Youtube api improvements (#2277)

* Put youtube API functions under the YoutubeAPI namespace

* Implement the following endpoints:
  - `next`
  - `player`
  - `resolve_url`

* Allow a ClientConfig to be passed to YoutubeAPI endpoint handlers.

* Add constants for many new clients

* Fix documentation of YoutubeAPI.browse(): Comments and search
  result aren't returned by the browse() endpoint but by the next()
  and search() endpoints, respectively.

* Accept gzip compressed data, to help save on bandwidth

* Add debug/trace logging

* Other minor fixes

src/invidious/channels/playlists.cr

@@ -1,6 +1,6 @@
 def fetch_channel_playlists(ucid, author, continuation, sort_by)
   if continuation
-    response_json = request_youtube_api_browse(continuation)
+    response_json = YoutubeAPI.browse(continuation)
     continuationItems = response_json["onResponseReceivedActions"]?
       .try &.[0]["appendContinuationItemsAction"]["continuationItems"]
 

src/invidious/channels/videos.cr

@@ -61,7 +61,7 @@ def get_channel_videos_response(ucid, page = 1, auto_generated = nil, sort_by =
   continuation = produce_channel_videos_continuation(ucid, page,
     auto_generated: auto_generated, sort_by: sort_by, v2: true)
 
-  return request_youtube_api_browse(continuation)
+  return YoutubeAPI.browse(continuation)
 end
 
 def get_60_videos(ucid, author, page, auto_generated, sort_by = "newest")

src/invidious/helpers/youtube_api.cr

@@ -2,60 +2,224 @@
 # This file contains youtube API wrappers
 #
 
-# Hard-coded constants required by the API
-HARDCODED_API_KEY     = "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8"
-HARDCODED_CLIENT_VERS = "2.20210330.08.00"
+module YoutubeAPI
+  extend self
+
+  # Enumerate used to select one of the clients supported by the API
+  enum ClientType
+    Web
+    WebEmbed
+    WebMobile
+    WebAgeBypass
+    Android
+    AndroidEmbed
+    AndroidAgeBypass
+  end
+
+  # List of hard-coded values used by the different clients
+  HARDCODED_CLIENTS = {
+    ClientType::Web => {
+      name:    "WEB",
+      version: "2.20210721.00.00",
+      api_key: "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8",
+      screen:  "WATCH_FULL_SCREEN",
+    },
+    ClientType::WebEmbed => {
+      name:    "WEB_EMBEDDED_PLAYER", # 56
+      version: "1.20210721.1.0",
+      api_key: "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8",
+      screen:  "EMBED",
+    },
+    ClientType::WebMobile => {
+      name:    "MWEB",
+      version: "2.20210726.08.00",
+      api_key: "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8",
+      screen:  "", # None
+    },
+    ClientType::WebAgeBypass => {
+      name:    "WEB",
+      version: "2.20210721.00.00",
+      api_key: "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8",
+      screen:  "EMBED",
+    },
+    ClientType::Android => {
+      name:    "ANDROID",
+      version: "16.20",
+      api_key: "AIzaSyA8eiZmM1FaDVjRy-df2KTyQ_vz_yYM39w",
+      screen:  "", # ??
+    },
+    ClientType::AndroidEmbed => {
+      name:    "ANDROID_EMBEDDED_PLAYER", # 55
+      version: "16.20",
+      api_key: "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8",
+      screen:  "", # None?
+    },
+    ClientType::AndroidAgeBypass => {
+      name:    "ANDROID", # 3
+      version: "16.20",
+      api_key: "AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8",
+      screen:  "EMBED",
+    },
+  }
 
