI if relative to base, otherwise the absolute IRI. """ # skip IRI processing if base is None: return iri base = parse_url(base) rel = parse_url(iri) # schemes and network locations (authorities) don't match, don't alter IRI if not (base.scheme == rel.scheme and base.authority == rel.authority): return iri path = posixpath.relpath(rel.path, base.path) if rel.path else '' path = posixpath.normpath(path) # workaround a relpath bug in Python 2.6 (http://bugs.python.org/issue5117) if base.path == '/' and path.startswith('../'): path = path[3:] if path == '.' and not rel.path.endswith('/') and not ( rel.query or rel.fragment): path = posixpath.basename(rel.path) if rel.path.endswith('/') and not path.endswith('/'): path += '/' # adjustments for base that is not a directory if not base.path.endswith('/'): if path.startswith('../'): path = path[3:] elif path.startswith('./'): path = path[2:] elif path.startswith('.'): path = path[1:] return unparse_url((None, None, path, rel.query, rel.fragment)) or './' ParsedUrl = namedtuple( 'ParsedUrl', ['scheme', 'authority', 'path', 'query', 'fragment']) def parse_url(url): # regex from RFC 3986 p = r'^(?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*)(?:\?([^#]*))?(?:#(.*))?' m = re.match(p, url) return ParsedUrl(*m.groups()) def unparse_url(parsed): if isinstance(parsed, dict): parsed = ParsedUrl(**parsed) elif isinstance(parsed, list) or isinstance(parsed, tuple): parsed = ParsedUrl(*parsed) rval = '' if parsed.scheme: rval += parsed.scheme + ':' if parsed.authority is not None: rval += '//' + parsed.authority rval += parsed.path if parsed.query is not None: rval += '?' + parsed.query if parsed.fragment is not None: rval += '#' + parsed.fragment return rval # The default JSON-LD document loader. _default_document_loader = load_document # Registered global RDF parsers hashed by content-type. _rdf_parsers = {} class JsonLdProcessor(object): """ A JSON-LD processor. """ def __init__(self): """ Initialize the JSON-LD processor. """ # processor-specific RDF parsers self.rdf_parsers = None def compact(self, input_, ctx, options): """ Performs JSON-LD compaction. :param input_: the JSON-LD input to compact. :param ctx: the context to compact with. :param options: the options to use. [base] the base IRI to use. [compactArrays] True to compact arrays to single values when appropriate, False not to (default: True). [graph] True to always output a top-level graph (default: False). [expandContext] a context to expand with. [skipExpansion] True to assume the input is expanded and skip expansion, False not to, (default: False). [activeCtx] True to also return the active context used. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the compacted JSON-LD output. """ if ctx is None: raise JsonLdError( 'The compaction context must not be null.', 'jsonld.CompactError', code='invalid local context') # nothing to compact if input_ is None: return None # set default options options = options or {} options.setdefault('base', input_ if _is_string(input_) else '') options.setdefault('compactArrays', True) options.setdefault('graph', False) options.setdefault('skipExpansion', False) options.setdefault('activeCtx', False) options.setdefault('documentLoader', _default_document_loader) options.setdefault('link', False) if options['link']: # force skip expansion when linking, "link" is not part of the # public API, it should only be called from framing options['skipExpansion'] = True if options['skipExpansion']: expanded = input_ else: # expand input try: expanded = self.expand(input_, options) except JsonLdError as cause: raise JsonLdError( 'Could not expand input before compaction.', 'jsonld.CompactError', cause=cause) # process context active_ctx = self._get_initial_context(options) try: active_ctx = self.process_context(active_ctx, ctx, options) except JsonLdError as cause: raise JsonLdError( 'Could not process context before compaction.', 'jsonld.CompactError', cause=cause) # do compaction compacted = self._compact(active_ctx, None, expanded, options) if (options['compactArrays'] and not options['graph'] and _is_array(compacted)): # simplify to a single item if len(compacted) == 1: compacted = compacted[0] # simplify to an empty object elif len(compacted) == 0: compacted = {} # always use an array if graph options is on elif options['graph']: compacted = JsonLdProcessor.arrayify(compacted) # follow @context key if _is_object(ctx) and '@context' in ctx: ctx = ctx['@context'] # build output context ctx = copy.deepcopy(ctx) ctx = JsonLdProcessor.arrayify(ctx) # remove empty contexts tmp = ctx ctx = [] for v in tmp: if not _is_object(v) or len(v) > 0: ctx.append(v) # remove array if only one context ctx_length = len(ctx) has_context = (ctx_length > 0) if ctx_length == 1: ctx = ctx[0] # add context and/or @graph if _is_array(compacted): # use '@graph' keyword kwgraph = self._compact_iri(active_ctx, '@graph') graph = compacted compacted = {} if has_context: compacted['@context'] = ctx compacted[kwgraph] = graph elif _is_object(compacted) and has_context: # reorder keys so @context is first graph = compacted compacted = {} compacted['@context'] = ctx for k, v in graph.items(): compacted[k] = v if options['activeCtx']: return {'compacted': compacted, 'activeCtx': active_ctx} else: return compacted def expand(self, input_, options): """ Performs JSON-LD expansion. :param input_: the JSON-LD input to expand. :param options: the options to use. [base] the base IRI to use. [expandContext] a context to expand with. [keepFreeFloatingNodes] True to keep free-floating nodes, False not to (default: False). [documentLoader(url)] the document loader (default: _default_document_loader). :return: the expanded JSON-LD output. """ # set default options options = options or {} options.setdefault('keepFreeFloatingNodes', False) options.setdefault('documentLoader', _default_document_loader) # if input is a string, attempt to dereference remote document if _is_string(input_): remote_doc = options['documentLoader'](input_) else: remote_doc = { 'contextUrl': None, 'documentUrl': None, 'document': input_ } try: if remote_doc['document'] is None: raise JsonLdError( 'No remote document found at the given URL.', 'jsonld.NullRemoteDocument') if _is_string(remote_doc['document']): remote_doc['document'] = json.loads(remote_doc['document']) except Exception as cause: raise JsonLdError( 'Could not retrieve a JSON-LD document from the URL.', 'jsonld.LoadDocumentError', {'remoteDoc': remote_doc}, code='loading document failed', cause=cause) # set default base options.setdefault('base', remote_doc['documentUrl'] or '') # build meta-object and retrieve all @context urls input_ = { 'document': copy.deepcopy(remote_doc['document']), 'remoteContext': {'@context': remote_doc['contextUrl']} } if 'expandContext' in options: expand_context = copy.deepcopy(options['expandContext']) if _is_object(expand_context) and '@context' in expand_context: input_['expandContext'] = expand_context else: input_['expandContext'] = {'@context': expand_context} try: self._retrieve_context_urls( input_, {}, options['documentLoader'], options['base']) except Exception as cause: raise JsonLdError( 'Could not perform JSON-LD expansion.', 'jsonld.ExpandError', cause=cause) active_ctx = self._get_initial_context(options) document = input_['document'] remote_context = input_['remoteContext']['@context'] # process optional expandContext if 'expandContext' in input_: active_ctx = self.process_context( active_ctx, input_['expandContext']['@context'], options) # process remote context from HTTP Link Header if remote_context is not None: active_ctx = self.process_context( active_ctx, remote_context, options) # do expansion expanded = self._expand(active_ctx, None, document, options, False) # optimize away @graph with no other properties if (_is_object(expanded) and '@graph' in expanded and len(expanded) == 1): expanded = expanded['@graph'] elif expanded is None: expanded = [] # normalize to an array return JsonLdProcessor.arrayify(expanded) def flatten(self, input_, ctx, options): """ Performs JSON-LD flattening. :param input_: the JSON-LD input to flatten. :param ctx: the JSON-LD context to compact with (default: None). :param options: the options to use. [base] the base IRI to use. [expandContext] a context to expand with. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the flattened JSON-LD output. """ options = options or {} options.setdefault('base', input_ if _is_string(input_) else '') options.setdefault('documentLoader', _default_document_loader) try: # expand input expanded = self.expand(input_, options) except Exception as cause: raise JsonLdError( 'Could not expand input before flattening.', 'jsonld.FlattenError', cause=cause) # do flattening flattened = self._flatten(expanded) if ctx is None: return flattened # compact result (force @graph option to true, skip expansion) options['graph'] = True options['skipExpansion'] = True try: compacted = self.compact(flattened, ctx, options) except Exception as cause: raise JsonLdError( 'Could not compact flattened output.', 'jsonld.FlattenError', cause=cause) return compacted def frame(self, input_, frame, options): """ Performs JSON-LD framing. :param input_: the JSON-LD object to frame. :param frame: the JSON-LD frame to use. :param options: the options to use. [base] the base IRI to use. [expandContext] a context to expand with. [embed] default @embed flag: '@last', '@always', '@never', '@link' (default: '@last'). [explicit] default @explicit flag (default: False). [requireAll] default @requireAll flag (default: True). [omitDefault] default @omitDefault flag (default: False). [documentLoader(url)] the document loader (default: _default_document_loader). :return: the framed JSON-LD output. """ # set default options options = options or {} options.setdefault('base', input_ if _is_string(input_) else '') options.setdefault('compactArrays', True) options.setdefault('embed', '@last') options.setdefault('explicit', False) options.setdefault('requireAll', True) options.setdefault('omitDefault', False) options.setdefault('documentLoader', _default_document_loader) # if frame is a string, attempt to dereference remote document if _is_string(frame): remote_frame = options['documentLoader'](frame) else: remote_frame = { 'contextUrl': None, 'documentUrl': None, 'document': frame } try: if remote_frame['document'] is None: raise JsonLdError( 'No remote document found at the given URL.', 'jsonld.NullRemoteDocument') if _is_string(remote_frame['document']): remote_frame['document'] = json.loads(remote_frame['document']) except Exception as cause: raise JsonLdError( 'Could not retrieve a JSON-LD document from the URL.', 'jsonld.LoadDocumentError', {'remoteDoc': remote_frame}, code='loading document failed', cause=cause) # preserve frame context frame = remote_frame['document'] if frame is not None: ctx = frame.get('@context', {}) if remote_frame['contextUrl'] is not None: if ctx is not None: ctx = remote_frame['contextUrl'] else: ctx = JsonLdProcessor.arrayify(ctx) ctx.append(remote_frame['contextUrl']) frame['@context'] = ctx try: # expand input expanded = self.expand(input_, options) except JsonLdError as cause: raise JsonLdError( 'Could not expand input before framing.', 'jsonld.FrameError', cause=cause) try: # expand frame opts = copy.deepcopy(options) opts['keepFreeFloatingNodes'] = True expanded_frame = self.expand(frame, opts) except JsonLdError as cause: raise JsonLdError( 'Could not expand frame before framing.', 'jsonld.FrameError', cause=cause) # do framing framed = self._frame(expanded, expanded_frame, options) try: # compact result (force @graph option to True, skip expansion, # check for linked embeds) options['graph'] = True options['skipExpansion'] = True options['link'] = {} options['activeCtx'] = True result = self.compact(framed, ctx, options) except JsonLdError as cause: raise JsonLdError( 'Could not compact framed output.', 'jsonld.FrameError', cause=cause) compacted = result['compacted'] active_ctx = result['activeCtx'] # get graph alias graph = self._compact_iri(active_ctx, '@graph') # remove @preserve from results compacted[graph] = self._remove_preserve( active_ctx, compacted[graph], options) return compacted def normalize(self, input_, options): """ Performs RDF normalization on the given JSON-LD input. :param input_: the JSON-LD input to normalize. :param options: the options to use. [base] the base IRI to use. [format] the format if output is a string: 'application/nquads' for N-Quads. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the normalized output. """ # set default options options = options or {} options.setdefault('base', input_ if _is_string(input_) else '') options.setdefault('documentLoader', _default_document_loader) try: # convert to RDF dataset then do normalization opts = copy.deepcopy(options) if 'format' in opts: del opts['format'] opts['produceGeneralizedRdf'] = False dataset = self.to_rdf(input_, opts) except JsonLdError as cause: raise JsonLdError( 'Could not convert input to RDF dataset before normalization.', 'jsonld.NormalizeError', cause=cause) # do normalization return self._normalize(dataset, options) def from_rdf(self, dataset, options): """ Converts an RDF dataset to JSON-LD. :param dataset: a serialized string of RDF in a format specified by the format option or an RDF dataset to convert. :param options: the options to use. [format] the format if input is a string: 'application/nquads' for N-Quads (default: 'application/nquads'). [useRdfType] True to use rdf:type, False to use @type (default: False). [useNativeTypes] True to convert XSD types into native types (boolean, integer, double), False not to (default: False). :return: the JSON-LD output. """ global _rdf_parsers # set default options options = options or {} options.setdefault('useRdfType', False) options.setdefault('useNativeTypes', False) if ('format' not in options) and _is_string(dataset): options['format'] = 'application/nquads' # handle special format if 'format' in options: # supported formats (processor-specific and global) if ((self.rdf_parsers is not None and not options['format'] in self.rdf_parsers) or (self.rdf_parsers is None and not options['format'] in _rdf_parsers)): raise JsonLdError( 'Unknown input format.', 'jsonld.UnknownFormat', {'format': options['format']}) if self.rdf_parsers is not None: parser = self.rdf_parsers[options['format']] else: parser = _rdf_parsers[options['format']] dataset = parser(dataset) # convert from RDF return self._from_rdf(dataset, options) def to_rdf(self, input_, options): """ Outputs the RDF dataset found in the given JSON-LD object. :param input_: the JSON-LD input. :param options: the options to use. [base] the base IRI to use. [format] the format if input is