Support OAuth2 Account Integration (#33)

* OAuth2 integration part 1

* implement token refreshing

* cleanups, usability, etc.

* Update log message, use Android.BASE_CONFIG for visitor ID fetching

* Reapply context filter.

* Don't apply token/UA/visitor ID to googlevideo URLs

* Allow skipping OAuth initialisation on empty tokens

* Fix incorrect number of arguments in YoutubeRestHandler

* Correctly extract interval, handle slow_down and access_denied

* Note usage of #getContextFilter with rotator.

* Slight refactor to oauth token handling and refreshing.

* README updates

* rename oauthConfig -> oauth

* Some minor changes.

* Remove todo and clear access token when setting new refresh token

README.md

@@ -14,6 +14,8 @@ Which clients are used is entirely configurable.
   - Information about the `plugin` module and usage of.
 - [Available Clients](#available-clients)
   - Information about the clients provided by `youtube-source`, as well as their advantages/disadvantages.
+- [Using OAuth tokens](#using-oauth-tokens)
+  - Information on using OAuth tokens with `youtube-source`.
 - [Using a poToken](#using-a-potoken)
   - Information on using a `poToken` with `youtube-source`.
 - [Migration Information](#migration-from-lavaplayers-built-in-youtube-source)
@@ -58,8 +60,9 @@ Support for IP rotation has been included, and can be achieved using the followi
 AbstractRoutePlanner routePlanner = new ...
 YoutubeIpRotatorSetup rotator = new YoutubeIpRotatorSetup(routePlanner);
 
