Add invidious companion support (#4985)

* add support for invidious companion

* redirect latest_version and dash manifest to invidious companion

* fix Shadowing outer local variable `response`

* fixing condition for Content-Security-Policy

* throw error if inv_sig_helper and invidious_companion used same time

* Use sample instead of Random.rand

Co-authored-by: syeopite <70992037+syeopite@users.noreply.github.com>

* Remove debug puts functions

Co-authored-by: syeopite <70992037+syeopite@users.noreply.github.com>

* modify the description for config.example.yaml about invidious companion

* move config checks for invidious companion

* separate invidious_companion logic + better config.yaml config

* fixing "end" misplacement

* fix linting + use .empty?

* crystal handle decompression already by itself

* fix download function when invidious companion used

* fix linting

* invidious companion always used so always add CSP and redirect latest_version

* apply all the suggestions + rework invidious_companion parameter

* format watch.cr

* fix ameba Redundant use of `Object#to_s` in interpolation

* add ability for invidious companion to check request from invidious

* Better document private_url and public_url

* Better doc for invidious_companion_key

* !empty? to present?

* skip proxy for invidious companion

* fixing format

* missing ,

* add companion pooling http

* fix: don't use http proxy when sending requests to companion

* fix: logic where we want to have the invidious logic if companion is not used

* chore: remove baseurl usage from invidious companion

* chore: change from inv-sig-helper to companion for required playback

* fix: use puts + add warning for inv-sig-helper deprecated

---------

Co-authored-by: syeopite <70992037+syeopite@users.noreply.github.com>

src/invidious/yt_backend/connection_pool.cr

@@ -46,6 +46,43 @@ struct YoutubeConnectionPool
   end
 end
 
+struct CompanionConnectionPool
+  property pool : DB::Pool(HTTP::Client)
+
+  def initialize(capacity = 5, timeout = 5.0)
+    options = DB::Pool::Options.new(
+      initial_pool_size: 0,
+      max_pool_size: capacity,
+      max_idle_pool_size: capacity,
+      checkout_timeout: timeout
+    )
+
+    @pool = DB::Pool(HTTP::Client).new(options) do
+      companion = CONFIG.invidious_companion.sample
+      next make_client(companion.private_url, use_http_proxy: false)
+    end
+  end
+
+  def client(&)
+    conn = pool.checkout
+
+    begin
+      response = yield conn
+    rescue ex
+      conn.close
+
+      companion = CONFIG.invidious_companion.sample
+      conn = make_client(companion.private_url, use_http_proxy: false)
+
+      response = yield conn
+    ensure
+      pool.release(conn)
+    end
+
+    response
+  end
+end
+
 def add_yt_headers(request)
   request.headers.delete("User-Agent") if request.headers["User-Agent"] == "Crystal"
   request.headers["User-Agent"] ||= "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36"
@@ -61,9 +98,9 @@ def add_yt_headers(request)
   end
 end
 
-def make_client(url : URI, region = nil, force_resolve : Bool = false, force_youtube_headers : Bool = false)
+def make_client(url : URI, region = nil, force_resolve : Bool = false, force_youtube_headers : Bool = false, use_http_proxy : Bool = true)
   client = HTTP::Client.new(url)
-  client.proxy = make_configured_http_proxy_client() if CONFIG.http_proxy
+  client.proxy = make_configured_http_proxy_client() if CONFIG.http_proxy && use_http_proxy
 
   # Force the usage of a specific configured IP Family
   if force_resolve
@@ -78,8 +115,8 @@ def make_client(url : URI, region = nil, force_resolve : Bool = false, force_you
   return client
 end
 
-def make_client(url : URI, region = nil, force_resolve : Bool = false, &)
-  client = make_client(url, region, force_resolve: force_resolve)
+def make_client(url : URI, region = nil, force_resolve : Bool = false, use_http_proxy : Bool = true, &)
+  client = make_client(url, region, force_resolve: force_resolve, use_http_proxy: use_http_proxy)
   begin
     yield client
   ensure

src/invidious/yt_backend/youtube_api.cr

@@ -500,7 +500,11 @@ module YoutubeAPI
       data["params"] = params
     end
 
-    return self._post_json("/youtubei/v1/player", data, client_config)
+    if CONFIG.invidious_companion.present?
+      return self._post_invidious_companion("/youtubei/v1/player", data)
+    else
+      return self._post_json("/youtubei/v1/player", data, client_config)
+    end
   end
 
   ####################################################################
@@ -666,6 +670,49 @@ module YoutubeAPI
     return initial_data
   end
 
+  ####################################################################
+  # _post_invidious_companion(endpoint, data)
+  #
+  # Internal function that does the actual request to Invidious companion
+  # and handles errors.
+  #
+  # The requested data is an endpoint (URL without the domain part)
+  # and the data as a Hash object.
+  #
+  def _post_invidious_companion(
+    endpoint : String,
+    data : Hash,
+  ) : Hash(String, JSON::Any)
+    headers = HTTP::Headers{
+      "Content-Type"  => "application/json; charset=UTF-8",
+      "Authorization" => "Bearer #{CONFIG.invidious_companion_key}",
+    }
+
+    # Logging
+    LOGGER.debug("Invidious companion: Using endpoint: \"#{endpoint}\"")
+    LOGGER.trace("Invidious companion: POST data: #{data}")
+
+    # Send the POST request
+
+    begin
+      response = COMPANION_POOL.client &.post(endpoint, headers: headers, body: data.to_json)
+      body = response.body
+      if (response.status_code != 200)
+        raise Exception.new(
+          "Error while communicating with Invidious companion: \
+          status code: #{response.status_code} and body: #{body.dump}"
+        )
+      end
+    rescue ex
+      raise InfoException.new("Error while communicating with Invidious companion: " + (ex.message || "no extra info found"))
+    end
+
+    # Convert result to Hash
+    initial_data = JSON.parse(body).as_h
+
+    return initial_data
+  end
+
   ####################################################################
   # _decompress(body_io, headers)
   #