a string: 'application/nquads' for N-Quads. [produceGeneralizedRdf] true to output generalized RDF, false to produce only standard RDF (default: false). [documentLoader(url)] the document loader (default: _default_document_loader). :return: the resulting RDF dataset (or a serialization of it). """ # set default options options = options or {} options.setdefault('base', input_ if _is_string(input_) else '') options.setdefault('produceGeneralizedRdf', False) options.setdefault('documentLoader', _default_document_loader) try: # expand input expanded = self.expand(input_, options) except JsonLdError as cause: raise JsonLdError( 'Could not expand input before serialization to ' 'RDF.', 'jsonld.RdfError', cause=cause) # create node map for default graph (and any named graphs) namer = UniqueNamer('_:b') node_map = {'@default': {}} self._create_node_map(expanded, node_map, '@default', namer) # output RDF dataset dataset = {} for graph_name, graph in sorted(node_map.items()): # skip relative IRIs if graph_name == '@default' or _is_absolute_iri(graph_name): dataset[graph_name] = self._graph_to_rdf(graph, namer, options) # convert to output format if 'format' in options: if options['format'] == 'application/nquads': return self.to_nquads(dataset) raise JsonLdError( 'Unknown output format.', 'jsonld.UnknownFormat', {'format': options['format']}) return dataset def process_context(self, active_ctx, local_ctx, options): """ Processes a local context, retrieving any URLs as necessary, and returns a new active context in its callback. :param active_ctx: the current active context. :param local_ctx: the local context to process. :param options: the options to use. [documentLoader(url)] the document loader (default: _default_document_loader). :return: the new active context. """ # return initial context early for None context if local_ctx is None: return self._get_initial_context(options) # set default options options = options or {} options.setdefault('base', '') options.setdefault('documentLoader', _default_document_loader) # retrieve URLs in local_ctx local_ctx = copy.deepcopy(local_ctx) if (_is_string(local_ctx) or ( _is_object(local_ctx) and '@context' not in local_ctx)): local_ctx = {'@context': local_ctx} try: self._retrieve_context_urls( local_ctx, {}, options['documentLoader'], options['base']) except Exception as cause: raise JsonLdError( 'Could not process JSON-LD context.', 'jsonld.ContextError', cause=cause) # process context return self._process_context(active_ctx, local_ctx, options) def register_rdf_parser(self, content_type, parser): """ Registers a processor-specific RDF parser by content-type. Global parsers will no longer be used by this processor. :param content_type: the content-type for the parser. :param parser(input): the parser function (takes a string as a parameter and returns an RDF dataset). """ if self.rdf_parsers is None: self.rdf_parsers = {} self.rdf_parsers[content_type] = parser def unregister_rdf_parser(self, content_type): """ Unregisters a process-specific RDF parser by content-type. If there are no remaining processor-specific parsers, then the global parsers will be re-enabled. :param content_type: the content-type for the parser. """ if (self.rdf_parsers is not None and content_type in self.rdf_parsers): del self.rdf_parsers[content_type] if len(self.rdf_parsers) == 0: self.rdf_parsers = None @staticmethod def has_property(subject, property): """ Returns True if the given subject has the given property. :param subject: the subject to check. :param property: the property to look for. :return: True if the subject has the given property, False if not. """ if property in subject: value = subject[property] return not _is_array(value) or len(value) > 0 return False @staticmethod def has_value(subject, property, value): """ Determines if the given value is a property of the given subject. :param subject: the subject to check. :param property: the property to check. :param value: the value to check. :return: True if the value exists, False if not. """ if JsonLdProcessor.has_property(subject, property): val = subject[property] is_list = _is_list(val) if _is_array(val) or is_list: if is_list: val = val['@list'] for v in val: if JsonLdProcessor.compare_values(value, v): return True # avoid matching the set of values with an array value parameter elif not _is_array(value): return JsonLdProcessor.compare_values(value, val) return False @staticmethod def add_value(subject, property, value, options={}): """ Adds a value to a subject. If the value is an array, all values in the array will be added. :param subject: the subject to add the value to. :param property: the property that relates the value to the subject. :param value: the value to add. :param [options]: the options to use: [propertyIsArray] True if the property is always an array, False if not (default: False). [allowDuplicate] True to allow duplicates, False not to (uses a simple shallow comparison of subject ID or value) (default: True). """ options.setdefault('propertyIsArray', False) options.setdefault('allowDuplicate', True) if _is_array(value): if (len(value) == 0 and options['propertyIsArray'] and property not in subject): subject[property] = [] for v in value: JsonLdProcessor.add_value(subject, property, v, options) elif property in subject: # check if subject already has value if duplicates not allowed has_value = \ (not options['allowDuplicate'] and JsonLdProcessor.has_value(subject, property, value)) # make property an array if value not present or always an array if (not _is_array(subject[property]) and (not has_value or options['propertyIsArray'])): subject[property] = [subject[property]] # add new value if not has_value: subject[property].append(value) else: # add new value as set or single value subject[property] = ( [value] if options['propertyIsArray'] else value) @staticmethod def get_values(subject, property): """ Gets all of the values for a subject's property as an array. :param subject: the subject. :param property: the property. :return: all of the values for a subject's property as an array. """ return JsonLdProcessor.arrayify(subject.get(property) or []) @staticmethod def remove_property(subject, property): """ Removes a property from a subject. :param subject: the subject. :param property: the property. """ del subject[property] @staticmethod def remove_value(subject, property, value, options={}): """ Removes a value from a subject. :param subject: the subject. :param property: the property that relates the value to the subject. :param value: the value to remove. :param [options]: the options to use: [propertyIsArray]: True if the property is always an array, False if not (default: False). """ options.setdefault('propertyIsArray', False) # filter out value def filter_value(e): return not JsonLdProcessor.compare_values(e, value) values = JsonLdProcessor.get_values(subject, property) values = list(filter(filter_value, values)) if len(values) == 0: JsonLdProcessor.remove_property(subject, property) elif len(values) == 1 and not options['propertyIsArray']: subject[property] = values[0] else: subject[property] = values @staticmethod def compare_values(v1, v2): """ Compares two JSON-LD values for equality. Two JSON-LD values will be considered equal if: 1. They are both primitives of the same type and value. 2. They are both @values with the same @value, @type, @language, and @index, OR 3. They both have @ids that are the same. :param v1: the first value. :param v2: the second value. :return: True if v1 and v2 are considered equal, False if not. """ # 1. equal primitives if not _is_object(v1) and not _is_object(v2) and v1 == v2: type1 = type(v1) type2 = type(v2) if type1 == bool or type2 == bool: return type1 == type2 return True # 2. equal @values if (_is_value(v1) and _is_value(v2) and v1['@value'] == v2['@value'] and v1.get('@type') == v2.get('@type') and v1.get('@language') == v2.get('@language') and v1.get('@index') == v2.get('@index')): type1 = type(v1['@value']) type2 = type(v2['@value']) if type1 == bool or type2 == bool: return type1 == type2 return True # 3. equal @ids if (_is_object(v1) and '@id' in v1 and _is_object(v2) and '@id' in v2): return v1['@id'] == v2['@id'] return False @staticmethod def get_context_value(ctx, key, type_): """ Gets the value for the given active context key and type, None if none is set. :param ctx: the active context. :param key: the context key. :param [type_]: the type of value to get (eg: '@id', '@type'), if not specified gets the entire entry for a key, None if not found. :return: mixed the value. """ rval = None # return None for invalid key if key is None: return rval # get default language if type_ == '@language' and type_ in ctx: rval = ctx[type_] # get specific entry information if key in ctx['mappings']: entry = ctx['mappings'][key] if entry is None: return None # return whole entry if type_ is None: rval = entry # return entry value for type elif type_ in entry: rval = entry[type_] return rval @staticmethod def parse_nquads(input_): """ Parses RDF in the form of N-Quads. :param input_: the N-Quads input to parse. :return: an RDF dataset. """ # define partial regexes iri = '(?:<([^:]+:[^>]*)>)' bnode = '(_:(?:[A-Za-z][A-Za-z0-9]*))' plain = '"([^"\\\\]*(?:\\\\.[^"\\\\]*)*)"' datatype = '(?:\\^\\^' + iri + ')' language = '(?:@([a-z]+(?:-[a-z0-9]+)*))' literal = '(?:' + plain + '(?:' + datatype + '|' + language + ')?)' ws = '[ \\t]+' wso = '[ \\t]*' eoln = r'(?:\r\n)|(?:\n)|(?:\r)' empty = r'^' + wso + '$' # define quad part regexes subject = '(?:' + iri + '|' + bnode + ')' + ws property = iri + ws object = '(?:' + iri + '|' + bnode + '|' + literal + ')' + wso graph = '(?:\\.|(?:(?:' + iri + '|' + bnode + ')' + wso + '\\.))' # Note: Notice that the graph position does not include literals # even though they are specified as a possible value in the # N-Quads note (http://sw.deri.org/2008/07/n-quads/). This is # intentional, as literals in that position are not supported by the # RDF data model or the JSON-LD data model. # See: https://github.com/digitalbazaar/pyld/pull/19 # full quad regex quad = r'^' + wso + subject + property + object + graph + wso + '$' # build RDF dataset dataset = {} # split N-Quad input into lines lines = re.split(eoln, input_) line_number = 0 for line in lines: line_number += 1 # skip empty lines if re.search(empty, line) is not None: continue # parse quad match = re.search(quad, line) if match is None: raise JsonLdError( 'Error while parsing N-Quads invalid quad.', 'jsonld.ParseError', {'line': line_number}) match = match.groups() # create RDF triple triple = {'subject': {}, 'predicate': {}, 'object': {}} # get subject if match[0] is not None: triple['subject'] = {'type': 'IRI', 'value': match[0]} else: triple['subject'] = {'type': 'blank node', 'value': match[1]} # get predicate triple['predicate'] = {'type': 'IRI', 'value': match[2]} # get object if match[3] is not None: triple['object'] = {'type': 'IRI', 'value': match[3]} elif match[4] is not None: triple['object'] = {'type': 'blank node', 'value': match[4]} else: triple['object'] = {'type': 'literal'} replacements = { '\\"': '\"', '\\t': '\t', '\\n': '\n', '\\r': '\r', '\\\\': '\\' } unescaped = match[5] for match, repl in replacements.items(): unescaped = unescaped.replace(match, repl) if match[6] is not None: triple['object']['datatype'] = match[6] elif match[7] is not None: triple['object']['datatype'] = RDF_LANGSTRING triple['object']['language'] = match[7] else: triple['object']['datatype'] = XSD_STRING triple['object']['value'] = unescaped # get graph name ('@default' is used for the default graph) name = '@default' if match[8] is not None: name = match[8] elif match[9] is not None: name = match[9] # initialize graph in dataset if name not in dataset: dataset[name] = [triple] # add triple if unique to its graph else: unique = True triples = dataset[name] for t in dataset[name]: if JsonLdProcessor._compare_rdf_triples(t, triple): unique = False break if unique: triples.append(triple) return dataset @staticmethod def to_nquads(dataset): """ Converts an RDF dataset to N-Quads. :param dataset: the RDF dataset to convert. :return: the N-Quads string. """ quads = [] for graph_name, triples in dataset.items(): for triple in triples: if graph_name == '@default': graph_name = None quads.append(JsonLdProcessor.to_nquad(triple, graph_name)) quads.sort() return ''.join(quads) @staticmethod def to_nquad(triple, graph_name, bnode=None): """ Converts an RDF triple and graph name to an N-Quad string (a single quad). :param triple: the RDF triple to convert. :param graph_name: the name of the graph containing the triple, None for the default graph. :param bnode: the bnode the quad is mapped to (optional, for use during normalization only). :return: the N-Quad string. """ s = triple['subject'] p = triple['predicate'] o = triple['object'] g = graph_name quad = '' # subject is an IRI if s['type'] == 'IRI': quad += '<' + s['value'] + '>' # bnode normalization mode elif bnode is not None: quad += '_:a' if s['value'] == bnode else '_:z' # bnode normal mode else: quad += s['value'] quad += ' ' # property is an IRI if p['type'] == 'IRI': quad += '<' + p['value'] + '>' # FIXME: TBD what to do with bnode predicates during normalization # bnode normalization mode elif bnode is not None: quad += '_:p' # bnode normal mode else: quad += p['value'] quad += ' ' # object is IRI, bnode, or literal if o['type'] == 'IRI': quad += '<' + o['value'] + '>' elif(o['type'] == 'blank node'): # normalization mode if bnode is not None: quad += '_:a' if o['value'] == bnode else '_:z' # normal mode else: quad += o['value'] else: replacements = { '\\': '\\\\', '\t': '\\t', '\n': '\\n', '\r': '\\r', '\"': '\\"' } escaped = o['value'] for match, repl in replacements.items(): escaped = escaped.replace(match, repl) quad += '"' + escaped + '"' if o['datatype'] == RDF_LANGSTRING: if o['language']: quad += '@' + o['language'] elif o['datatype'] != XSD_STRING: quad += '^^<' + o['datatype'] + '>' # graph if g is not None: if not g.startswith('_:'): quad += ' <' + g + '>' elif bnode is not None: quad += ' _:g' else: quad += ' ' + g quad += ' .