videos: handle different JSON structs being present in cache

src/invidious/videos.cr

@@ -7,6 +7,16 @@ end
 struct Video
   include DB::Serializable
 
+  # Version of the JSON structure
+  # It prevents us from loading an incompatible version from cache
+  # (either newer or older, if instances with different versions run
+  # concurrently, e.g during a version upgrade rollout).
+  #
+  # NOTE: don't forget to bump this number if any change is made to
+  # the `params` structure in videos/parser.cr!!!
+  #
+  SCHEMA_VERSION = 2
+
   property id : String
 
   @[DB::Field(converter: Video::JSONConverter)]
@@ -55,6 +65,10 @@ struct Video
     return VideoType.parse?(video_type) || VideoType::Video
   end
 
+  def schema_version : Int
+    return info["version"]?.try &.as_i || 1
+  end
+
   def published : Time
     return info["published"]?
       .try { |t| Time.parse(t.as_s, "%Y-%m-%d", Time::Location::UTC) } || Time.utc
@@ -326,7 +340,8 @@ def get_video(id, refresh = true, region = nil, force_refresh = false)
     if (refresh &&
        (Time.utc - video.updated > 10.minutes) ||
        (video.premiere_timestamp.try &.< Time.utc)) ||
-       force_refresh
+       force_refresh ||
+       video.schema_version != Video::SCHEMA_VERSION # cache control
       begin
         video = fetch_video(id, region)
         Invidious::Database::Videos.update(video)

src/invidious/videos/parser.cr

@@ -71,6 +71,7 @@ def extract_video_info(video_id : String, proxy_region : String? = nil, context_
     # Stop here if video is not a scheduled livestream
     if playability_status != "LIVE_STREAM_OFFLINE"
       return {
+        "version" => JSON::Any.new(Video::SCHEMA_VERSION.to_i64),
         "reason"  => JSON::Any.new(reason),
       }
     end
@@ -121,6 +122,9 @@ def extract_video_info(video_id : String, proxy_region : String? = nil, context_
     params[f] = player_response[f] if player_response[f]?
   end
 
+  # Data structure version, for cache control
+  params["version"] = JSON::Any.new(Video::SCHEMA_VERSION.to_i64)
+
   return params
 end