[weasyl] Fix favourites extractor and add support for the readable URL format

gallery_dl/extractor/weasyl.py

@@ -159,15 +159,25 @@ def items(self):
 
 class WeasylFavoriteExtractor(WeasylExtractor):
     subcategory = "favorite"
-    directory_fmt = ("{category}", "{owner_login}", "Favorites")
-    pattern = BASE_PATTERN + r"favorites\?userid=(\d+)"
+    directory_fmt = ("{category}", "{user}", "Favorites")
+    pattern = BASE_PATTERN + r"favorites(?:\?userid=(\d+)|\/([\w~-]+))"
     example = "https://www.weasyl.com/favorites?userid=12345"
 
     def __init__(self, match):
         WeasylExtractor.__init__(self, match)
         self.userid = match.group(1)
+        self.username = match.group(2)
 
     def items(self):
+        if self.userid is None and self.username is not None:
+            new_url = self.root + "/favorites/{}".format(self.username)
+            page = self.request(new_url).text
+            self.userid = text.extr(
+                page,
+                '<a class="more" href="/favorites?userid=',
+                '&amp'
+            )
+
         owner_login = lastid = None
         url = self.root + "/favorites"
         params = {
@@ -182,16 +192,18 @@ def items(self):
             if not owner_login:
                 owner_login = text.extr(page, '<a href="/~', '"')
 
+            new_posts = False
             for submitid in text.extract_iter(page, "/submissions/", "/", pos):
                 if submitid == lastid:
                     continue
+                new_posts = True
                 lastid = submitid
                 submission = self.request_submission(submitid)
                 if self.populate_submission(submission):
                     submission["user"] = owner_login
                     yield Message.Directory, submission
                     yield Message.Url, submission["url"], submission
 
-            if "&amp;nextid=" not in page:
+            if not new_posts:
                 return
             params["nextid"] = submitid

test/results/weasyl.py

@@ -92,4 +92,11 @@
     "#count"   : ">= 5",
 },
 
+{
+    "#url"     : "https://www.weasyl.com/favorites/furoferre",
+    "#category": ("", "weasyl", "favorite"),
+    "#class"   : weasyl.WeasylFavoriteExtractor,
+    "#count"   : ">= 5",
+}
+
 )