\n' return quad @staticmethod def arrayify(value): """ If value is an array, returns value, otherwise returns an array containing value as the only element. :param value: the value. :return: an array. """ return value if _is_array(value) else [value] @staticmethod def _compare_rdf_triples(t1, t2): """ Compares two RDF triples for equality. :param t1: the first triple. :param t2: the second triple. :return: True if the triples are the same, False if not. """ for attr in ['subject', 'predicate', 'object']: if(t1[attr]['type'] != t2[attr]['type'] or t1[attr]['value'] != t2[attr]['value']): return False if t1['object'].get('language') != t2['object'].get('language'): return False if t1['object'].get('datatype') != t2['object'].get('datatype'): return False return True def _compact(self, active_ctx, active_property, element, options): """ Recursively compacts an element using the given active context. All values must be in expanded form before this method is called. :param active_ctx: the active context to use. :param active_property: the compacted property with the element to compact, None for none. :param element: the element to compact. :param options: the compaction options. :return: the compacted value. """ # recursively compact array if _is_array(element): rval = [] for e in element: # compact, dropping any None values e = self._compact(active_ctx, active_property, e, options) if e is not None: rval.append(e) if options['compactArrays'] and len(rval) == 1: # use single element if no container is specified container = JsonLdProcessor.get_context_value( active_ctx, active_property, '@container') if container is None: rval = rval[0] return rval # recursively compact object if _is_object(element): if(options['link'] and '@id' in element and element['@id'] in options['link']): # check for a linked element to reuse linked = options['link'][element['@id']] for link in linked: if link['expanded'] == element: return link['compacted'] # do value compaction on @values and subject references if _is_value(element) or _is_subject_reference(element): rval = self._compact_value( active_ctx, active_property, element) if options['link'] and _is_subject_reference(element): # store linked element options['link'].setdefault(element['@id'], []).append( {'expanded': element, 'compacted': rval}) return rval # FIXME: avoid misuse of active property as an expanded property? inside_reverse = (active_property == '@reverse') rval = {} if options['link'] and '@id' in element: # store linked element options['link'].setdefault(element['@id'], []).append( {'expanded': element, 'compacted': rval}) # recursively process element keys in order for expanded_property, expanded_value in sorted(element.items()): # compact @id and @type(s) if expanded_property == '@id' or expanded_property == '@type': # compact single @id if _is_string(expanded_value): compacted_value = self._compact_iri( active_ctx, expanded_value, vocab=(expanded_property == '@type')) # expanded value must be a @type array else: compacted_value = [] for ev in expanded_value: compacted_value.append(self._compact_iri( active_ctx, ev, vocab=True)) # use keyword alias and add value alias = self._compact_iri(active_ctx, expanded_property) is_array = (_is_array(compacted_value) and len(compacted_value) == 0) JsonLdProcessor.add_value( rval, alias, compacted_value, {'propertyIsArray': is_array}) continue # handle @reverse if expanded_property == '@reverse': # recursively compact expanded value compacted_value = self._compact( active_ctx, '@reverse', expanded_value, options) # handle double-reversed properties for compacted_property, value in \ list(compacted_value.items()): mapping = active_ctx['mappings'].get( compacted_property) if mapping and mapping['reverse']: container = JsonLdProcessor.get_context_value( active_ctx, compacted_property, '@container') use_array = (container == '@set' or not options['compactArrays']) JsonLdProcessor.add_value( rval, compacted_property, value, {'propertyIsArray': use_array}) del compacted_value[compacted_property] if len(compacted_value.keys()) > 0: # use keyword alias and add value alias = self._compact_iri( active_ctx, expanded_property) JsonLdProcessor.add_value(rval, alias, compacted_value) continue # handle @index if expanded_property == '@index': # drop @index if inside an @index container container = JsonLdProcessor.get_context_value( active_ctx, active_property, '@container') if container == '@index': continue # use keyword alias and add value alias = self._compact_iri(active_ctx, expanded_property) JsonLdProcessor.add_value(rval, alias, expanded_value) continue # skip array processing for keywords that aren't # @graph or @list if(expanded_property != '@graph' and expanded_property != '@list' and _is_keyword(expanded_property)): # use keyword alias and add value as is alias = self._compact_iri(active_ctx, expanded_property) JsonLdProcessor.add_value(rval, alias, expanded_value) continue # Note: expanded value must be an array due to expansion # algorithm. # preserve empty arrays if len(expanded_value) == 0: item_active_property = self._compact_iri( active_ctx, expanded_property, expanded_value, vocab=True, reverse=inside_reverse) JsonLdProcessor.add_value( rval, item_active_property, [], {'propertyIsArray': True}) # recusively process array values for expanded_item in expanded_value: # compact property and get container type item_active_property = self._compact_iri( active_ctx, expanded_property, expanded_item, vocab=True, reverse=inside_reverse) container = JsonLdProcessor.get_context_value( active_ctx, item_active_property, '@container') # get @list value if appropriate is_list = _is_list(expanded_item) list_ = None if is_list: list_ = expanded_item['@list'] # recursively compact expanded item compacted_item = self._compact( active_ctx, item_active_property, list_ if is_list else expanded_item, options) # handle @list if is_list: # ensure @list is an array compacted_item = JsonLdProcessor.arrayify( compacted_item) if container != '@list': # wrap using @list alias wrapper = {} wrapper[self._compact_iri( active_ctx, '@list')] = compacted_item compacted_item = wrapper # include @index from expanded @list, if any if '@index' in expanded_item: alias = self._compact_iri(active_ctx, '@index') compacted_item[alias] = ( expanded_item['@index']) # can't use @list container for more than 1 list elif item_active_property in rval: raise JsonLdError( 'JSON-LD compact error; property has a ' '"@list" @container rule but there is more ' 'than a single @list that matches the ' 'compacted term in the document. Compaction ' 'might mix unwanted items into the list.', 'jsonld.SyntaxError', code='compaction to list of lists') # handle language and index maps if container == '@language' or container == '@index': # get or create the map object map_object = rval.setdefault(item_active_property, {}) # if container is a language map, simplify compacted # value to a simple string if (container == '@language' and _is_value(compacted_item)): compacted_item = compacted_item['@value'] # add compact value to map object using key from # expanded value based on the container type JsonLdProcessor.add_value( map_object, expanded_item[container], compacted_item) else: # use an array if compactArrays flag is false, # @container is @set or @list, value is an empty # array, or key is @graph is_array = (not options['compactArrays'] or container == '@set' or container == '@list' or (_is_array(compacted_item) and len(compacted_item) == 0) or expanded_property == '@list' or expanded_property == '@graph') # add compact value JsonLdProcessor.add_value( rval, item_active_property, compacted_item, {'propertyIsArray': is_array}) return rval # only primitives remain which are already compact return element def _expand( self, active_ctx, active_property, element, options, inside_list): """ Recursively expands an element using the given context. Any context in the element will be removed. All context URLs must have been retrieved before calling this method. :param active_ctx: the context to use. :param active_property: the property for the element, None for none. :param element: the element to expand. :param options: the expansion options. :param inside_list: True if the property is a list, False if not. :return: the expanded value. """ # nothing to expand if element is None: return element # recursively expand array if _is_array(element): rval = [] container = JsonLdProcessor.get_context_value( active_ctx, active_property, '@container') inside_list = inside_list or container == '@list' for e in element: # expand element e = self._expand( active_ctx, active_property, e, options, inside_list) if inside_list and (_is_array(e) or _is_list(e)): # lists of lists are illegal raise JsonLdError( 'Invalid JSON-LD syntax; lists of lists are not ' 'permitted.', 'jsonld.SyntaxError', code='list of lists') # drop None values if e is not None: if _is_array(e): rval.extend(e) else: rval.append(e) return rval # handle scalars if not _is_object(element): # drop free-floating scalars that are not in lists if (not inside_list and (active_property is None or self._expand_iri( active_ctx, active_property, vocab=True) == '@graph')): return None # expand element according to value expansion rules return self._expand_value(active_ctx, active_property, element) # recursively expand object # if element has a context, process it if '@context' in element: active_ctx = self._process_context( active_ctx, element['@context'], options) # expand the active property expanded_active_property = self._expand_iri( active_ctx, active_property, vocab=True) rval = {} for key, value in sorted(element.items()): if key == '@context': continue # expand key to IRI expanded_property = self._expand_iri( active_ctx, key, vocab=True) # drop non-absolute IRI keys that aren't keywords if (expanded_property is None or not (_is_absolute_iri(expanded_property) or _is_keyword(expanded_property))): continue if _is_keyword(expanded_property): if expanded_active_property == '@reverse': raise JsonLdError( 'Invalid JSON-LD syntax; a keyword cannot be used as ' 'a @reverse property.', 'jsonld.SyntaxError', {'value': value}, code='invalid reverse property map') if expanded_property in rval: raise JsonLdError( 'Invalid JSON-LD syntax; colliding keywords detected.', 'jsonld.SyntaxError', {'keyword': expanded_property}, code='colliding keywords') # syntax error if @id is not a string if expanded_property == '@id' and not _is_string(value): if not options.get('isFrame'): raise JsonLdError( 'Invalid JSON-LD syntax; "@id" value must a string.', 'jsonld.SyntaxError', {'value': value}, code='invalid @id value') if not _is_object(value): raise JsonLdError( 'Invalid JSON-LD syntax; "@id" value must be a ' 'string or an object.', 'jsonld.SyntaxError', {'value': value}, code='invalid @id value') if expanded_property == '@type': _validate_type_value(value) # @graph must be an array or an object if (expanded_property == '@graph' and not (_is_object(value) or _is_array(value))): raise JsonLdError( 'Invalid JSON-LD syntax; "@graph" must not be an ' 'object or an array.', 'jsonld.SyntaxError', {'value': value}, code='invalid @graph value') # @value must not be an object or an array if (expanded_property == '@value' and (_is_object(value) or _is_array(value))): raise JsonLdError( 'Invalid JSON-LD syntax; "@value" value must not be an ' 'object or an array.', 'jsonld.SyntaxError', {'value': value}, code='invalid value object value') # @language must be a string if expanded_property == '@language': if value is None: # drop null @language values, they expand as if they # didn't exist continue if not _is_string(value): raise JsonLdError( 'Invalid JSON-LD syntax; "@language" value must be ' 'a string.', 'jsonld.SyntaxError', {'value': value}, code='invalid language-tagged string') # ensure language value is lowercase value = value.lower() # @index must be a string if expanded_property == '@index' and not _is_string(value): raise JsonLdError( 'Invalid JSON-LD syntax; "@index" value must be ' 'a string.', 'jsonld.SyntaxError', {'value': value}, code='invalid @index value') # reverse must be an object if expanded_property == '@reverse': if not _is_object(value): raise JsonLdError( 'Invalid JSON-LD syntax; "@reverse" value must be ' 'an object.', 'jsonld.SyntaxError', {'value': value}, code='invalid @reverse value') expanded_value = self._expand( active_ctx, '@reverse', value, options, inside_list) # properties double-reversed if '@reverse' in expanded_value: for rprop, rvalue in expanded_value['@reverse'].items(): JsonLdProcessor.add_value( rval, rprop, rvalue, {'propertyIsArray': True}) # merge in all reversed properties reverse_map = rval.get('@reverse') for property, items in expanded_value.items(): if property == '@reverse': continue if reverse_map is None: reverse_map = rval['@reverse'] = {} JsonLdProcessor.add_value( reverse_map, property, [], {'propertyIsArray': True}) for item in items: if _is_value(item) or _is_list(item): raise JsonLdError( 'Invalid JSON-LD syntax; "@reverse" ' 'value must not be an @value or an @list', 'jsonld.SyntaxError', {'value': expanded_value}, code='invalid reverse property value') JsonLdProcessor.add_value( reverse_map, property, item, {'propertyIsArray': True}) continue container = JsonLdProcessor.get_context_value( active_ctx, key, '@container') # handle language map container (skip if value is not an object) if container == '@language' and _is_object(value): expanded_value = self._expand_language_map(value) # handle index container (skip if value is not an object) elif container == '@index' and _is_object(value): def expand_index_map(active_property): rval = [] for k, v in sorted(value.items()): v = self._expand( active_ctx, active_property, JsonLdProcessor.arrayify(v), options, inside_list=False) for item in v: item.setdefault('@index', k) rval.append(item) return rval expanded_value = expand_index_map(key) else: # recurse into @list or @set is_list = (expanded_property == '@list') if is_list or expanded_property == '@set': next_active_property = active_property if is_list and expanded_active_property == '@graph': next_active_property = None expanded_value = self._expand( active_ctx, next_active_property, value, options, is_list) if is_list and _is_list(expanded_value): raise JsonLdError( 'Invalid JSON-LD syntax; lists of lists are ' 'not permitted.', 'jsonld.SyntaxError', code='list of lists') else: # recursively expand value w/key as new active property expanded_value = self._expand( active_ctx, key, value, options, inside_list=False) # drop None values if property is not @value (dropped below) if expanded_value is None and expanded_property != '@value': continue # convert expanded value to @list if container specifies it if (expanded_property != '@list' and not _is_list(expanded_value) and container == '@list'): # ensure expanded value is an array expanded_value = { '@list': JsonLdProcessor.arrayify(expanded_value) } # merge in reverse properties mapping = active_ctx['mappings'].get(key) if mapping and mapping['reverse']: reverse_map = rval.setdefault('@reverse', {}) expanded_value = JsonLdProcessor.arrayify(expanded_value) for item in expanded_value: if _is_value(item) or _is_list(item): raise JsonLdError( 'Invalid JSON-LD syntax; "@reverse" value must ' 'not be an @value or an @list.', 'jsonld.SyntaxError', {'value': expanded_value}, code='invalid reverse