Add fallback downloader

bdfr/site_downloaders/download_factory.py

@@ -9,6 +9,7 @@ from bdfr.exceptions import NotADownloadableLinkError
 from bdfr.site_downloaders.base_downloader import BaseDownloader
 from bdfr.site_downloaders.direct import Direct
 from bdfr.site_downloaders.erome import Erome
+from bdfr.site_downloaders.fallback_downloaders.youtubedl_fallback import YoutubeDlFallback
 from bdfr.site_downloaders.gallery import Gallery
 from bdfr.site_downloaders.gfycat import Gfycat
 from bdfr.site_downloaders.imgur import Imgur
@@ -47,6 +48,8 @@ class DownloadFactory:
             return Streamable
         elif re.match(r'i\.redd\.it.*', sanitised_url):
             return Direct
+        elif YoutubeDlFallback.can_handle_link(sanitised_url):
+            return YoutubeDlFallback
         else:
             raise NotADownloadableLinkError(
                 f'No downloader module exists for url {url}')

bdfr/site_downloaders/fallback_downloaders/fallback_downloader.py

@@ -0,0 +1,15 @@
+#!/usr/bin/env python3
+# coding=utf-8
+
+from abc import ABC, abstractmethod
+
+from bdfr.site_downloaders.base_downloader import BaseDownloader
+
+
+class BaseFallbackDownloader(BaseDownloader, ABC):
+
+    @staticmethod
+    @abstractmethod
+    def can_handle_link(url: str) -> bool:
+        """Returns whether the fallback downloader can download this link"""
+        raise NotImplementedError

bdfr/site_downloaders/fallback_downloaders/youtubedl_fallback.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+# coding=utf-8
+
+import logging
+from typing import Optional
+
+import youtube_dl
+from praw.models import Submission
+
+from bdfr.resource import Resource
+from bdfr.site_authenticator import SiteAuthenticator
+from bdfr.site_downloaders.fallback_downloaders.fallback_downloader import BaseFallbackDownloader
+from bdfr.site_downloaders.youtube import Youtube
+
+logger = logging.getLogger(__name__)
+
+
+class YoutubeDlFallback(BaseFallbackDownloader, Youtube):
+    def __init__(self, post: Submission):
+        super(YoutubeDlFallback, self).__init__(post)
+
+    def find_resources(self, authenticator: Optional[SiteAuthenticator] = None) -> list[Resource]:
+        out = super()._download_video({})
+        return [out]
+
+    @staticmethod
+    def can_handle_link(url: str) -> bool:
+        yt_logger = logging.getLogger('youtube-dl')
+        yt_logger.setLevel(logging.CRITICAL)
+        with youtube_dl.YoutubeDL({
+            'logger': yt_logger,
+        }) as ydl:
+            try:
+                result = ydl.extract_info(url, download=False)
+                if result:
+                    return True
+            except youtube_dl.DownloadError as e:
+                logger.exception(e)
+                return False
+        return False