redirect: New member function for `struct uh_client`

cl->redirect(cl, 302, "/xx.html");
cl->redirect(cl, 301, "/%s.html", "xx");

Signed-off-by: Jianhui Zhao <jianhuizhao329@gmail.com>

src/client.c

@@ -62,6 +62,23 @@ static inline void client_header_end(struct uh_client *cl)
     cl->printf(cl, "\r\n");
 }
 
+static inline void client_redirect(struct uh_client *cl, int code, const char *fmt, ...)
+{
+    va_list arg;
+    const char *summary = ((code == 301) ? "Moved Permanently" : "Found");
+
+    assert((code == 301 || code == 302) && fmt);
+
+    cl->send_header(cl, code, summary, 0);
+    cl->printf(cl, "Location: ");
+    va_start(arg, fmt);
+    cl->vprintf(cl, fmt, arg);
+    va_end(arg);
+
+    cl->printf(cl, "\r\n\r\n");
+    cl->request_done(cl);
+}
+
 static void client_send_error(struct uh_client *cl, int code, const char *summary, const char *fmt, ...)
 {
     va_list arg;
@@ -479,6 +496,7 @@ void uh_accept_client(struct uh_server *srv, bool ssl)
     cl->send_header = client_send_header;
     cl->append_header = client_append_header;
     cl->header_end = client_header_end;
+    cl->redirect = client_redirect;
     cl->request_done = client_request_done;
 
     cl->send = client_send;

src/client.h

@@ -94,6 +94,7 @@ struct uh_client {
     void (*send_header)(struct uh_client *cl, int code, const char *summary, int length);
     void (*append_header)(struct uh_client *cl, const char *name, const char *value);
     void (*header_end)(struct uh_client *cl);
+    void (*redirect)(struct uh_client *cl, int code, const char *fmt, ...);
     void (*request_done)(struct uh_client *cl);
     
     void (*send)(struct uh_client *cl, const void *data, int len);

src/common.h

@@ -25,6 +25,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <ctype.h>
+#include <assert.h>
 #include <stdbool.h>
 #include <unistd.h>
 #include <inttypes.h>

src/file.c

@@ -227,10 +227,7 @@ struct path_info *uh_path_lookup(struct uh_client *cl, const char *url)
        is missing in the request url, redirect the client to the same
        url with trailing slash appended */
     if (!slash) {
-        cl->send_header(cl, 302, "Found", 0);
-        cl->printf(cl, "Location: %s%s%s\r\n\r\n", &path_phys[docroot_len],
-                query ? "?" : "", query ? query : "");
-        cl->request_done(cl);
+        cl->redirect(cl, 302, "%s%s%s", &path_phys[docroot_len], query ? "?" : "", query ? query : "");
         p.redirected = 1;
         return &p;
     }