property value') JsonLdProcessor.add_value( reverse_map, expanded_property, item, {'propertyIsArray': True}) continue # add value for property, use an array exception for certain # key words use_array = (expanded_property not in ['@index', '@id', '@type', '@value', '@language']) JsonLdProcessor.add_value( rval, expanded_property, expanded_value, {'propertyIsArray': use_array}) # get property count on expanded output count = len(rval) if '@value' in rval: # @value must only have @language or @type if '@type' in rval and '@language' in rval: raise JsonLdError( 'Invalid JSON-LD syntax; an element containing ' '"@value" may not contain both "@type" and "@language".', 'jsonld.SyntaxError', {'element': rval}, code='invalid value object') valid_count = count - 1 if '@type' in rval: valid_count -= 1 if '@index' in rval: valid_count -= 1 if '@language' in rval: valid_count -= 1 if valid_count != 0: raise JsonLdError( 'Invalid JSON-LD syntax; an element containing "@value" ' 'may only have an "@index" property and at most one other ' 'property which can be "@type" or "@language".', 'jsonld.SyntaxError', {'element': rval}, code='invalid value object') # drop None @values if rval['@value'] is None: rval = None # if @language is present, @value must be a string elif '@language' in rval and not _is_string(rval['@value']): raise JsonLdError( 'Invalid JSON-LD syntax; only strings may be ' 'language-tagged.', 'jsonld.SyntaxError', {'element': rval}, code='invalid language-tagged value') elif ('@type' in rval and (not _is_absolute_iri(rval['@type']) or rval['@type'].startswith('_:'))): raise JsonLdError( 'Invalid JSON-LD syntax; an element containing "@value" ' 'and "@type" must have an absolute IRI for the value ' 'of "@type".', 'jsonld.SyntaxError', {'element': rval}, code='invalid typed value') # convert @type to an array elif '@type' in rval and not _is_array(rval['@type']): rval['@type'] = [rval['@type']] # handle @set and @list elif '@set' in rval or '@list' in rval: if count > 1 and not (count == 2 and '@index' in rval): raise JsonLdError( 'Invalid JSON-LD syntax; if an element has the ' 'property "@set" or "@list", then it can have at most ' 'one other property, which is "@index".', 'jsonld.SyntaxError', {'element': rval}, code='invalid set or list object') # optimize away @set if '@set' in rval: rval = rval['@set'] count = len(rval) # drop objects with only @language elif count == 1 and '@language' in rval: rval = None # drop certain top-level objects that do not occur in lists if (_is_object(rval) and not options.get('keepFreeFloatingNodes') and not inside_list and (active_property is None or expanded_active_property == '@graph')): # drop empty object or top-level @value/@list, # or object with only @id if (count == 0 or '@value' in rval or '@list' in rval or (count == 1 and '@id' in rval)): rval = None return rval def _flatten(self, input): """ Performs JSON-LD flattening. :param input_: the expanded JSON-LD to flatten. :return: the flattened JSON-LD output. """ # produce a map of all subjects and name each bnode namer = UniqueNamer('_:b') graphs = {'@default': {}} self._create_node_map(input, graphs, '@default', namer) # add all non-default graphs to default graph default_graph = graphs['@default'] for graph_name, node_map in graphs.items(): if graph_name == '@default': continue graph_subject = default_graph.setdefault( graph_name, {'@id': graph_name, '@graph': []}) graph_subject.setdefault('@graph', []).extend( [v for k, v in sorted(node_map.items()) if not _is_subject_reference(v)]) # produce flattened output return [value for key, value in sorted(default_graph.items()) if not _is_subject_reference(value)] def _frame(self, input_, frame, options): """ Performs JSON-LD framing. :param input_: the expanded JSON-LD to frame. :param frame: the expanded JSON-LD frame to use. :param options: the framing options. :return: the framed output. """ # create framing state state = { 'options': options, 'graphs': {'@default': {}, '@merged': {}}, 'subjectStack': [], 'link': {} } # produce a map of all graphs and name each bnode # FIXME: currently uses subjects from @merged graph only namer = UniqueNamer('_:b') self._create_node_map(input_, state['graphs'], '@merged', namer) state['subjects'] = state['graphs']['@merged'] # frame the subjects framed = [] self._match_frame( state, sorted(state['subjects'].keys()), frame, framed, None) return framed def _normalize(self, dataset, options): """ Performs RDF normalization on the given RDF dataset. :param dataset: the RDF dataset to normalize. :param options: the normalization options. :return: the normalized output. """ # create quads and map bnodes to their associated quads quads = [] bnodes = {} for graph_name, triples in dataset.items(): if graph_name == '@default': graph_name = None for triple in triples: quad = triple if graph_name is not None: if graph_name.startswith('_:'): quad['name'] = {'type': 'blank node'} else: quad['name'] = {'type': 'IRI'} quad['name']['value'] = graph_name quads.append(quad) for attr in ['subject', 'object', 'name']: if attr in quad and quad[attr]['type'] == 'blank node': id_ = quad[attr]['value'] bnodes.setdefault(id_, {}).setdefault( 'quads', []).append(quad) # mapping complete, start canonical naming namer = UniqueNamer('_:c14n') # continue to hash bnode quads while bnodes are assigned names unnamed = None next_unnamed = bnodes.keys() duplicates = None while True: unnamed = next_unnamed next_unnamed = [] duplicates = {} unique = {} for bnode in unnamed: # hash quads for each unnamed bnode hash = self._hash_quads(bnode, bnodes) # store hash as unique or a duplicate if hash in duplicates: duplicates[hash].append(bnode) next_unnamed.append(bnode) elif hash in unique: duplicates[hash] = [unique[hash], bnode] next_unnamed.append(unique[hash]) next_unnamed.append(bnode) del unique[hash] else: unique[hash] = bnode # name unique bnodes in sorted hash order for hash, bnode in sorted(unique.items()): namer.get_name(bnode) # done when no more bnodes named if len(unnamed) == len(next_unnamed): break # enumerate duplicate hash groups in sorted order for hash, group in sorted(duplicates.items()): # process group results = [] for bnode in group: # skip already-named bnodes if namer.is_named(bnode): continue # hash bnode paths path_namer = UniqueNamer('_:b') path_namer.get_name(bnode) results.append(self._hash_paths( bnode, bnodes, namer, path_namer)) # name bnodes in hash order cmp_hashes = cmp_to_key(lambda x, y: cmp(x['hash'], y['hash'])) for result in sorted(results, key=cmp_hashes): # name all bnodes in path namer in key-entry order for bnode in result['pathNamer'].order: namer.get_name(bnode) # create normalized array normalized = [] # Note: At this point all bnodes in the set of RDF quads have been # assigned canonical names, which have been stored in the 'namer' # object. Here each quad is updated by assigning each of its bnodes its # new name via the 'namer' object. # update bnode names in each quad and serialize for quad in quads: for attr in ['subject', 'object', 'name']: if (attr in quad and quad[attr]['type'] == 'blank node' and not quad[attr]['value'].startswith('_:c14n')): quad[attr]['value'] = namer.get_name(quad[attr]['value']) normalized.append(JsonLdProcessor.to_nquad( quad, quad['name']['value'] if 'name' in quad else None)) # sort normalized output normalized.sort() # handle output format if 'format' in options: if options['format'] == 'application/nquads': return ''.join(normalized) raise JsonLdError( 'Unknown output format.', 'jsonld.UnknownFormat', {'format': options['format']}) # return parsed RDF dataset return JsonLdProcessor.parse_nquads(''.join(normalized)) def _from_rdf(self, dataset, options): """ Converts an RDF dataset to JSON-LD. :param dataset: the RDF dataset. :param options: the RDF serialization options. :return: the JSON-LD output. """ default_graph = {} graph_map = {'@default': default_graph} referenced_once = {} for name, graph in dataset.items(): graph_map.setdefault(name, {}) if name != '@default' and name not in default_graph: default_graph[name] = {'@id': name} node_map = graph_map[name] for triple in graph: # get subject, predicate, object s = triple['subject']['value'] p = triple['predicate']['value'] o = triple['object'] node = node_map.setdefault(s, {'@id': s}) object_is_id = (o['type'] == 'IRI' or o['type'] == 'blank node') if object_is_id and o['value'] not in node_map: node_map[o['value']] = {'@id': o['value']} if (p == RDF_TYPE and not options.get('useRdfType', False) and object_is_id): JsonLdProcessor.add_value( node, '@type', o['value'], {'propertyIsArray': True}) continue value = self._rdf_to_object(o, options['useNativeTypes']) JsonLdProcessor.add_value( node, p, value, {'propertyIsArray': True}) # object may be an RDF list/partial list node but we # can't know easily until all triples are read if object_is_id: # track rdf:nil uniquely per graph if o['value'] == RDF_NIL: object = node_map[o['value']] if 'usages' not in object: object['usages'] = [] object['usages'].append({ 'node': node, 'property': p, 'value': value }) # object referenced more than once elif o['value'] in referenced_once: referenced_once[o['value']] = False # track single reference else: referenced_once[o['value']] = { 'node': node, 'property': p, 'value': value } # convert linked lists to @list arrays for name, graph_object in graph_map.items(): # no @lists to be converted, continue if RDF_NIL not in graph_object: continue # iterate backwards through each RDF list nil = graph_object[RDF_NIL] for usage in nil['usages']: node = usage['node'] property = usage['property'] head = usage['value'] list_ = [] list_nodes = [] # ensure node is a well-formed list node; it must: # 1. Be referenced only once. # 2. Have an array for rdf:first that has 1 item. # 3. Have an array for rdf:rest that has 1 item # 4. Have no keys other than: @id, rdf:first, rdf:rest # and, optionally, @type where the value is rdf:List. node_key_count = len(node.keys()) while(property == RDF_REST and _is_object(referenced_once.get(node['@id'])) and _is_array(node[RDF_FIRST]) and len(node[RDF_FIRST]) == 1 and _is_array(node[RDF_REST]) and len(node[RDF_REST]) == 1 and (node_key_count == 3 or (node_key_count == 4 and _is_array(node.get('@type')) and len(node['@type']) == 1 and node['@type'][0] == RDF_LIST))): list_.append(node[RDF_FIRST][0]) list_nodes.append(node['@id']) # get next node, moving backwards through list usage = referenced_once[node['@id']] node = usage['node'] property = usage['property'] head = usage['value'] node_key_count = len(node.keys()) # if node is not a blank node, then list head found if not node['@id'].startswith('_:'): break # the list is nested in another list if property == RDF_FIRST: # empty list if node['@id'] == RDF_NIL: # can't convert rdf:nil to a @list object because it # would result in a list of lists which isn't supported continue # preserve list head head = graph_object[head['@id']][RDF_REST][0] list_.pop() list_nodes.pop() # transform list into @list object del head['@id'] list_.reverse() head['@list'] = list_ for node in list_nodes: graph_object.pop(node, None) nil.pop('usages', None) result = [] for subject, node in sorted(default_graph.items()): if subject in graph_map: graph = node['@graph'] = [] for s, n in sorted(graph_map[subject].items()): # only add full subjects to top-level if not _is_subject_reference(n): graph.append(n) # only add full subjects to top-level if not _is_subject_reference(node): result.append(node) return result def _process_context(self, active_ctx, local_ctx, options): """ Processes a local context and returns a new active context. :param active_ctx: the current active context. :param local_ctx: the local context to process. :param options: the context processing options. :return: the new active context. """ global _cache # normalize local context to an array if _is_object(local_ctx) and _is_array(local_ctx.get('@context')): local_ctx = local_ctx['@context'] ctxs = JsonLdProcessor.arrayify(local_ctx) # no contexts in array, clone existing context if len(ctxs) == 0: return self._clone_active_context(active_ctx) # process each context in order, update active context on each # iteration to ensure proper caching rval = active_ctx for ctx in ctxs: # reset to initial context if ctx is None: rval = active_ctx = self._get_initial_context(options) continue # dereference @context key if present if _is_object(ctx) and '@context' in ctx: ctx = ctx['@context'] # context must be an object now, all URLs retrieved prior to call if not _is_object(ctx): raise JsonLdError( 'Invalid JSON-LD syntax; @context must be an object.', 'jsonld.SyntaxError', {'context': ctx}, code='invalid local context') # get context from cache if available if _cache.get('activeCtx') is not None: cached = _cache['activeCtx'].get(active_ctx, ctx) if cached: rval = active_ctx = cached continue # update active context and clone new one before updating active_ctx = rval rval = self._clone_active_context(active_ctx) # define context mappings for keys in local context defined = {} # handle @base if '@base' in ctx: base = ctx['@base'] if base is None: base = None elif not _is_string(base): raise JsonLdError( 'Invalid JSON-LD syntax; the value of "@base" in a ' '@context must be a string or null.', 'jsonld.SyntaxError', {'context': ctx}, code='invalid base IRI') elif base != '' and not _is_absolute_iri(base): raise JsonLdError( 'Invalid JSON-LD syntax; the value of "@base" in a ' '@context must be an absolute IRI or the empty ' 'string.', 'jsonld.SyntaxError', {'context': ctx}, code='invalid base IRI') rval['@base'] = base defined['@base'] = True # handle @vocab if '@vocab' in ctx: value = ctx['@vocab'] if value is None: del rval['@vocab'] elif not _is_string(value): raise JsonLdError( 'Invalid JSON-LD syntax; the value of "@vocab" in a ' '@context must be a string or null.', 'jsonld.SyntaxError', {'context': ctx}, code='invalid vocab mapping') elif not _is_absolute_iri(value): raise JsonLdError( 'Invalid JSON-LD syntax; the value of "@vocab" in a ' '@context must be an absolute IRI.', 'jsonld.SyntaxError', {'context': ctx}, code='invalid vocab mapping') else: rval['@vocab'] = value defined['@vocab'] = True # handle @language if '@language' in ctx: value = ctx['@language'] if value is None: del rval['@language'] elif not _is_string(value): raise JsonLdError( 'Invalid JSON-LD syntax; the value of "@language" in ' 'a @context must be a string or null.', 'jsonld.SyntaxError', {'context': ctx}, code='invalid default language') else: rval['@language'] = value.lower() defined['@language'] = True # process all other keys for k, v in ctx.items(): self._create_term_definition(rval, ctx, k, defined) # cache result if _cache.get('activeCtx') is not None: _cache.get('activeCtx').set(active_ctx, ctx, rval) return rval def _expand_language_map(self, language_map): """ Expands a language map. :param language_map: the language map to expand. :return: the expanded language map. """ rval = [] for key, values in sorted(language_map.items()): values = JsonLdProcessor.arrayify(values) for item in values: if not _is_string(item): raise JsonLdError( 'Invalid JSON-LD syntax; language map values must be ' 'strings.', 'jsonld.SyntaxError', {'languageMap': language_map}, code='invalid language map value') rval.append({'@value': item, '@language': key.lower()}) return rval def _expand_value(self, active_ctx, active_property, value): """ Expands the given value by using the coercion and keyword rules in the given context. :param active_ctx: the active context to use. :param active_property: the property the value is associated with. :param value: the value to expand. :return: the expanded value. """ # nothing to expand if value is None: return None # special-case expand @id and @type (skips '@id' expansion) expanded_property = self._expand_iri( active_ctx, active_property, vocab=True) if expanded_property == '@id': return self._expand_iri(active_ctx, value, base=True) elif expanded_property == '@type': return self._expand_iri(active_ctx, value, vocab=True, base=True) # get type definition from context type_ = JsonLdProcessor.get_context_value( active_ctx, active_property, '@type') # do @id expansion (automatic for @graph) if (type_ == '@id' or (expanded_property == '@graph' and _is_string(value))): return {'@id': self._expand_iri(active_ctx, value, base=True)} # do @id expansion w/vocab if type_ == '@vocab': return {'@id': self._expand_iri( active_ctx, value, vocab=True, base=True)} # do not expand keyword values if _is_keyword(expanded_property): return value rval = {} # other type if type_ is not None: rval['@type'] = type_ # check for language tagging elif _is_string(value): language = JsonLdProcessor.get_context_value( active_ctx, active_property, '@language') if language is not None: rval['@language'] = language rval['@value'] = value return rval def _graph_to_rdf(self, graph, namer, options): """ Creates an array of RDF triples for the given graph. :param graph: the graph to create RDF triples for. :param namer: the UniqueNamer for assigning blank node names. :param options: the RDF serialization options. :return: the array of RDF triples for the given graph. """ rval = [] for id_, node in sorted(graph.items()): for property, items in sorted(node.items()): if property == '@type': property = RDF_TYPE elif _is_keyword(property): continue for item in items: # skip relative IRI subjects and predicates if not (_is_absolute_iri(id_) and _is_absolute_iri(property)): continue # RDF subject subject = {} if id_.startswith('_:'): subject['type'] = 'blank node' else: subject['type'] = 'IRI' subject['value'] = id_ # RDF predicate predicate = {} if property.startswith('_:'): # skip bnode predicates unless producing # generalized RDF if not options['produceGeneralizedRdf']: continue predicate['type'] = 'blank node' else: predicate['type'] = 'IRI' predicate['value'] = property # convert @list to triples if _is_list(item): self._list_to_rdf( item['@list'], namer, subject, predicate, rval) # convert value or node object to triple else: object = self._object_to_rdf(item) # skip None objects (they are relative IRIs) if object is not None: rval.append({ 'subject': subject, 'predicate': predicate, 'object': object }) return rval def _list_to_rdf(self, list, namer, subject, predicate, triples): """ Converts a @list value into a linked list of blank node RDF triples (and RDF collection). :param list: the @list value. :param namer: the UniqueNamer for assigning blank node names. :param subject: the subject for the head of the list. :param predicate: the predicate for the head of the list. :param triples: the array of triples to append to. """ first = {'type': 'IRI', 'value': RDF_FIRST} rest = {'type': 'IRI', 'value': RDF_REST} nil = {'type': 'IRI', 'value': RDF_NIL} for item in list: blank_node = {'type': 'blank node', 'value': namer.get_name()} triples.append({ 'subject': subject, 'predicate': predicate, 'object': blank_node }) subject = blank_node predicate = first object = self._object_to_rdf(item) # skip None objects (they are relative IRIs) if object is not None: triples.append({ 'subject': subject, 'predicate': predicate, 'object': object }) predicate = rest triples.append({ 'subject': subject, 'predicate': predicate, 'object': nil }) def _object_to_rdf(self, item): """ Converts a JSON-LD value object to an RDF literal or a JSON-LD string or node object to an RDF resource. :param item: the JSON-LD value or node object. :return: the RDF literal or RDF resource. """ object = {} if _is_value(item): object['type'] = 'literal' value = item['@value'] datatype = item.get('@type') # convert to XSD datatypes as appropriate if _is_bool(value): object['value'] = 'true' if value else 'false' object['datatype'] = datatype or XSD_BOOLEAN elif _is_double(value) or datatype == XSD_DOUBLE: # canonical double representation object['value'] = re.sub(r'(\d)0*E\+?0*(\d)', r'\1E\2', ('%1.15E' % value)) object['datatype'] = datatype or XSD_DOUBLE elif _is_integer(value): object['value'] = str(value) object['datatype'] = datatype or XSD_INTEGER elif '@language' in item: object['value'] = value object['datatype'] = datatype or RDF_LANGSTRING object['language'] = item['@language'] else: object['value'] = value object['datatype'] = datatype or XSD_STRING # convert string/node object to RDF else: id_ = item['@id'] if _is_object(item) else item if id_.startswith('_:'): object['type'] = 'blank node' else: object['type'] = 'IRI' object['value'] = id_ # skip relative IRIs if object['type'] == 'IRI' and not _is_absolute_iri(object['value']): return None return object def _rdf_to_object(self, o, use_native_types): """ Converts an RDF triple object to a JSON-LD object. :param o: the RDF triple object to convert. :param use_native_types: True to output native types, False not to. :return: the JSON-LD object. """ # convert IRI/BlankNode object to JSON-LD if o['type'] == 'IRI' or o['type'] == 'blank node': return {'@id': o['value']} # convert literal object to JSON-LD rval = {'@value': o['value']} # add language if 'language' in o: rval['@language'] = o['language'] # add datatype else: type_ = o['datatype'] # use native types for certain xsd types if use_native_types: if type_ == XSD_BOOLEAN: if rval['@value'] == 'true': rval['@value'] = True elif rval['@value'] == 'false': rval['@value'] = False elif _is_numeric(rval['@value']): if type_ == XSD_INTEGER: if rval['@value'].isdigit(): rval['@value'] = int(rval['@value']) elif type_ == XSD_DOUBLE: rval['@value'] = float(rval['@value']) # do not add native type if type_ not in [XSD_BOOLEAN, XSD_INTEGER, XSD_DOUBLE, XSD_STRING]: rval['@type'] = type_ elif type_ != XSD_STRING: rval['@type'] = type_ return rval def _create_node_map( self, input_, graphs, graph, namer, name=None, list_=None): """ Recursively flattens the subjects in the given JSON-LD expanded input into a node map. :param input_: the JSON-LD expanded input. :param graphs: a map of graph name to subject map. :param graph: the name of the current graph. :param namer: the UniqueNamer for assigning blank node names. :param name: the name assigned to the current input if it is a bnode. :param list_: the list to append to, None for none. """ # recurse through array if _is_array(input_): for e in input_: self._create_node_map(e, graphs, graph, namer, None, list_) return # add non-object to list if not _is_object(input_): if list_ is not None: list_.append(input_) return # add values to list if _is_value(input_): if '@type' in input_: type_ = input_['@type'] # rename @type blank node if type_.startswith('_:'): type_ = input_['@type'] = namer.get_name(type_) if list_ is not None: list_.append(input_) return # Note: At this point, input must be a subject. # spec requires @type to be named first, so assign names early if '@type' in input_: for type_ in input_['@type']: if type_.startswith('_:'): namer.get_name(type_) # get name for subject if name is None: name = input_.get('@id') if _is_bnode(input_): name = namer.get_name(name) # add subject reference to list if list_ is not None: list_.append({'@id': name}) # create new subject or merge into existing one subject = graphs.setdefault(graph, {}).setdefault(name, {'@id': name}) for property, objects in sorted(input_.items()): # skip @id if property == '@id': continue # handle reverse properties if property == '@reverse': referenced_node = {'@id': name} reverse_map = input_['@reverse'] for reverse_property, items in reverse_map.items(): for item in items: item_name = item.get('@id') if _is_bnode(item): item_name = namer.get_name(item_name) self._create_node_map( item, graphs, graph, namer, item_name) JsonLdProcessor.add_value( graphs[graph][item_name], reverse_property, referenced_node, {'propertyIsArray': True, 'allowDuplicate': False}) continue # recurse into graph if property == '@graph': # add graph subjects map entry graphs.setdefault(name, {}) g = graph if graph == '@merged' else name self._create_node_map(objects, graphs, g, namer) continue # copy non-@type keywords if property != '@type' and _is_keyword(property): if property == '@index' and '@index' in subject \ and (input_['@index'] != subject['@index'] or input_['@index']['@id'] != subject['@index']['@id']): raise JsonLdError( 'Invalid JSON-LD syntax; conflicting @index property ' ' detected.', 'jsonld.SyntaxError', {'subject': subject}, code='conflicting indexes') subject[property] = input_[property] continue # if property is a bnode, assign it a new id if property.startswith('_:'): property = namer.get_name(property) # ensure property is added for empty arrays if len(objects) == 0: JsonLdProcessor.add_value( subject, property, [], {'propertyIsArray': True}) continue for o in objects: if property == '@type': # rename @type blank nodes o = namer.get_name(o) if o.startswith('_:') else o # handle embedded subject or subject reference if _is_subject(o) or _is_subject_reference(o): # rename blank node @id id_ = o.get('@id') if _is_bnode(o): id_ = namer.get_name(id_) # add reference and recurse JsonLdProcessor.add_value( subject, property, {'@id': id_}, {'propertyIsArray': True, 'allowDuplicate': False}) self._create_node_map(o, graphs, graph, namer, id_) # handle @list elif _is_list(o): olist = [] self._create_node_map( o['@list'], graphs, graph, namer, name, olist) o = {'@list': olist} JsonLdProcessor.add_value( subject, property, o, {'propertyIsArray': True, 'allowDuplicate': False}) # handle @value else: self._create_node_map(o, graphs, graph, namer, name) JsonLdProcessor.add_value( subject, property, o, {'propertyIsArray': True, 'allowDuplicate': False}) def _match_frame(self, state, subjects, frame, parent, property): """ Frames subjects according to the given frame. :param state: the current framing state. :param subjects: the subjects to filter. :param frame: the frame. :param parent: the parent subject or top-level array. :param property: the parent property, initialized to None. """ # validate the frame self._validate_frame(frame) frame = frame[0] # get flags for current frame options = state['options'] flags = { 'embed': self._get_frame_flag(frame, options, 'embed'), 'explicit': self._get_frame_flag(frame, options, 'explicit'), 'requireAll': self._get_frame_flag(frame, options, 'requireAll') } # filter out subjects that match the frame matches = self._filter_subjects(state, subjects, frame, flags) # add matches to output for id_, subject in sorted(matches.items()): if flags['embed'] == '@link' and id_ in state['link']: # TODO: may want to also match an existing linked subject # against the current frame ... so different frames could # produce different subjects that are only shared in-memory # when the frames are the same # add existing linked subject self._add_frame_output(parent, property, state['link'][id_]) continue # Note: In order to treat each top-level match as a # compartmentalized result, clear the unique embedded subjects map # when the property is None, which only occurs at the top-level. if property is None: state['uniqueEmbeds'] = {} # start output for subject output = {'@id': id_} state['link'][id_] = output # if embed is @never or if a circular reference would be created # by an embed, the subject cannot be embedded, just add the # reference; note that a circular reference won't occur when the # embed flag is `@link` as the above check will short-circuit # before reaching this point if(flags['embed'] == '@never' or self._creates_circular_reference( subject, state['subjectStack'])): self._add_frame_output(parent, property, output) continue # if only the last match should be embedded if flags['embed'] == '@last': # remove any existing embed if id_ in state['uniqueEmbeds']: self._remove_embed(state, id_) state['uniqueEmbeds'][id_] = { 'parent': parent, 'property': property } # push matching subject onto stack to enable circular embed checks state['subjectStack'].append(subject) # iterate over subject properties in order for prop, objects in sorted(subject.items()): # copy keywords to output if _is_keyword(prop): output[prop] = copy.deepcopy(subject[prop]) continue # explicit is on and property isn't in frame, skip processing if flags['explicit'] and prop not in frame: continue # add objects objects = subject[prop] for o in objects: # recurse into list if _is_list(o): # add empty list list_ = {'@list': []} self._add_frame_output(output, prop, list_) # add list objects src = o['@list'] for o in src: if _is_subject_reference(o): # recurse into subject reference if prop in frame: subframe = frame[prop][0]['@list'] else: subframe = self._create_implicit_frame( flags) self._match_frame( state, [o['@id']], subframe, list_, '@list') else: # include other values automatically self._add_frame_output( list_, '@list', copy.deepcopy(o)) continue if _is_subject_reference(o): # recurse into subject reference if prop in frame: subframe = frame[prop] else: subframe = self._create_implicit_frame(flags) self._match_frame( state, [o['@id']], subframe, output, prop) else: # include other values automatically self._add_frame_output(output, prop, copy.deepcopy(o)) # handle defaults in order for prop in sorted(frame.keys()): # skip keywords if _is_keyword(prop): continue # if omit default is off, then include default values for # properties that appear in the next frame but are not in # the matching subject next = frame[prop][0] omit_default_on = self._get_frame_flag( next, options, 'omitDefault') if not omit_default_on and prop not in output: preserve = '@null' if '@default' in next: preserve = copy.deepcopy(next['@default']) preserve = JsonLdProcessor.arrayify(preserve) output[prop] = [{'@preserve': preserve}] # add output to parent self._add_frame_output(parent, property, output) # pop matching subject from circular ref-checking stack state['subjectStack'].pop() def _create_implicit_frame(self, flags): """ Creates an implicit frame when recursing through subject matches. If a frame doesn't have an explicit frame for a particular property, then a wildcard child frame will be created that uses the same flags that the parent frame used. :param flags: the current framing flags. :return: the implicit frame. """ frame = {} for key in flags: frame['@' + key] = [flags[key]] return [frame] def _creates_circular_reference(self, subject_to_embed, subject_stack): """ Checks the current subject stack to see if embedding the given subject would cause a circular reference. :param subject_to_embed: the subject to embed. :param subject_stack: the current stack of subjects. :return: true if a circular reference would be created, false if not. """ for subject in reversed(subject_stack[:-1]): if subject['@id'] == subject_to_embed['@id']: return True return False def _get_frame_flag(self, frame, options, name): """ Gets the frame flag value for the given flag name. :param frame: the frame. :param options: the framing options. :param name: the flag name. :return: the flag value. """ rval = frame.get('@' + name, [options[name]])[0] if name == 'embed': # default is "@last" # backwards-compatibility support for "embed" maps: # true => "@last" # false => "@never" if rval is True: rval = '@last' elif rval is False: rval = '@never' elif rval != '@always' and rval != '@never' and rval != '@link': rval = '@last' return rval def _validate_frame(self, frame): """ Validates a JSON-LD frame, throwing an exception if the frame is invalid. :param frame: the frame to validate. """ if (not _is_array(frame) or len(frame) != 1 or not _is_object(frame[0])): raise JsonLdError( 'Invalid JSON-LD syntax; a JSON-LD frame must be a single ' 'object.', 'jsonld.SyntaxError', {'frame': frame}) def _filter_subjects(self, state, subjects, frame, flags): """ Returns a map of all of the subjects that match a parsed frame. :param state: the current framing state. :param subjects: the set of subjects to filter. :param frame: the parsed frame. :param flags: the frame flags. :return: all of the matched subjects. """ rval = {} for id_ in subjects: subject = state['subjects'][id_] if self._filter_subject(subject, frame, flags): rval[id_] = subject return rval def _filter_subject(self, subject, frame, flags): """ Returns True if the given subject matches the given frame. :param subject: the subject to check. :param frame: the frame to check. :param flags: the frame flags. :return: True if the subject matches, False if not. """ # check @type (object value means 'any' type, fall through to # ducktyping) if ('@type' in frame and not (len(frame['@type']) == 1 and _is_object(frame['@type'][0]))): types = frame['@type'] for t in types: # any matching @type is a match if JsonLdProcessor.has_value(subject, '@type', t): return True return False # check ducktype wildcard = True matches_some = False for k, v in frame.items(): if _is_keyword(k): # skip non-@id and non-@type if k != '@id' and k != '@type': continue wildcard = True # check @id for a specific @id value if k == '@id' and _is_string(v): if subject.get(k) != v: return False matches_some = True continue wildcard = False if k in subject: # v == [] means do not match if property is present if _is_array(v) and len(v) == 0: return False matches_some = True continue # all properties must match to be a duck unless a @default is # specified has_default = (_is_array(v) and len(v) == 1 and _is_object(v[0]) and '@default' in v[0]) if flags['requireAll'] and not has_default: return False # return true if wildcard or subject matches some properties return wildcard or matches_some def _remove_embed(self, state, id_): """ Removes an existing embed. :param state: the current framing state. :param id_: the @id of the embed to remove. """ # get existing embed embeds = state['uniqueEmbeds'] embed = embeds[id_] property = embed['property'] # create reference to replace embed subject = {'@id': id_} # remove existing embed if _is_array(embed['parent']): # replace subject with reference for i, parent in enumerate(embed['parent']): if JsonLdProcessor.compare_values(parent, subject): embed['parent'][i] = subject break else: # replace subject with reference use_array = _is_array(embed['parent'][property]) JsonLdProcessor.remove_value( embed['parent'], property, subject, {'propertyIsArray': use_array}) JsonLdProcessor.add_value( embed['parent'], property, subject, {'propertyIsArray': use_array}) # recursively remove dependent dangling embeds def remove_dependents(id_): # get embed keys as a separate array to enable deleting keys # in map try: ids = list(embeds.iterkeys()) except AttributeError: ids = list(embeds.keys()) for next in ids: if (next in embeds and _is_object(embeds[next]['parent']) and embeds[next]['parent']['@id'] == id_): del embeds[next] remove_dependents(next) remove_dependents(id_) def _add_frame_output(self, parent, property, output): """ Adds framing output to the given parent. :param parent: the parent to add to. :param property: the parent property. :param output: the output to add. """ if _is_object(parent): JsonLdProcessor.add_value( parent, property, output, {'propertyIsArray': True}) else: parent.append(output) def _remove_preserve(self, ctx, input_, options): """ Removes the @preserve keywords as the last step of the framing algorithm. :param ctx: the active context used to compact the input. :param input_: the framed, compacted output. :param options: the compaction options used. :return: the resulting output. """ # recurse through arrays if _is_array(input_): output = [] for e in input_: result = self._remove_preserve(ctx, e, options) # drop Nones from arrays if result is not None: output.append(result) return output elif _is_object(input_): # remove @preserve if '@preserve' in input_: if input_['@preserve'] == '@null': return None return input_['@preserve'] # skip @values if _is_value(input_): return input_ # recurse through @lists if _is_list(input_): input_['@list'] = self._remove_preserve( ctx, input_['@list'], options) return input_ # handle in-memory linked nodes id_alias = self._compact_iri(ctx, '@id') if id_alias in input_: id_ = input_[id_alias] if id_ in options['link']: try: idx = options['link'][id_].index(input_) # already visited return options['link'][id_][idx] except BaseException: # prevent circular visitation options['link'][id_].append(input_) else: # prevent circular visitation options['link'][id_] = [input_] # recurse through properties for prop, v in input_.items(): result = self._remove_preserve(ctx, v, options) container = JsonLdProcessor.get_context_value( ctx, prop, '@container') if (options['compactArrays'] and _is_array(result) and len(result) == 1 and container != '@set' and container != '@list'): result = result[0] input_[prop] = result return input_ def _hash_quads(self, id_, bnodes): """ Hashes all of the quads about a blank node. :param id_: the ID of the bnode to hash quads for. :param bnodes: the mapping of bnodes to quads. :param namer: the canonical bnode namer. :return: the new hash. """ # return cached hash if 'hash' in bnodes[id_]: return bnodes[id_]['hash'] # serialize all of bnode's quads quads = bnodes[id_]['quads'] nquads = [] for quad in quads: nquads.append(JsonLdProcessor.to_nquad( quad, quad['name']['value'] if 'name' in quad else None, id_)) # sort serialized quads nquads.sort() # cache and return hashed quads md = hashlib.sha1() md.update(''.join(nquads).encode('utf-8')) hash = bnodes[id_]['hash'] = md.hexdigest() return hash def _hash_paths(self, id_, bnodes, namer, path_namer): """ Produces a hash for the paths of adjacent bnodes for a bnode, incorporating all information about its subgraph of bnodes. This method will recursively pick adjacent bnode permutations that produce the lexicographically-least 'path' serializations. :param id_: the ID of the bnode to hash paths for. :param bnodes: the map of bnode quads. :param namer: the canonical bnode namer. :param path_namer: the namer used to assign names to adjacent bnodes. :return: the hash and path namer used. """ # create SHA-1 digest md = hashlib.sha1() # group adjacent bnodes by hash, keep properties & references separate groups = {} quads = bnodes[id_]['quads'] for quad in quads: # get adjacent bnode bnode = self._get_adjacent_bnode_name(quad['subject'], id_) if bnode is not None: # normal property direction = 'p' else: bnode = self._get_adjacent_bnode_name(quad['object'], id_) if bnode is None: continue # reference property direction = 'r' # get bnode name (try canonical, path, then hash) if namer.is_named(bnode): name = namer.get_name(bnode) elif path_namer.is_named(bnode): name = path_namer.get_name(bnode) else: name = self._hash_quads(bnode, bnodes) # hash direction, property, and bnode name/hash group_md = hashlib.sha1() group_md.update(direction.encode('utf-8')) group_md.update(quad['predicate']['value'].encode('utf-8')) group_md.update(name.encode('utf-8')) group_hash = group_md.hexdigest() # add bnode to hash group groups.setdefault(group_hash, []).append(bnode) # iterate over groups in sorted hash order for group_hash, group in sorted(groups.items()): # digest group hash md.update(group_hash.encode('utf8')) # choose a path and namer from the permutations chosen_path = None chosen_namer = None for permutation in permutations(group): path_namer_copy = copy.deepcopy(path_namer) # build adjacent path path = '' skipped = False recurse = [] for bnode in permutation: # use canonical name if available if namer.is_named(bnode): path += namer.get_name(bnode) else: # recurse if bnode isn't named in the path yet if not path_namer_copy.is_named(bnode): recurse.append(bnode) path += path_namer_copy.get_name(bnode) # skip permutation if path is already >= chosen path if (chosen_path is not None and len(path) >= len(chosen_path) and path > chosen_path): skipped = True break # recurse if not skipped: for bnode in recurse: result = self._hash_paths( bnode, bnodes, namer, path_namer_copy) path += path_namer_copy.get_name(bnode) path += '<%s>' % result['hash'] path_namer_copy = result['pathNamer'] # skip permutation if path is already >= chosen path if (chosen_path is not None and len(path) >= len(chosen_path) and path > chosen_path): skipped = True break if (not skipped and (chosen_path is None or path < chosen_path)): chosen_path = path chosen_namer = path_namer_copy # digest chosen path and update namer md.update(chosen_path.encode('utf-8')) path_namer = chosen_namer # return SHA-1 hash and path namer return {'hash': md.hexdigest(), 'pathNamer': path_namer} def _get_adjacent_bnode_name(self, node, id_): """ A helper function that gets the blank node name from an RDF quad node (subject or object). If the node is not a blank node or its value does not match the given blank node ID, it will be returned. :param node: the RDF quad node. :param id_: the ID of the blank node to look next to. :return: the adjacent blank node name or None if none was found. """ if node['type'] == 'blank node' and node['value'] != id_: return node['value'] return None def _select_term( self, active_ctx, iri, value, containers, type_or_language, type_or_language_value): """ Picks the preferred compaction term from the inverse context entry. :param active_ctx: the active context. :param iri: the IRI to pick the term for. :param value: the value to pick the term for. :param containers: the preferred containers. :param type_or_language: either '@type' or '@language'. :param type_or_language_value: the preferred value for '@type' or '@language' :return: the preferred term. """ if type_or_language_value is None: type_or_language_value = '@null' # preferred options for the value of @type or language prefs = [] # determine prefs for @id based on whether value compacts to term if ((type_or_language_value == '@id' or type_or_language_value == '@reverse') and _is_subject_reference(value)): # prefer @reverse first if type_or_language_value == '@reverse': prefs.append('@reverse') # try to compact value to a term term = self._compact_iri( active_ctx, value['@id'], None, vocab=True) mapping = active_ctx['mappings'].get(term) if term is not None and mapping and mapping['@id'] == value['@id']: # prefer @vocab prefs.extend(['@vocab', '@id']) else: # prefer @id prefs.extend(['@id', '@vocab']) else: prefs.append(type_or_language_value) prefs.append('@none') container_map = active_ctx['inverse'][iri] for container in containers: # skip container if not in map if container not in container_map: continue type_or_language_value_map = ( container_map[container][type_or_language]) for pref in prefs: # skip type/language preference if not in map if pref not in type_or_language_value_map: continue return type_or_language_value_map[pref] return None def _compact_iri( self, active_ctx, iri, value=None, vocab=False, reverse=False): """ Compacts an IRI or keyword into a term or CURIE if it can be. If the IRI has an associated value it may be passed. :param active_ctx: the active context to use. :param iri: the IRI to compact. :param value: the value to check or None. :param vocab: True to compact using @vocab if available, False not to. :param reverse: True if a reverse property is being compacted, False if not. :return: the compacted term, prefix, keyword alias, or original IRI. """ # can't compact None if iri is None: return iri # term is a keyword, force vocab to True if _is_keyword(iri): vocab = True # use inverse context to pick a term if iri is relative to vocab if vocab and iri in self._get_inverse_context(active_ctx): default_language = active_ctx.get('@language', '@none') # prefer @index if available in value containers = [] if _is_object(value) and '@index' in value: containers.append('@index') # defaults for term selection based on type/language type_or_language = '@language' type_or_language_value = '@null' if reverse: type_or_language = '@type' type_or_language_value = '@reverse' containers.append('@set') # choose most specific term that works for all elements in @list elif _is_list(value): # only select @list containers if @index is NOT in value if '@index' not in value: containers.append('@list') list_ = value['@list'] common_language = default_language if len(list_) == 0 else None common_type = None for item in list_: item_language = '@none' item_type = '@none' if _is_value(item): if '@language' in item: item_language = item['@language'] elif '@type' in item: item_type = item['@type'] # plain literal else: item_language = '@null' else: item_type = '@id' if common_language is None: common_language = item_language elif