Fix subtitles proxying, every URL is unique and beautiful

main.py

@@ -415,7 +415,15 @@ async def video_channels__about(domain, name):
 @app.route("/<string:domain>/videos/watch/<string:id>/<string:lang>.vtt")
 async def subtitles(domain, id, lang):
     try:
-        return peertube.video_captions_download(domain, id, lang)
+        captions = peertube.video_captions(domain, id)
+        print(captions)
+        for entry in captions["data"]:
+            if entry["language"]["id"] == lang: return peertube.video_captions_download(domain, entry["captionPath"].split('/')[-1])
+        return await render_template(
+            "error.html",
+            error_number = "404",
+            error_reason = "This video has no subtitles/captions inthe requested language"
+        ), 404
     except Exception as e:
         return await render_template(
             "error.html",

peertube.py

@@ -26,10 +26,11 @@ def video_captions(domain, id):
     url = "https://" + domain + "/api/v1/videos/" + id + "/captions"
     return json.loads(requests.get(url).text)
 
-def video_captions_download(domain, id, lang):
+def video_captions_download(domain, caption_id):
     # URL is hardcoded to prevent further proxying. URL may change with updates, see captions API
     # eg. https://kolektiva.media/api/v1/videos/9c9de5e8-0a1e-484a-b099-e80766180a6d/captions
-    url = "https://" + domain + "/lazy-static/video-captions/" + id + '-' + lang + ".vtt"
+    # TODO: What if the captionPath doesn't follow this format on an instance? Should we really proxy ANYTHING returned by API?
+    url = "https://" + domain + "/lazy-static/video-captions/" + caption_id
     return requests.get(url).text
 
 def search(domain, term, start=0, count=10):