   ####################################################################
-# make_youtube_api_context(region)
+  # struct ClientConfig
+  #
+  # Data structure used to pass a client configuration to the different
+  # API endpoints handlers.
+  #
+  # Use case examples:
+  #
+  # ```
+  # # Get Norwegian search results
+  # conf_1 = ClientConfig.new(region: "NO")
+  # YoutubeAPI::search("Kollektivet", params: "", client_config: conf_1)
+  #
+  # # Use the Android client to request video streams URLs
+  # conf_2 = ClientConfig.new(client_type: ClientType::Android)
+  # YoutubeAPI::player(video_id: "dQw4w9WgXcQ", client_config: conf_2)
+  #
+  # # Proxy request through russian proxies
+  # conf_3 = ClientConfig.new(proxy_region: "RU")
+  # YoutubeAPI::next({video_id: "dQw4w9WgXcQ"}, client_config: conf_3)
+  # ```
+  #
+  struct ClientConfig
+    # Type of client to emulate.
+    # See `enum ClientType` and `HARDCODED_CLIENTS`.
+    property client_type : ClientType
+
+    # Region to provide to youtube, e.g to alter search results
+    # (this is passed as the `gl` parmeter).
+    property region : String | Nil
+
+    # ISO code of country where the proxy is located.
+    # Used in case of geo-restricted videos.
+    property proxy_region : String | Nil
+
+    # Initialization function
+    def initialize(
+      *,
+      @client_type = ClientType::Web,
+      @region = "US",
+      @proxy_region = nil
+    )
+    end
+
+    # Getter functions that provides easy access to hardcoded clients
+    # parameters (name/version strings and related API key)
+    def name : String
+      HARDCODED_CLIENTS[@client_type][:name]
+    end
+
+    # :ditto:
+    def version : String
+      HARDCODED_CLIENTS[@client_type][:version]
+    end
+
+    # :ditto:
+    def api_key : String
+      HARDCODED_CLIENTS[@client_type][:api_key]
+    end
+
+    # :ditto:
+    def screen : String
+      HARDCODED_CLIENTS[@client_type][:screen]
+    end
+
+    # Convert to string, for logging purposes
+    def to_s
+      return {
+        client_type:  self.name,
+        region:       @region,
+        proxy_region: @proxy_region,
+      }.to_s
+    end
+  end
+
+  # Default client config, used if nothing is passed
+  DEFAULT_CLIENT_CONFIG = ClientConfig.new
+
+  ####################################################################
+  # make_context(client_config)
   #
   # Return, as a Hash, the "context" data required to request the
   # youtube API endpoints.
   #
-def make_youtube_api_context(region : String | Nil) : Hash
-  return {
+  private def make_context(client_config : ClientConfig | Nil) : Hash
+    # Use the default client config if nil is passed
+    client_config ||= DEFAULT_CLIENT_CONFIG
+
+    client_context = {
       "client" => {
         "hl"            => "en",
-      "gl"            => region || "US", # Can't be empty!
-      "clientName"    => "WEB",
-      "clientVersion" => HARDCODED_CLIENT_VERS,
+        "gl"            => client_config.region || "US", # Can't be empty!
+        "clientName"    => client_config.name,
+        "clientVersion" => client_config.version,
+        "thirdParty"    => {
+          "embedUrl" => "", # Placeholder
+        },
       },
     }
+
+    # Add some more context if it exists in the client definitions
+    if !client_config.screen.empty?
+      client_context["client"]["clientScreen"] = client_config.screen
+    end
+
+    # Replacing/removing the placeholder is easier than trying to
+    # merge two different Hash structures.
+    if client_config.screen == "EMBED"
+      client_context["client"]["thirdParty"] = {
+        "embedUrl" => "https://www.youtube.com/embed/dQw4w9WgXcQ",
+      }
+    else
+      client_context["client"].delete("thirdParty")
+    end
+
+    return client_context
   end
 