item_language != common_language and _is_value(item): common_language = '@none' if common_type is None: common_type = item_type elif item_type != common_type: common_type = '@none' # there are different languages and types in the list, so # choose the most generic term, no need to keep iterating if common_language == '@none' and common_type == '@none': break if common_language is None: common_language = '@none' if common_type is None: common_type = '@none' if common_type != '@none': type_or_language = '@type' type_or_language_value = common_type else: type_or_language_value = common_language # non-@list else: if _is_value(value): if '@language' in value and '@index' not in value: containers.append('@language') type_or_language_value = value['@language'] elif '@type' in value: type_or_language = '@type' type_or_language_value = value['@type'] else: type_or_language = '@type' type_or_language_value = '@id' containers.append('@set') # do term selection containers.append('@none') term = self._select_term( active_ctx, iri, value, containers, type_or_language, type_or_language_value) if term is not None: return term # no term match, use @vocab if available if vocab: if '@vocab' in active_ctx: vocab_ = active_ctx['@vocab'] if iri.startswith(vocab_) and iri != vocab_: # use suffix as relative iri if it is not a term in the # active context suffix = iri[len(vocab_):] if suffix not in active_ctx['mappings']: return suffix # no term or @vocab match, check for possible CURIEs candidate = None for term, definition in active_ctx['mappings'].items(): # skip terms with colons, they can't be prefixes if ':' in term: continue # skip entries with @ids that are not partial matches if (definition is None or definition['@id'] == iri or not iri.startswith(definition['@id'])): continue # a CURIE is usable if: # 1. it has no mapping, OR # 2. value is None, which means we're not compacting an @value, AND # the mapping matches the IRI curie = term + ':' + iri[len(definition['@id']):] is_usable_curie = ( curie not in active_ctx['mappings'] or (value is None and active_ctx['mappings'].get(curie, {}).get('@id') == iri)) # select curie if it is shorter or the same length but # lexicographically less than the current choice if (is_usable_curie and (candidate is None or _compare_shortest_least(curie, candidate) < 0)): candidate = curie # return curie candidate if candidate is not None: return candidate # compact IRI relative to base if not vocab: return remove_base(active_ctx['@base'], iri) # return IRI as is return iri def _compact_value(self, active_ctx, active_property, value): """ Performs value compaction on an object with @value or @id as the only property. :param active_ctx: the active context. :param active_property: the active property that points to the value. :param value: the value to compact. """ if _is_value(value): # get context rules type_ = JsonLdProcessor.get_context_value( active_ctx, active_property, '@type') language = JsonLdProcessor.get_context_value( active_ctx, active_property, '@language') container = JsonLdProcessor.get_context_value( active_ctx, active_property, '@container') # whether or not the value has an @index that must be preserved preserve_index = '@index' in value and container != '@index' # if there's no @index to preserve if not preserve_index: # matching @type or @language specified in context, compact if (('@type' in value and value['@type'] == type_) or ('@language' in value and value['@language'] == language)): return value['@value'] # return just the value of @value if all are true: # 1. @value is the only key or @index isn't being preserved # 2. there is no default language or @value is not a string or # the key has a mapping with a null @language key_count = len(value) is_value_only_key = \ (key_count == 1 or (key_count == 2 and '@index' in value and not preserve_index)) has_default_language = '@language' in active_ctx is_value_string = _is_string(value['@value']) has_null_mapping = ( active_ctx['mappings'].get(active_property) is not None and '@language' in active_ctx['mappings'][active_property] and active_ctx['mappings'][active_property]['@language'] is None) if (is_value_only_key and ( not has_default_language or not is_value_string or has_null_mapping)): return value['@value'] rval = {} # preserve @index if preserve_index: rval[self._compact_iri(active_ctx, '@index')] = value['@index'] # compact @type IRI if '@type' in value: rval[self._compact_iri(active_ctx, '@type')] = ( self._compact_iri(active_ctx, value['@type'], vocab=True)) # alias @language elif '@language' in value: rval[self._compact_iri(active_ctx, '@language')] = ( value['@language']) # alias @value rval[self._compact_iri(active_ctx, '@value')] = value['@value'] return rval # value is a subject reference expanded_property = self._expand_iri( active_ctx, active_property, vocab=True) type_ = JsonLdProcessor.get_context_value( active_ctx, active_property, '@type') compacted = self._compact_iri( active_ctx, value['@id'], vocab=(type_ == '@vocab')) # compact to scalar if type_ in ['@id', '@vocab'] or expanded_property == '@graph': return compacted rval = {} rval[self._compact_iri(active_ctx, '@id')] = compacted return rval def _create_term_definition(self, active_ctx, local_ctx, term, defined): """ Creates a term definition during context processing. :param active_ctx: the current active context. :param local_ctx: the local context being processed. :param term: the key in the local context to define the mapping for. :param defined: a map of defining/defined keys to detect cycles and prevent double definitions. """ if term in defined: # term already defined if defined[term]: return # cycle detected raise JsonLdError( 'Cyclical context definition detected.', 'jsonld.CyclicalContext', { 'context': local_ctx, 'term': term }, code='cyclic IRI mapping') # now defining term defined[term] = False if _is_keyword(term): raise JsonLdError( 'Invalid JSON-LD syntax; keywords cannot be overridden.', 'jsonld.SyntaxError', {'context': local_ctx, 'term': term}, code='keyword redefinition') if term == '': raise JsonLdError( 'Invalid JSON-LD syntax; a term cannot be an empty string.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid term definition') # remove old mapping if term in active_ctx['mappings']: del active_ctx['mappings'][term] # get context term value value = local_ctx[term] # clear context entry if (value is None or (_is_object(value) and '@id' in value and value['@id'] is None)): active_ctx['mappings'][term] = None defined[term] = True return # convert short-hand value to object w/@id if _is_string(value): value = {'@id': value} if not _is_object(value): raise JsonLdError( 'Invalid JSON-LD syntax; @context property values must be ' 'strings or objects.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid term definition') # create new mapping mapping = active_ctx['mappings'][term] = {'reverse': False} if '@reverse' in value: if '@id' in value: raise JsonLdError( 'Invalid JSON-LD syntax; an @reverse term definition must ' 'not contain @id.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid reverse property') reverse = value['@reverse'] if not _is_string(reverse): raise JsonLdError( 'Invalid JSON-LD syntax; @context @reverse value must be ' 'a string.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid IRI mapping') # expand and add @id mapping id_ = self._expand_iri( active_ctx, reverse, vocab=True, base=False, local_ctx=local_ctx, defined=defined) if not _is_absolute_iri(id_): raise JsonLdError( 'Invalid JSON-LD syntax; @context @reverse value must be ' 'an absolute IRI or a blank node identifier.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid IRI mapping') mapping['@id'] = id_ mapping['reverse'] = True elif '@id' in value: id_ = value['@id'] if not _is_string(id_): raise JsonLdError( 'Invalid JSON-LD syntax; @context @id value must be a ' 'string.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid IRI mapping') if id_ != term: # add @id to mapping id_ = self._expand_iri( active_ctx, id_, vocab=True, base=False, local_ctx=local_ctx, defined=defined) if not _is_absolute_iri(id_) and not _is_keyword(id_): raise JsonLdError( 'Invalid JSON-LD syntax; @context @id value must be ' 'an absolute IRI, a blank node identifier, or a ' 'keyword.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid IRI mapping') mapping['@id'] = id_ if '@id' not in mapping: # see if the term has a prefix colon = term.find(':') if colon != -1: prefix = term[0:colon] if prefix in local_ctx: # define parent prefix self._create_term_definition( active_ctx, local_ctx, prefix, defined) # set @id based on prefix parent if active_ctx['mappings'].get(prefix) is not None: suffix = term[colon + 1:] mapping['@id'] = (active_ctx['mappings'][prefix]['@id'] + suffix) # term is an absolute IRI else: mapping['@id'] = term else: # non-IRIs MUST define @ids if @vocab not available if '@vocab' not in active_ctx: raise JsonLdError( 'Invalid JSON-LD syntax; @context terms must define ' 'an @id.', 'jsonld.SyntaxError', { 'context': local_ctx, 'term': term }, code='invalid IRI mapping') # prepend vocab to term mapping['@id'] = active_ctx['@vocab'] + term # IRI mapping now defined defined[term] = True if '@type' in value: type_ = value['@type'] if not _is_string(type_): raise JsonLdError( 'Invalid JSON-LD syntax; @context @type value must be ' 'a string.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid type mapping') if type_ != '@id' and type_ != '@vocab': # expand @type to full IRI type_ = self._expand_iri( active_ctx, type_, vocab=True, local_ctx=local_ctx, defined=defined) if not _is_absolute_iri(type_): raise JsonLdError( 'Invalid JSON-LD syntax; an @context @type value must ' 'be an absolute IRI.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid type mapping') if type_.startswith('_:'): raise JsonLdError( 'Invalid JSON-LD syntax; an @context @type values ' 'must be an IRI, not a blank node identifier.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid type mapping') # add @type to mapping mapping['@type'] = type_ if '@container' in value: container = value['@container'] if container not in ['@list', '@set', '@index', '@language']: raise JsonLdError( 'Invalid JSON-LD syntax; @context @container value ' 'must be one of the following: @list, @set, @index, or ' '@language.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid container mapping') if (mapping['reverse'] and container != '@index' and container != '@set' and container is not None): raise JsonLdError( 'Invalid JSON-LD syntax; @context @container value for ' 'an @reverse type definition must be @index or @set.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid reverse property') # add @container to mapping mapping['@container'] = container if '@language' in value and '@type' not in value: language = value['@language'] if not (language is None or _is_string(language)): raise JsonLdError( 'Invalid JSON-LD syntax; @context @language value must be ' 'a string or null.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid language mapping') # add @language to mapping if language is not None: language = language.lower() mapping['@language'] = language # disallow aliasing @context and @preserve id_ = mapping['@id'] if id_ == '@context' or id_ == '@preserve': raise JsonLdError( 'Invalid JSON-LD syntax; @context and @preserve ' 'cannot be aliased.', 'jsonld.SyntaxError', {'context': local_ctx}, code='invalid keyword alias') def _expand_iri( self, active_ctx, value, base=False, vocab=False, local_ctx=None, defined=None): """ Expands a string value to a full IRI. The string may be a term, a prefix, a relative IRI, or an absolute IRI. The associated absolute IRI will be returned. :param active_ctx: the current active context. :param value: the string value to expand. :param base: True to resolve IRIs against the base IRI, False not to. :param vocab: True to concatenate after @vocab, False not to. :param local_ctx: the local context being processed (only given if called during context processing). :param defined: a map for tracking cycles in context definitions (only given if called during context processing). :return: the expanded value. """ # already expanded if value is None or _is_keyword(value): return value # define dependency not if defined if (local_ctx and value in local_ctx and defined.get(value) is not True): self._create_term_definition(active_ctx, local_ctx, value, defined) if vocab and value in active_ctx['mappings']: mapping = active_ctx['mappings'].get(value) # value is explicitly ignored with None mapping if mapping is None: return None # value is a term return mapping['@id'] # split value into prefix:suffix if ':' in value: prefix, suffix = value.split(':', 1) # do not expand blank nodes (prefix of '_') or already-absolute # IRIs (suffix of '//') if prefix == '_' or suffix.startswith('//'): return value # prefix dependency not defined, define it if local_ctx and prefix in local_ctx: self._create_term_definition( active_ctx, local_ctx, prefix, defined) # use mapping if prefix is defined mapping = active_ctx['mappings'].get(prefix) if mapping: return mapping['@id'] + suffix # already absolute IRI return value # prepend vocab if vocab and '@vocab' in active_ctx: return active_ctx['@vocab'] + value # resolve against base rval = value if base: rval = prepend_base(active_ctx['@base'], rval) return rval def _find_context_urls(self, input_, urls, replace, base): """ Finds all @context URLs in the given JSON-LD input. :param input_: the JSON-LD input. :param urls: a map of URLs (url => False/@contexts). :param replace: True to replace the URLs in the given input with the @contexts from the urls map, False not to. :param base: the base URL to resolve relative URLs against. """ if _is_array(input_): for e in input_: self._find_context_urls(e, urls, replace, base) elif _is_object(input_): for k, v in input_.items(): if k != '@context': self._find_context_urls(v, urls, replace, base) continue # array @context if _is_array(v): length = len(v) for i in range(length): if _is_string(v[i]): url = prepend_base(base, v[i]) # replace w/@context if requested if replace: ctx = urls[url] if _is_array(ctx): # add flattened context v.pop(i) for e in reversed(ctx): v.insert(i, e) i += len(ctx) - 1 length = len(v) else: v[i] = ctx # @context URL found elif url not in urls: urls[url] = False # string @context elif _is_string(v): v = prepend_base(base, v) # replace w/@context if requested if replace: input_[k] = urls[v] # @context URL found elif v not in urls: urls[v] = False def _retrieve_context_urls(self, input_, cycles, load_document, base=''): """ Retrieves external @context URLs using the given document loader. Each instance of @context in the input that refers to a URL will be replaced with the JSON @context