Add audio files and audio embeds

Backend/Embeds.py

@@ -19,6 +19,7 @@ DescriptionExcerptLength = 200
 DefaultDescriptions = {
     "directory": "A directory on SaraView.",
     "video": "A video on SaraView.",
+    "audio": "Audio on SaraView.",
     "image": "An image on SaraView.",
     "note": "A note on SaraView.",
     "file": "A file on SaraView.",
@@ -89,6 +90,19 @@ def BuildOgTags(RootName: str, RelativePath: str, IsDirectoryUrl: bool, BaseUrl:
         Tags.append(_MetaTag("og:video:secure_url", MediaUrl))
         Tags.append(_MetaTag("og:video:type", GetMimeType(EntryPath)))
         Tags.append(_MetaTag("og:description", DefaultDescriptions["video"]))
+    elif FileType == "audio":
+        # og:audio is the standard tag, but Discord doesn't play it. Discord
+        # does play og:video in an HTML5 player, which handles audio-only
+        # files too, so the audio is offered as both.
+        Tags.append(_MetaTag("og:type", "video.other"))
+        Tags.append(_MetaTag("og:audio", MediaUrl))
+        Tags.append(_MetaTag("og:audio:secure_url", MediaUrl))
+        Tags.append(_MetaTag("og:audio:type", GetMimeType(EntryPath)))
+        Tags.append(_MetaTag("og:video", MediaUrl))
+        Tags.append(_MetaTag("og:video:url", MediaUrl))
+        Tags.append(_MetaTag("og:video:secure_url", MediaUrl))
+        Tags.append(_MetaTag("og:video:type", GetMimeType(EntryPath)))
+        Tags.append(_MetaTag("og:description", DefaultDescriptions["audio"]))
     elif FileType == "image":
         Tags.append(_MetaTag("og:type", "website"))
         Tags.append(_MetaTag("og:image", MediaUrl))