   ####################################################################
-# request_youtube_api_browse(continuation)
-# request_youtube_api_browse(browse_id, params, region)
+  # browse(continuation, client_config?)
+  # browse(browse_id, params, client_config?)
   #
   # Requests the youtubei/v1/browse endpoint with the required headers
   # and POST data in order to get a JSON reply in english that can
   # be easily parsed.
   #
-# The region can be provided, default is US.
+  # Both forms can take an optional ClientConfig parameter (see
+  # `struct ClientConfig` above for more details).
   #
   # The requested data can either be:
   #
   #  - A continuation token (ctoken). Depending on this token's
-#    contents, the returned data can be comments, playlist videos,
-#    search results, channel community tab, ...
+  #    contents, the returned data can be playlist videos, channel
+  #    community tab content, channel info, ...
   #
   #  - A playlist ID (parameters MUST be an empty string)
   #
-def request_youtube_api_browse(continuation : String)
+  def browse(continuation : String, client_config : ClientConfig | Nil = nil)
     # JSON Request data, required by the API
     data = {
-    "context"      => make_youtube_api_context("US"),
+      "context"      => self.make_context(client_config),
       "continuation" => continuation,
     }
 
-  return _youtube_api_post_json("/youtubei/v1/browse", data)
+    return self._post_json("/youtubei/v1/browse", data, client_config)
   end
 
-def request_youtube_api_browse(browse_id : String, params : String, region : String = "US")
+  # :ditto:
+  def browse(
+    browse_id : String,
+    *, # Force the following paramters to be passed by name
+    params : String,
+    client_config : ClientConfig | Nil = nil
+  )
     # JSON Request data, required by the API
     data = {
       "browseId" => browse_id,
-    "context"  => make_youtube_api_context(region),
+      "context"  => self.make_context(client_config),
     }
 
     # Append the additionnal parameters if those were provided
@@ -64,11 +228,138 @@ def request_youtube_api_browse(browse_id : String, params : String, region : Str
       data["params"] = params
     end
 
-  return _youtube_api_post_json("/youtubei/v1/browse", data)
+    return self._post_json("/youtubei/v1/browse", data, client_config)
   end
 