found at that URL. :param input_: the JSON-LD input with possible contexts. :param cycles: an object for tracking context cycles. :param load_document(url): the document loader. :param base: the base URL to resolve relative URLs against. :return: the result. """ if len(cycles) > MAX_CONTEXT_URLS: raise JsonLdError( 'Maximum number of @context URLs exceeded.', 'jsonld.ContextUrlError', {'max': MAX_CONTEXT_URLS}, code='loading remote context failed') # for tracking URLs to retrieve urls = {} # find all URLs in the given input self._find_context_urls(input_, urls, replace=False, base=base) # queue all unretrieved URLs queue = [] for url, ctx in urls.items(): if ctx is False: queue.append(url) # retrieve URLs in queue for url in queue: # check for context URL cycle if url in cycles: raise JsonLdError( 'Cyclical @context URLs detected.', 'jsonld.ContextUrlError', {'url': url}, code='recursive context inclusion') cycles_ = copy.deepcopy(cycles) cycles_[url] = True # retrieve URL try: remote_doc = load_document(url) ctx = remote_doc['document'] except Exception as cause: raise JsonLdError( 'Dereferencing a URL did not result in a valid JSON-LD ' 'context.', 'jsonld.ContextUrlError', {'url': url}, code='loading remote context failed', cause=cause) # parse string context as JSON if _is_string(ctx): try: ctx = json.loads(ctx) except Exception as cause: raise JsonLdError( 'Could not parse JSON from URL.', 'jsonld.ParseError', {'url': url}, code='loading remote context failed', cause=cause) # ensure ctx is an object if not _is_object(ctx): raise JsonLdError( 'Dereferencing a URL did not result in a valid JSON-LD ' 'object.', 'jsonld.InvalidUrl', {'url': url}, code='invalid remote context') # use empty context if no @context key is present if '@context' not in ctx: ctx = {'@context': {}} else: ctx = {'@context': ctx['@context']} # append context URL to context if given if remote_doc['contextUrl'] is not None: ctx['@context'] = JsonLdProcessor.arrayify(ctx['@context']) ctx['@context'].append(remote_doc['contextUrl']) # recurse self._retrieve_context_urls(ctx, cycles_, load_document, url) urls[url] = ctx['@context'] # replace all URLs in the input self._find_context_urls(input_, urls, replace=True, base=base) def _get_initial_context(self, options): """ Gets the initial context. :param options: the options to use. [base] the document base IRI. :return: the initial context. """ return { '@base': options['base'], 'mappings': {}, 'inverse': None } def _get_inverse_context(self, active_ctx): """ Generates an inverse context for use in the compaction algorithm, if not already generated for the given active context. :param active_ctx: the active context to use. :return: the inverse context. """ # inverse context already generated if active_ctx['inverse']: return active_ctx['inverse'] inverse = active_ctx['inverse'] = {} # handle default language default_language = active_ctx.get('@language', '@none') # create term selections for each mapping in the context, ordered by # shortest and then lexicographically least for term, mapping in sorted( active_ctx['mappings'].items(), key=cmp_to_key(_compare_shortest_least)): if mapping is None: continue # add term selection where it applies container = mapping.get('@container', '@none') # iterate over every IRI in the mapping iris = JsonLdProcessor.arrayify(mapping['@id']) for iri in iris: container_map = inverse.setdefault(iri, {}) entry = container_map.setdefault( container, {'@language': {}, '@type': {}}) # term is preferred for values using @reverse if mapping['reverse']: entry['@type'].setdefault('@reverse', term) # term is preferred for values using specific type elif '@type' in mapping: entry['@type'].setdefault(mapping['@type'], term) # term is preferred for values using specific language elif '@language' in mapping: language = mapping['@language'] if language is None: language = '@null' entry['@language'].setdefault(language, term) # term is preferred for values w/default language or not type # and no language else: # add an entry for the default language entry['@language'].setdefault(default_language, term) # add entries for no type and no language entry['@type'].setdefault('@none', term) entry['@language'].setdefault('@none', term) return inverse def _clone_active_context(self, active_ctx): """ Clones an active context, creating a child active context. :param active_ctx: the active context to clone. :return: a clone (child) of the active context. """ child = { '@base': active_ctx['@base'], 'mappings': copy.deepcopy(active_ctx['mappings']), 'inverse': None } if '@language' in active_ctx: child['@language'] = active_ctx['@language'] if '@vocab' in active_ctx: child['@vocab'] = active_ctx['@vocab'] return child # register the N-Quads RDF parser register_rdf_parser('application/nquads', JsonLdProcessor.parse_nquads) class JsonLdError(Exception): """ Base class for JSON-LD errors. """ def __init__(self, message, type_, details=None, code=None, cause=None): Exception.__init__(self, message) self.type = type_ self.details = details self.code = code self.cause = cause self.causeTrace = traceback.extract_tb(*sys.exc_info()[2:]) def __str__(self): if not hasattr(self, 'message'): return 'Unknown exception' rval = repr(self.message) rval += '\nType: ' + self.type if self.code: rval += '\nCode: ' + self.code if self.details: rval += '\nDetails: ' + repr(self.details) if self.cause: rval += '\nCause: ' + str(self.cause) rval += ''.join(traceback.format_list(self.causeTrace)) return rval class UniqueNamer(object): """ A UniqueNamer issues unique names, keeping track of any previously issued names. """ def __init__(self, prefix): """ Initializes a new UniqueNamer. :param prefix: the prefix to use (''). """ self.prefix = prefix self.counter = 0 self.existing = {} self.order = [] """ Gets the new name for the given old name, where if no old name is given a new name will be generated. :param [old_name]: the old name to get the new name for. :return: the new name. """ def get_name(self, old_name=None): # return existing old name if old_name and old_name in self.existing: return self.existing[old_name] # get next name name = self.prefix + str(self.counter) self.counter += 1 # save mapping if old_name is not None: self.existing[old_name] = name self.order.append(old_name) return name def is_named(self, old_name): """ Returns True if the given old name has already been assigned a new name. :param old_name: the old name to check. :return: True if the old name has been assigned a new name, False if not. """ return old_name in self.existing def permutations(elements): """ Generates all of the possible permutations for the given list of elements. :param elements: the list of elements to permutate. """ # begin with sorted elements elements.sort() # initialize directional info for permutation algorithm left = {} for v in elements: left[v] = True length = len(elements) last = length - 1 while True: yield elements # Calculate the next permutation using the Steinhaus-Johnson-Trotter # permutation algorithm. # get largest mobile element k # (mobile: element is greater than the one it is looking at) k, pos = None, 0 for i in range(length): e = elements[i] is_left = left[e] if((k is None or e > k) and ((is_left and i > 0 and e > elements[i - 1]) or (not is_left and i < last and e > elements[i + 1]))): k, pos = e, i # no more permutations if k is None: raise StopIteration # swap k and the element it is looking at swap = pos - 1 if left[k] else pos + 1 elements[pos], elements[swap] = elements[swap], k # reverse the direction of all elements larger than k for i in range(length): if elements[i] > k: left[elements[i]] = not left[elements[i]] def _compare_shortest_least(a, b): """ Compares two strings first based on length and then lexicographically. :param a: the first string. :param b: the second string. :return: -1 if a < b, 1 if a > b, 0 if a == b. """ rval = cmp(len(a), len(b)) if rval == 0: rval = cmp(a, b) return rval def _is_keyword(v): """ Returns whether or not the given value is a keyword. :param v: the value to check. :return: True if the value is a keyword, False if not. """ if not _is_string(v): return False return v in KEYWORDS def _is_object(v): """ Returns True if the given value is an Object. :param v: the value to check. :return: True if the value is an Object, False if not. """ return isinstance(v, dict) def _is_empty_object(v): """ Returns True if the given value is an empty Object. :param v: the value to check. :return: True if the value is an empty Object, False if not. """ return _is_object(v) and len(v) == 0 def _is_array(v): """ Returns True if the given value is an Array. :param v: the value to check. :return: True if the value is an Array, False if not. """ return isinstance(v, list) def _is_string(v): """ Returns True if the given value is a String. :param v: the value to check. :return: True if the value is a String, False if not. """ return isinstance(v, basestring) def _validate_type_value(v): """ Raises an exception if the given value is not a valid @type value. :param v: the value to check. """ # must be a string or empty object if (_is_string(v) or _is_empty_object(v)): return # must be an array is_valid = False if _is_array(v): # must contain only strings is_valid = True for e in v: if not _is_string(e): is_valid = False break if not is_valid: raise JsonLdError( 'Invalid JSON-LD syntax; "@type" value must a string, an array of ' 'strings, or an empty object.', 'jsonld.SyntaxError', {'value': v}, code='invalid type value') def _is_bool(v): """ Returns True if the given value is a Boolean. :param v: the value to check. :return: True if the value is a Boolean, False if not. """ return isinstance(v, bool) def _is_integer(v): """ Returns True if the given value is an Integer. :param v: the value to check. :return: True if the value is an Integer, False if not. """ return isinstance(v, Integral) def _is_double(v): """ Returns True if the given value is a Double. :param v: the value to check. :return: True if the value is a Double, False if not. """ return not isinstance(v, Integral) and isinstance(v, Real) def _is_numeric(v): """ Returns True if the given value is numeric. :param v: the value to check. :return: True if the value is numeric, False if not. """ try: float(v) return True except ValueError: return False def _is_subject(v): """ Returns True if the given value is a subject with properties. :param v: the value to check. :return: True if the value is a subject with properties, False if not. """ # Note: A value is a subject if all of these hold True: # 1. It is an Object. # 2. It is not a @value, @set, or @list. # 3. It has more than 1 key OR any existing key is not @id. rval = False if (_is_object(v) and '@value' not in v and '@set' not in v and '@list' not in v): rval = len(v) > 1 or '@id' not in v return rval def _is_subject_reference(v): """ Returns True if the given value is a subject reference. :param v: the value to check. :return: True if the value is a subject reference, False if not. """ # Note: A value is a subject reference if all of these hold True: # 1. It is an Object. # 2. It has a single key: @id. return (_is_object(v) and len(v) == 1 and '@id' in v) def _is_value(v): """ Returns True if the given value is a @value. :param v: the value to check. :return: True if the value is a @value, False if not. """ # Note: A value is a @value if all of these hold True: # 1. It is an Object. # 2. It has the @value property. return _is_object(v) and '@value' in v def _is_list(v): """ Returns True if the given value is a @list. :param v: the value to check. :return: True if the value is a @list, False if not. """ # Note: A value is a @list if all of these hold True: # 1. It is an Object. # 2. It has the @list property. return _is_object(v) and '@list' in v def _is_bnode(v): """ Returns True if the given value is a blank node. :param v: the value to check. :return: True if the value is a blank node, False if not. """ # Note: A value is a blank node if all of these hold True: # 1. It is an Object. # 2. If it has an @id key its value begins with '_:'. # 3. It has no keys OR is not a @value, @set, or @list. rval = False if _is_object(v): if '@id' in v: rval = v['@id'].startswith('_:') else: rval = (len(v) == 0 or not ('@value' in v or '@set' in v or '@list' in v)) return rval def _is_absolute_iri(v): """ Returns True if the given value is an absolute IRI, False if not. :param v: the value to check. :return: True if the value is an absolute IRI, False if not. """ return ':' in v class ActiveContextCache(object): """ An ActiveContextCache caches active contexts so they can be reused without the overhead of recomputing them. """ def __init__(self, size=100): self.order = deque() self.cache = {} self.size = size def get(self, active_ctx, local_ctx): key1 = json.dumps(active_ctx) key2 = json.dumps(local_ctx) return self.cache.get(key1, {}).get(key2) def set(self, active_ctx, local_ctx, result): if len(self.order) == self.size: entry = self.order.popleft() del self.cache[entry['activeCtx']][entry['localCtx']] key1 = json.dumps(active_ctx) key2 = json.dumps(local_ctx) self.order.append({'activeCtx': key1, 'localCtx': key2}) self.cache.setdefault(key1, {})[key2] = json.loads(json.dumps(result)) class VerifiedHTTPSConnection(HTTPSConnection): """ Used to verify SSL certificates when resolving URLs. Taken from: http://thejosephturner.com/blog/2011/03/19/https-\ certificate-verification-in-python-with-urllib2/ """ def connect(self): global _trust_root_certificates # overrides the version in httplib to do certificate verification sock = socket.create_connection((self.host, self.port), self.timeout) if self._tunnel_host: self.sock = sock self._tunnel() # wrap the socket using verification with trusted_root_certs self.sock = ssl.wrap_socket(sock, self.key_file, self.cert_file, cert_reqs=ssl.CERT_REQUIRED, ca_certs=_trust_root_certificates) class VerifiedHTTPSHandler(HTTPSHandler): """ Wraps urllib2 HTTPS connections enabling SSL certificate verification. """ def __init__(self, connection_class=VerifiedHTTPSConnection): self.specialized_conn_class = connection_class HTTPSHandler.__init__(self) def https_open(self, req): return self.do_open(self.specialized_conn_class, req) # the path to the system's default trusted root SSL certificates _trust_root_certificates = None _possible_trust_root_certificates = [ '/etc/ssl/certs/ca-certificates.crt', '~/Library/OpenSSL/certs/ca-certificates.crt', '/System/Library/OpenSSL/certs/ca-certificates.crt', ] for path in _possible_trust_root_certificates: path = os.path.expanduser(path) if os.path.exists(path): _trust_root_certificates = path break # FIXME: warn if not found? MacOS X uses keychain vs file. # Shared in-memory caches. _cache = { 'activeCtx': ActiveContextCache() }