[gfycat] add "format" config key to select a video format

Possible values:
    - one of "mp4" (default), "webm", "gif", "webp", "mjpg"

If the selected format is not available, "mp4", "webm" and "gif"
(in that order) will be tried instead, until an available format
is found.

gallery_dl/extractor/gfycat.py

@@ -10,7 +10,6 @@
 
 from .common import Extractor, Message
 from .. import exception
-from ..cache import cache
 
 
 class GfycatExtractor(Extractor):
@@ -19,12 +18,20 @@ class GfycatExtractor(Extractor):
 
     def __init__(self, match):
         Extractor.__init__(self)
-        self.api = GfycatAPI(self)
         self.item_id = match.group(1)
+        self.formats = (self.config("format", "mp4"), "mp4", "webm", "gif")
+
+    def _select_format(self, gfycat):
+        for fmt in self.formats:
+            key = fmt + "Url"
+            if key in gfycat:
+                url = gfycat[key]
+                gfycat["extension"] = url[url.rfind(".")+1:]
+                return url
 
     @staticmethod
     def _clean(image):
-        for key in ("dislikes", "likes", "views"):
+        for key in ("dislikes", "likes", "views", "viewsNewEpoch"):
             del image[key]
         return image
 
@@ -35,60 +42,31 @@ class GfycatImageExtractor(GfycatExtractor):
     directory_fmt = ["{category}"]
     filename_fmt = "{category}_{gfyName}.{extension}"
     pattern = [r"(?:https?://)?(?:[a-z]+\.)?gfycat\.com/"
-               r"(?:detail/)?((?:[A-Z][a-z]+)+)"]
+               r"(?:(?:gifs/)?detail/|ifr/)?([A-Za-z]+)"]
     test = [
         ("https://gfycat.com/GrayGenerousCowrie", {
-            "url": "6a9eca1d7f4d9a2c590c92ec723fd63dc12140c6",
-            "keyword": "5887d4582c0b848440e4d21f0ff941927df18fa9",
-            "content": "4c2ccc216ac579271d136ed58453be75e776ddad",
+            "url": "e0b5e1d7223108249b15c3c7898dd358dbfae045",
+            "keyword": "77a65049939823071b532cbdb7dec77582c6ee5b",
+            "content": "3157cd8b3799205c5a0df98a7ee31aa85bf6491e",
         }),
         (("https://thumbs.gfycat.com/SillyLameIsabellinewheatear"
           "-size_restricted.gif"), {
-            "url": "96d61307fcf95e6d8e08bea66fd36a1a20b342f0",
+            "url": "13b32e6cc169d086577d7dd3fd36ee6cdbc02726",
         }),
         ("https://gfycat.com/detail/UnequaledHastyAnkole?tagname=aww", {
-            "url": "1063429f09463128ce93cfbd885229a4e9f1b383",
+            "url": "e24c9f69897fd223343782425a429c5cab6a768e",
         }),
     ]
 
     def items(self):
-        image = self._clean(self.api.gfycats(self.item_id))
+        gfycat = self._clean(self._get_info(self.item_id))
         yield Message.Version, 1
-        yield Message.Directory, image
-        # TODO: support other formats (gif, mp4)
-        yield Message.Url, image["webmUrl"], image
+        yield Message.Directory, gfycat
+        yield Message.Url, self._select_format(gfycat), gfycat
 
-
-class GfycatAPI():
-    """Minimal interface for the gfycat API"""
-    def __init__(self, extractor):
-        self.session = extractor.session
-
-    def gfycats(self, gfycat_id):
-        """Return information about a gfycat object"""
-        return self._call("gfycats/" + gfycat_id)["gfyItem"]
-
-    def authenticate(self):
-        """Authenticate the application by requesting an access token"""
-        token = self._authenticate_impl()
-        self.session.headers["Authorization"] = token
-
-    @cache(maxage=3600)
-    def _authenticate_impl(self):
-        """Actual authenticate implementation"""
-        url = "https://api.gfycat.com/v1/oauth/token"
-        data = {"grant_type": "client_credentials",
-                "client_id": "2_TFs1Nh",
-                "client_secret": ("IZ6qLQ0t7LzxY9P8Rm8Ao4S0sm91o-"
-                                  "o2yVkyO4QgDQK2QbVQNMuXks-M3fuwcs3r")}
-        response = self.session.post(url, json=data)
-        if response.status_code != 200:
-            raise exception.AuthenticationError()
-        return "Bearer " + response.json()["access_token"]
-
-    def _call(self, endpoint):
-        self.authenticate()
-        response = self.session.get("https://api.gfycat.com/v1/" + endpoint)
-        if response.status_code == 404:
+    def _get_info(self, gfycat_id):
+        url = "https://gfycat.com/cajax/get/" + gfycat_id
+        data = self.session.get(url).json()
+        if "error" in data:
             raise exception.NotFoundError()
-        return response.json()
+        return data["gfyItem"]