   ####################################################################
-# request_youtube_api_search(search_query, params, region)
+  # next(continuation, client_config?)
+  # next(data, client_config?)
+  #
+  # Requests the youtubei/v1/next endpoint with the required headers
+  # and POST data in order to get a JSON reply in english that can
+  # be easily parsed.
+  #
+  # Both forms can take an optional ClientConfig parameter (see
+  # `struct ClientConfig` above for more details).
+  #
+  # The requested data can be:
+  #
+  #  - A continuation token (ctoken). Depending on this token's
+  #    contents, the returned data can be videos comments,
+  #    their replies, ... In this case, the string must be passed
+  #    directly to the function. E.g:
+  #
+  #    ```
+  #    YoutubeAPI::next("ABCDEFGH_abcdefgh==")
+  #    ```
+  #
+  #  - Arbitrary parameters, in Hash form. See examples below for
+  #    known examples of arbitrary data that can be passed to YouTube:
+  #
+  #    ```
+  #    # Get the videos related to a specific video ID
+  #    YoutubeAPI::next({"videoId" => "dQw4w9WgXcQ"})
+  #
+  #    # Get a playlist video's details
+  #    YoutubeAPI::next({
+  #      "videoId"    => "9bZkp7q19f0",
+  #      "playlistId" => "PL_oFlvgqkrjUVQwiiE3F3k3voF4tjXeP0",
+  #    })
+  #    ```
+  #
+  def next(continuation : String, *, client_config : ClientConfig | Nil = nil)
+    # JSON Request data, required by the API
+    data = {
+      "context"      => self.make_context(client_config),
+      "continuation" => continuation,
+    }
+
+    return self._post_json("/youtubei/v1/next", data, client_config)
+  end
+
+  # :ditto:
+  def next(data : Hash, *, client_config : ClientConfig | Nil = nil)
+    # JSON Request data, required by the API
+    data2 = data.merge({
+      "context" => self.make_context(client_config),
+    })
+
+    return self._post_json("/youtubei/v1/next", data2, client_config)
+  end
+
+  # Allow a NamedTuple to be passed, too.
+  def next(data : NamedTuple, *, client_config : ClientConfig | Nil = nil)
+    return self.next(data.to_h, client_config: client_config)
+  end
+
+  ####################################################################
+  # player(video_id, params, client_config?)
+  #
+  # Requests the youtubei/v1/player endpoint with the required headers
+  # and POST data in order to get a JSON reply.
+  #
+  # The requested data is a video ID (`v=` parameter), with some
+  # additional paramters, formatted as a base64 string.
+  #
+  # An optional ClientConfig parameter can be passed, too (see
+  # `struct ClientConfig` above for more details).
+  #
+  def player(
+    video_id : String,
+    *, # Force the following paramters to be passed by name
+    params : String,
+    client_config : ClientConfig | Nil = nil
+  )
+    # JSON Request data, required by the API
+    data = {
+      "videoId" => video_id,
+      "context" => self.make_context(client_config),
+    }
+
+    # Append the additionnal parameters if those were provided
+    if params != ""
+      data["params"] = params
+    end
+
+    return self._post_json("/youtubei/v1/player", data, client_config)
+  end
+
+  ####################################################################
+  # resolve_url(url)
+  #
+  # Requests the youtubei/v1/navigation/resolve_url endpoint with the
+  # required headers and POST data in order to get a JSON reply.
+  #
+  # Output:
+  #
+  # ```
+  # # Valid channel "brand URL" gives the related UCID and browse ID
+  # channel_a = YoutubeAPI.resolve_url("https://youtube.com/c/google")
+  # channel_a # => {
+  #   "endpoint": {
+  #     "browseEndpoint": {
+  #       "params": "EgC4AQA%3D",
+  #       "browseId":"UCK8sQmJBp8GCxrOtXWBpyEA"
+  #     },
+  #     ...
+  #   }
+  # }
+  #
+  # # Invalid URL returns throws an InfoException
+  # channel_b = YoutubeAPI.resolve_url("https://youtube.com/c/invalid")
+  # ```
+  #
+  def resolve_url(url : String)
+    data = {
+      "context" => self.make_context(nil),
+      "url"     => url,
+    }
+
+    return self._post_json("/youtubei/v1/navigation/resolve_url", data)
+  end
+
+  ####################################################################
+  # search(search_query, params, client_config?)
   #
   # Requests the youtubei/v1/search endpoint with the required headers
   # and POST data in order to get a JSON reply. As the search results
@@ -78,19 +369,26 @@ end
   # The requested data is a search string, with some additional
   # paramters, formatted as a base64 string.
   #
-def request_youtube_api_search(search_query : String, params : String, region = nil)
+  # An optional ClientConfig parameter can be passed, too (see
+  # `struct ClientConfig` above for more details).
+  #
+  def search(
+    search_query : String,
+    params : String,
+    client_config : ClientConfig | Nil = nil
+  )
     # JSON Request data, required by the API
     data = {
       "query"   => search_query,
-    "context" => make_youtube_api_context(region),
+      "context" => self.make_context(client_config),
       "params"  => params,
     }
 
-  return _youtube_api_post_json("/youtubei/v1/search", data)
+    return self._post_json("/youtubei/v1/search", data, client_config)
   end
 
   ####################################################################
-# _youtube_api_post_json(endpoint, data)
+  # _post_json(endpoint, data, client_config?)
   #
   # Internal function that does the actual request to youtube servers
   # and handles errors.
@@ -98,14 +396,40 @@ end
   # The requested data is an endpoint (URL without the domain part)
   # and the data as a Hash object.
   #
-def _youtube_api_post_json(endpoint, data)
-  # Send the POST request and parse result
-  response = YT_POOL.client &.post(
-    "#{endpoint}?key=#{HARDCODED_API_KEY}",
-    headers: HTTP::Headers{"content-type" => "application/json; charset=UTF-8"},
-    body: data.to_json
-  )
+  def _post_json(
+    endpoint : String,
+    data : Hash,
+    client_config : ClientConfig | Nil
+  ) : Hash(String, JSON::Any)
+    # Use the default client config if nil is passed
+    client_config ||= DEFAULT_CLIENT_CONFIG
 
