[redgifs][gfycat] provide fallback URLs (fixes #1962)

and extend the 'format' option

docs/configuration.rst

@@ -1237,16 +1237,20 @@ Description
 extractor.gfycat.format
 -----------------------
 Type
-    ``string``
+    * ``list`` of ``strings``
+    * ``string``
 Default
-    ``"mp4"``
+    ``["mp4", "webm", "mobile", "gif"]``
 Description
-    The name of the preferred animation format, which can be one of
-    ``"mp4"``, ``"webm"``, ``"gif"``, ``"webp"``, or ``"mjpg"``.
+    List of names of the preferred animation format, which can be
+    ``"mp4"``, ``"webm"``, ``"mobile"``, ``"gif"``, or ``"webp"``.
+
+    If a selected format is not available, the next one in the list will be
+    tried until an available format is found.
 
-    If the selected format is not available, ``"mp4"``, ``"webm"``
-    and ``"gif"`` (in that order) will be tried instead, until an
-    available format is found.
+    If the format is given as ``string``, it will be extended with
+    ``["mp4", "webm", "mobile", "gif"]``. Use a list with one element to
+    restrict it to only one possible format.
 
 
 extractor.hentaifoundry.include
@@ -1864,16 +1868,20 @@ Description
 extractor.redgifs.format
 ------------------------
 Type
-    ``string``
+    * ``list`` of ``strings``
+    * ``string``
 Default
-    ``"mp4"``
+    ``["mp4", "webm", "mobile", "gif"]``
 Description
-    The name of the preferred format, which can be one of
+    List of names of the preferred animation format, which can be
     ``"mp4"``, ``"webm"``, ``"gif"``, ``"webp"``, ``"mobile"``, or ``"mini"``.
 
-    If the selected format is not available, ``"mp4"``, ``"webm"``
-    and ``"gif"`` (in that order) will be tried instead, until an
-    available format is found.
+    If a selected format is not available, the next one in the list will be
+    tried until an available format is found.
+
+    If the format is given as ``string``, it will be extended with
+    ``["mp4", "webm", "mobile", "gif"]``. Use a list with one element to
+    restrict it to only one possible format.
 
 
 extractor.sankakucomplex.embeds

docs/gallery-dl.conf

@@ -107,7 +107,7 @@
         },
         "gfycat":
         {
-            "format": "mp4"
+            "format": ["mp4", "webm", "mobile", "gif"]
         },
         "hentaifoundry":
         {
@@ -222,7 +222,7 @@
         },
         "redgifs":
         {
-            "format": "mp4"
+            "format": ["mp4", "webm", "mobile", "gif"]
         },
         "sankakucomplex":
         {

gallery_dl/extractor/gfycat.py

@@ -22,7 +22,13 @@ class GfycatExtractor(Extractor):
     def __init__(self, match):
         Extractor.__init__(self, match)
         self.key = match.group(1).lower()
-        self.formats = (self.config("format", "mp4"), "mp4", "webm", "gif")
+
+        formats = self.config("format")
+        if formats is None:
+            formats = ("mp4", "webm", "mobile", "gif")
+        elif isinstance(formats, str):
+            formats = (formats, "mp4", "webm", "mobile", "gif")
+        self.formats = formats
 
     def items(self):
         metadata = self.metadata()
@@ -30,23 +36,25 @@ class GfycatExtractor(Extractor):
             if "gfyName" not in gfycat:
                 self.log.warning("Skipping '%s' (malformed)", gfycat["gfyId"])
                 continue
-            url = self._select_format(gfycat)
+            url = self._process(gfycat)
             gfycat.update(metadata)
-            gfycat["date"] = text.parse_timestamp(gfycat.get("createDate"))
             yield Message.Directory, gfycat
             yield Message.Url, url, gfycat
 
-    def _select_format(self, gfyitem):
+    def _process(self, gfycat):
+        gfycat["_fallback"] = formats = self._formats(gfycat)
+        gfycat["date"] = text.parse_timestamp(gfycat.get("createDate"))
+        return next(formats, "")
+
+    def _formats(self, gfycat):
         for fmt in self.formats:
             key = fmt + "Url"
-            if key in gfyitem:
-                url = gfyitem[key]
+            if key in gfycat:
+                url = gfycat[key]
                 if url.startswith("http:"):
                     url = "https" + url[4:]
-                gfyitem["extension"] = url.rpartition(".")[2]
-                return url
-        gfyitem["extension"] = ""
-        return ""
+                gfycat["extension"] = url.rpartition(".")[2]
+                yield url
 
     def metadata(self):
         return {}
@@ -146,8 +154,7 @@ class GfycatImageExtractor(GfycatExtractor):
             if "gfyName" not in gfycat:
                 self.log.warning("Skipping '%s' (malformed)", gfycat["gfyId"])
                 return
-            url = self._select_format(gfycat)
-            gfycat["date"] = text.parse_timestamp(gfycat.get("createDate"))
+            url = self._process(gfycat)
             yield Message.Directory, gfycat
             yield Message.Url, url, gfycat