API: make /api/v1/videos respect the 'local' parameter (#3567)

src/invidious.cr

@@ -34,6 +34,7 @@ require "protodec/utils"
 
 require "./invidious/database/*"
 require "./invidious/database/migrations/*"
+require "./invidious/http_server/*"
 require "./invidious/helpers/*"
 require "./invidious/yt_backend/*"
 require "./invidious/frontend/*"

src/invidious/http_server/utils.cr

@@ -0,0 +1,20 @@
+module Invidious::HttpServer
+  module Utils
+    extend self
+
+    def proxy_video_url(raw_url : String, *, region : String? = nil, absolute : Bool = false)
+      url = URI.parse(raw_url)
+
+      # Add some URL parameters
+      params = url.query_params
+      params["host"] = url.host.not_nil! # Should never be nil, in theory
+      params["region"] = region if !region.nil?
+
+      if absolute
+        return "#{HOST_URL}#{url.request_target}?#{params}"
+      else
+        return "#{url.request_target}?#{params}"
+      end
+    end
+  end
+end

src/invidious/jsonify/api_v1/video_json.cr

@@ -3,7 +3,7 @@ require "json"
 module Invidious::JSONify::APIv1
   extend self
 
-  def video(video : Video, json : JSON::Builder, *, locale : String?)
+  def video(video : Video, json : JSON::Builder, *, locale : String?, proxy : Bool = false)
     json.object do
       json.field "type", video.video_type
 
@@ -89,7 +89,14 @@ module Invidious::JSONify::APIv1
               # Not available on MPEG-4 Timed Text (`text/mp4`) streams (livestreams only)
               json.field "bitrate", fmt["bitrate"].as_i.to_s if fmt["bitrate"]?
 
+              if proxy
+                json.field "url", Invidious::HttpServer::Utils.proxy_video_url(
+                  fmt["url"].to_s, absolute: true
+                )
+              else
                 json.field "url", fmt["url"]
+              end
+
               json.field "itag", fmt["itag"].as_i.to_s
               json.field "type", fmt["mimeType"]
               json.field "clen", fmt["contentLength"]? || "-1"

src/invidious/routes/api/v1/videos.cr

@@ -6,6 +6,7 @@ module Invidious::Routes::API::V1::Videos
 
     id = env.params.url["id"]
     region = env.params.query["region"]?
+    proxy = {"1", "true"}.any? &.== env.params.query["local"]?
 
     begin
       video = get_video(id, region: region)
@@ -15,7 +16,9 @@ module Invidious::Routes::API::V1::Videos
       return error_json(500, ex)
     end
 
-    video.to_json(locale, nil)
+    return JSON.build do |json|
+      Invidious::JSONify::APIv1.video(video, json, locale: locale, proxy: proxy)
+    end
   end
 
   def self.captions(env)

src/invidious/routes/video_playback.cr

@@ -101,14 +101,8 @@ module Invidious::Routes::VideoPlayback
           env.response.headers["Access-Control-Allow-Origin"] = "*"
 
           if location = resp.headers["Location"]?
-            location = URI.parse(location)
-            location = "#{location.request_target}&host=#{location.host}"
-
-            if region
-              location += "&region=#{region}"
-            end
-
-            return env.redirect location
+            url = Invidious::HttpServer::Utils.proxy_video_url(location, region: region)
+            return env.redirect url
           end
 
           IO.copy(resp.body_io, env.response)