+    # Query parameters
+    url = "#{endpoint}?key=#{client_config.api_key}"
+
+    headers = HTTP::Headers{
+      "Content-Type"    => "application/json; charset=UTF-8",
+      "Accept-Encoding" => "gzip",
+    }
+
+    # Logging
+    LOGGER.debug("YoutubeAPI: Using endpoint: \"#{endpoint}\"")
+    LOGGER.trace("YoutubeAPI: ClientConfig: #{client_config.to_s}")
+    LOGGER.trace("YoutubeAPI: POST data: #{data.to_s}")
+
+    # Send the POST request
+    if client_config.proxy_region
+      response = YT_POOL.client(
+        client_config.proxy_region,
+        &.post(url, headers: headers, body: data.to_json)
+      )
+    else
+      response = YT_POOL.client &.post(
+        url, headers: headers, body: data.to_json
+      )
+    end
+
+    # Convert result to Hash
     initial_data = JSON.parse(response.body).as_h
 
     # Error handling
@@ -113,9 +437,15 @@ def _youtube_api_post_json(endpoint, data)
       code = initial_data["error"]["code"]
       message = initial_data["error"]["message"].to_s.sub(/(\\n)+\^$/, "")
 
+      # Logging
+      LOGGER.error("YoutubeAPI: Got error #{code} when requesting #{endpoint}")
+      LOGGER.error("YoutubeAPI: #{message}")
+      LOGGER.info("YoutubeAPI: POST data was: #{data.to_s}")
+
       raise InfoException.new("Could not extract JSON. Youtube API returned \
       error #{code} with message:<br>\"#{message}\"")
     end
 
     return initial_data
   end
+end # End of module

src/invidious/playlists.cr

@@ -361,7 +361,7 @@ def fetch_playlist(plid, locale)
     plid = "UU#{plid.lchop("UC")}"
   end
 
-  initial_data = request_youtube_api_browse("VL" + plid, params: "")
+  initial_data = YoutubeAPI.browse("VL" + plid, params: "")
 
   playlist_sidebar_renderer = initial_data["sidebar"]?.try &.["playlistSidebarRenderer"]?.try &.["items"]?
   raise InfoException.new("Could not extract playlistSidebarRenderer.") if !playlist_sidebar_renderer
@@ -442,9 +442,9 @@ def get_playlist_videos(db, playlist, offset, locale = nil, continuation = nil)
       offset = (offset / 100).to_i64 * 100_i64
 
       ctoken = produce_playlist_continuation(playlist.id, offset)
-      initial_data = request_youtube_api_browse(ctoken)
+      initial_data = YoutubeAPI.browse(ctoken)
     else
-      initial_data = request_youtube_api_browse("VL" + playlist.id, params: "")
+      initial_data = YoutubeAPI.browse("VL" + playlist.id, params: "")
     end
 
     return extract_playlist_videos(initial_data)

src/invidious/search.cr

@@ -244,7 +244,7 @@ def channel_search(query, page, channel)
   end
 
   continuation = produce_channel_search_continuation(ucid, query, page)
-  response_json = request_youtube_api_browse(continuation)
+  response_json = YoutubeAPI.browse(continuation)
 
   continuationItems = response_json["onResponseReceivedActions"]?
     .try &.[0]["appendContinuationItemsAction"]["continuationItems"]
@@ -263,7 +263,8 @@ end
 def search(query, search_params = produce_search_params(content_type: "all"), region = nil)
   return 0, [] of SearchItem if query.empty?
 
-  initial_data = request_youtube_api_search(query, search_params, region)
+  client_config = YoutubeAPI::ClientConfig.new(region: region)
+  initial_data = YoutubeAPI.search(query, search_params, client_config: client_config)
   items = extract_items(initial_data)
 
   return items.size, items

src/invidious/trending.cr

@@ -14,7 +14,8 @@ def fetch_trending(trending_type, region, locale)
     params = ""
   end
 
-  initial_data = request_youtube_api_browse("FEtrending", params: params, region: region)
+  client_config = YoutubeAPI::ClientConfig.new(region: region)
+  initial_data = YoutubeAPI.browse("FEtrending", params: params, client_config: client_config)
   trending = extract_videos(initial_data)
 
   return {trending, plid}