Fix problems with iTunes 12.1, see issue #100

- don't announce group support to iTunes
    - support for absolute http url streaming requests

src/httpd_daap.c

@@ -822,7 +822,15 @@ daap_reply_server_info(struct evhttp_request *req, struct evbuffer *evbuf, char
   dmap_add_int(content, "aeSV", apro);       // com.apple.itunes.music-sharing-version (determines if itunes shows share types)
 
   dmap_add_short(content, "ated", 7);        // daap.supportsextradata
-  dmap_add_short(content, "asgr", 3);        // daap.supportsgroups
+
+  /* Sub-optimal user-agent sniffing to solve the problem that iTunes 12.1
+   * does not work if we announce support for groups.
+   */ 
+  ua = evhttp_find_header(headers, "User-Agent");
+  if (ua && (strncmp(ua, "iTunes", strlen("iTunes")) == 0))
+    dmap_add_short(content, "asgr", 0);      // daap.supportsgroups (1=artists, 2=albums, 3=both)
+  else
+    dmap_add_short(content, "asgr", 3);      // daap.supportsgroups (1=artists, 2=albums, 3=both)
 
 //  dmap_add_long(content, "asse", 0x80000); // unknown - used by iTunes
 
@@ -857,6 +865,9 @@ daap_reply_server_info(struct evhttp_request *req, struct evbuffer *evbuf, char
 
   dmap_add_int(content, "msdc", 1);          // dmap.databasescount
 
+//  dmap_add_int(content, "mstc", );          // dmap.utctime
+//  dmap_add_int(content, "msto", );          // dmap.utcoffset
+
   // Create container
   dmap_add_container(evbuf, "msrv", EVBUFFER_LENGTH(content));
   evbuffer_add_buffer(evbuf, content);
@@ -2331,14 +2342,9 @@ daap_reply_extra_data(struct evhttp_request *req, struct evbuffer *evbuf, char *
 static int
 daap_stream(struct evhttp_request *req, struct evbuffer *evbuf, char **uri, struct evkeyvalq *query, const char *ua)
 {
-  struct daap_session *s;
   int id;
   int ret;
 
-  s = daap_session_find(req, query, evbuf);
-  if (!s)
-    return -1;
-
   ret = safe_atoi32(uri[3], &id);
   if (ret < 0)
     evhttp_send_error(req, HTTP_BADREQUEST, "Bad Request");
@@ -2348,6 +2354,23 @@ daap_stream(struct evhttp_request *req, struct evbuffer *evbuf, char **uri, stru
   return ret;
 }
 
+static char *
+uri_relative(char *uri, const char *protocol)
+{
+  char *ret;
+
+  if (strncmp(uri, protocol, strlen(protocol)) != 0)
+    return NULL;
+
+  ret = strchr(uri + strlen(protocol), '/');
+  if (!ret)
+    {
+      DPRINTF(E_LOG, L_DAAP, "Malformed DAAP Request URI '%s'\n", uri);
+      return NULL;
+    }
+
+  return ret;
+}
 
 static char *
 daap_fix_request_uri(struct evhttp_request *req, char *uri)
@@ -2356,25 +2379,21 @@ daap_fix_request_uri(struct evhttp_request *req, char *uri)
 
   /* iTunes 9 gives us an absolute request-uri like
    *  daap://10.1.1.20:3689/server-info
+   * iTunes 12.1 gives us an absolute request-uri for streaming like
+   *  http://10.1.1.20:3689/databases/1/items/1.mp3
    */
 
-  if (strncmp(uri, "daap://", strlen("daap://")) != 0)
+  if ( (ret = uri_relative(uri, "daap://")) || (ret = uri_relative(uri, "http://")) )
-    return uri;
-
-  /* Clear the proxy request flag set by evhttp
-   * due to the request URI being absolute.
-   * It has side-effects on Connection: keep-alive
-   */
-  req->flags &= ~EVHTTP_PROXY_REQUEST;
-
-  ret = strchr(uri + strlen("daap://"), '/');
-  if (!ret)
     {
-      DPRINTF(E_LOG, L_DAAP, "Malformed DAAP Request URI '%s'\n", uri);
+      /* Clear the proxy request flag set by evhttp
-      return NULL;
+       * due to the request URI being absolute.
+       * It has side-effects on Connection: keep-alive
+       */
+      req->flags &= ~EVHTTP_PROXY_REQUEST;
+      return ret;
     }
 
-  return ret;
+  return uri;
 }