[http] Support for extracting artwork url from within StreamUrl field

src/http.c

@@ -36,6 +36,7 @@
 #include <libavutil/opt.h>
 
 #include <event2/event.h>
+#include <event2/keyvalq_struct.h>
 
 #include <curl/curl.h>
 
@@ -193,6 +194,41 @@ http_client_request(struct http_client_ctx *ctx, struct http_client_session *ses
   return 0;
 }
 
+int
+http_form_urldecode(struct keyval *kv, const char *uri)
+{
+  struct evhttp_uri *ev_uri = NULL;
+  struct evkeyvalq ev_query = { 0 };
+  struct evkeyval *param;
+  const char *query;
+  int ret;
+
+  ev_uri = evhttp_uri_parse_with_flags(uri, EVHTTP_URI_NONCONFORMANT);
+  if (!ev_uri)
+    return -1;
+
+  query = evhttp_uri_get_query(ev_uri);
+  if (!query)
+    goto error;
+
+  ret = evhttp_parse_query_str(query, &ev_query);
+  if (ret < 0)
+    goto error;
+
+  // musl libc doesn't have sys/queue.h so don't use TAILQ_FOREACH
+  for (param = ev_query.tqh_first; param; param = param->next.tqe_next)
+    keyval_add(kv, param->key, param->value);
+
+  evhttp_uri_free(ev_uri);
+  evhttp_clear_headers(&ev_query);
+  return 0;
+
+ error:
+  evhttp_uri_free(ev_uri);
+  evhttp_clear_headers(&ev_query);
+  return -1;
+}
+
 char *
 http_form_urlencode(struct keyval *kv)
 {

src/http.h

@@ -86,6 +86,14 @@ http_client_request(struct http_client_ctx *ctx, struct http_client_session *ses
 char *
 http_form_urlencode(struct keyval *kv);
 
+/* The reverse of http_form_urlencode, except takes a full url as input.
+ *
+ * @param kv keyval struct allocated by caller where values will be added
+ * @param url with the query to decode
+ * @return 0 if ok, otherwise -1
+ */
+int
+http_form_urldecode(struct keyval *kv, const char *uri);
 
 /* Returns a newly allocated string with the first stream in the m3u given in
  * url. If url is not a m3u, the string will be a copy of url.

src/inputs/http.c

@@ -173,8 +173,9 @@ streamurl_process(struct input_metadata *metadata, const char *url)
 {
   struct http_client_ctx client = { 0 };
   struct keyval kv = { 0 };
-  struct evbuffer *evbuf;
+  struct evbuffer *evbuf = NULL;
   const char *content_type;
+  const char *artwork_url;
   char *body;
   int ret;
 
@@ -186,6 +187,21 @@ streamurl_process(struct input_metadata *metadata, const char *url)
       return -1;
     }
 
+  // If the StreamUrl contains a keyword followed by the actual url, e.g. http://metadata.cdnstream1.com/?yadayada&ALBUM_ART=https%3A%2F%2Fis1-ssl.mzstatic.com%2Fimage%2Fthumb%2FMusic%2F11%2Fcc%2F21%2Fmzi.nepwiuir.jpg
+  if (streamurl_map[0].words)
+    {
+      ret = http_form_urldecode(&kv, url);
+      if (ret < 0)
+	return -1;
+
+      artwork_url = keyval_get(&kv, streamurl_map[0].words);
+      metadata->artwork_url = safe_strdup(artwork_url);
+      keyval_clear(&kv);
+
+      if (metadata->artwork_url)
+	goto out;
+    }
+
   DPRINTF(E_DBG, L_PLAYER, "Downloading StreamUrl resource '%s'\n", url);
 
   CHECK_NULL(L_PLAYER, evbuf = evbuffer_new());
@@ -219,7 +235,8 @@ streamurl_process(struct input_metadata *metadata, const char *url)
 
  out:
   keyval_clear(&kv);
-  evbuffer_free(evbuf);
+  if (evbuf)
+    evbuffer_free(evbuf);
   streamurl_settings_unload();
   return ret;
 }