+// 'youtube' is the variable holding your YoutubeAudioSourceManager instance.
 rotator.forConfiguration(youtube.getHttpInterfaceManager(), false)
-    .withMainDelegateFilter(null) // This is important, otherwise you may get NullPointerExceptions.
+    .withMainDelegateFilter(youtube.getContextFilter()) // IMPORTANT
     .setup();
 ```
 
@@ -206,6 +209,52 @@ Currently, the following clients are available for use:
   - ✔ Age-restricted video playback.
   - ❌ No playlist support.
 
+## Using OAuth Tokens
+You may notice that some requests are flagged by YouTube, causing an error message asking you to sign in to confirm you're not a bot.
+With OAuth integration, you can request that `youtube-source` use your account credentials to appear as a normal user, with varying degrees
+of efficacy. You can instruct `youtube-source` to use OAuth with the following:
+
+> [!WARNING]
+> Similar to the `poToken` method, this is NOT a silver bullet solution, and worst case could get your account terminated!
+> For this reason, it is advised that **you use burner accounts and NOT your primary!**.
+> This method may also trigger ratelimit errors if used in a high traffic environment.
+> USE WITH CAUTION!
+
+### Lavaplayer
+```java
+YoutubeAudioSourceManager source = new YoutubeAudioSourceManager();
+// This will trigger an OAuth flow, where you will be instructed to head to YouTube's OAuth page and input a code.
+// This is safe, as it only uses YouTube's official OAuth flow. No tokens are seen or stored by us.
+source.useOauth2(null, false);
+
+// If you already have a refresh token, you can instruct the source to use it, skipping the OAuth flow entirely.
+// You can also set the `skipInitialization` parameter, which skips the OAuth flow. This should only be used
+// if you intend to supply a refresh token later on. You **must** either complete the OAuth flow or supply
+// a refresh token for OAuth integration to work.
+source.useOauth2("your refresh token", true);
+```
+
+<!-- TODO document rest routes -->
+
+### Lavalink
+```yaml
+plugins:
+  youtube:
+    enabled: true
+    oauth:
+      # setting "enabled: true" is the bare minimum to get OAuth working.
+      enabled: true
+
+      # you may optionally set your refresh token if you have one, which skips the OAuth flow entirely.
+      # once you have completed the oauth flow at least once, you should see your refresh token within your
+      # lavalink logs, which can be used here.
+      refreshToken: "your refresh token, only supply this if you have one!"
+
+      # Set this if you don't want the OAuth flow to be triggered, if you intend to supply a refresh token
+      # later on via REST routes. Initialization is skipped automatically if a valid refresh token is supplied.
+      skipInitialization: true
+```
+
 ## Using a `poToken`
 A `poToken`, also known as a "Proof of Origin Token" is a way to identify what requests originate from.
 In YouTube's case, this is sent as a JavaScript challenge that browsers must evaluate, and send back the resolved

common/src/main/java/dev/lavalink/youtube/YoutubeAudioSourceManager.java

@@ -18,6 +18,7 @@
 import dev.lavalink.youtube.clients.skeleton.Client;
 import dev.lavalink.youtube.http.YoutubeAccessTokenTracker;
 import dev.lavalink.youtube.http.YoutubeHttpContextFilter;
+import dev.lavalink.youtube.http.YoutubeOauth2Handler;
 import dev.lavalink.youtube.track.YoutubeAudioTrack;
 import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpGet;
@@ -58,12 +59,15 @@ public class YoutubeAudioSourceManager implements AudioSourceManager {
     private static final Pattern shortHandPattern = Pattern.compile("^" + PROTOCOL_REGEX + "(?:" + DOMAIN_REGEX + "/(?:live|embed|shorts)|" + SHORT_DOMAIN_REGEX + ")/(?<videoId>.*)");
 
     protected final HttpInterfaceManager httpInterfaceManager;
+
     protected final boolean allowSearch;
     protected final boolean allowDirectVideoIds;
     protected final boolean allowDirectPlaylistIds;
     protected final Client[] clients;
 
-    protected final SignatureCipherManager cipherManager;
+    protected YoutubeHttpContextFilter contextFilter;
+    protected YoutubeOauth2Handler oauth2Handler;
+    protected SignatureCipherManager cipherManager;
 
     public YoutubeAudioSourceManager() {
         this(true);
@@ -133,11 +137,13 @@ public YoutubeAudioSourceManager(YoutubeSourceOptions options,
         this.allowDirectPlaylistIds = options.isAllowDirectPlaylistIds();
         this.clients = clients;
         this.cipherManager = new SignatureCipherManager();
+        this.oauth2Handler = new YoutubeOauth2Handler(httpInterfaceManager);
+
+        contextFilter = new YoutubeHttpContextFilter();
+        contextFilter.setTokenTracker(new YoutubeAccessTokenTracker(httpInterfaceManager));
+        contextFilter.setOauth2Handler(oauth2Handler);
 
-        YoutubeAccessTokenTracker tokenTracker = new YoutubeAccessTokenTracker(httpInterfaceManager);
-        YoutubeHttpContextFilter youtubeHttpContextFilter = new YoutubeHttpContextFilter();
-        youtubeHttpContextFilter.setTokenTracker(tokenTracker);
-        httpInterfaceManager.setHttpContextFilter(youtubeHttpContextFilter);
+        httpInterfaceManager.setHttpContextFilter(contextFilter);
     }
 
     @Override
@@ -151,6 +157,25 @@ public void setPlaylistPageCount(int count) {
         }
     }
 
+    /**
+     * Instructs this source to use Oauth2 integration.
+     * {@code null} is valid and will kickstart the oauth process.
+     * Providing a refresh token will likely skip having to authenticate your account prior to making requests,
+     * as long as the provided token is still valid.
+     * @param refreshToken The token to use for generating access tokens. Can be null.
+     * @param skipInitialization Whether linking of an account should be skipped, if you intend to provide a
+     *                           refresh token later. This only applies on null/empty/invalid refresh tokens.
+     *                           Valid refresh tokens will not be presented with an initialization prompt.
+     */
+    public void useOauth2(@Nullable String refreshToken, boolean skipInitialization) {
+        oauth2Handler.setRefreshToken(refreshToken, skipInitialization);
+    }
+
+    @Nullable
+    public String getOauth2RefreshToken() {
+        return oauth2Handler.getRefreshToken();
+    }
+
     @Override
     @Nullable
     public AudioItem loadItem(@NotNull AudioPlayerManager manager, @NotNull AudioReference reference) {
@@ -348,6 +373,16 @@ public Client[] getClients() {
         return clients;
     }
 
+    @NotNull
+    public YoutubeHttpContextFilter getContextFilter() {
+        return contextFilter;
+    }
+
+    @NotNull
+    public YoutubeOauth2Handler getOauth2Handler() {
+        return oauth2Handler;
+    }
+
     @NotNull
     public HttpInterfaceManager getHttpInterfaceManager() {
         return httpInterfaceManager;

common/src/main/java/dev/lavalink/youtube/http/YoutubeAccessTokenTracker.java

@@ -4,6 +4,7 @@
 import com.sedmelluq.discord.lavaplayer.tools.io.HttpClientTools;
 import com.sedmelluq.discord.lavaplayer.tools.io.HttpInterface;
 import com.sedmelluq.discord.lavaplayer.tools.io.HttpInterfaceManager;
+import dev.lavalink.youtube.clients.Android;
 import dev.lavalink.youtube.clients.ClientConfig;
 import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpPost;
@@ -69,16 +70,10 @@ private String fetchVisitorId() throws IOException {
     try (HttpInterface httpInterface = httpInterfaceManager.getInterface()) {
       httpInterface.getContext().setAttribute(TOKEN_FETCH_CONTEXT_ATTRIBUTE, true);
 
-      ClientConfig clientConfig = new ClientConfig()
-          .withUserAgent("com.google.android.youtube/19.07.39 (Linux; U; Android 11) gzip")
-          .withClientName("ANDROID")
-          .withClientField("clientVersion", "19.07.39")
-          .withClientField("androidSdkVersion", 30)
-          .withUserField("lockedSafetyMode", false)
-          .setAttributes(httpInterface);
+      ClientConfig client = Android.BASE_CONFIG.setAttributes(httpInterface);
 
       HttpPost visitorIdPost = new HttpPost("https://youtubei.googleapis.com/youtubei/v1/visitor_id");
-      visitorIdPost.setEntity(new StringEntity(clientConfig.toJsonString(), "UTF-8"));
+      visitorIdPost.setEntity(new StringEntity(client.toJsonString(), "UTF-8"));
 
       try (CloseableHttpResponse response = httpInterface.execute(visitorIdPost)) {
         HttpClientTools.assertSuccessWithContent(response, "youtube visitor id");

common/src/main/java/dev/lavalink/youtube/http/YoutubeHttpContextFilter.java

@@ -24,11 +24,16 @@ public class YoutubeHttpContextFilter extends BaseYoutubeHttpContextFilter {
   private static final HttpContextRetryCounter retryCounter = new HttpContextRetryCounter("yt-token-retry");
 
   private YoutubeAccessTokenTracker tokenTracker;
+  private YoutubeOauth2Handler oauth2Handler;
 
   public void setTokenTracker(@NotNull YoutubeAccessTokenTracker tokenTracker) {
     this.tokenTracker = tokenTracker;
   }
 
+  public void setOauth2Handler(@NotNull YoutubeOauth2Handler oauth2Handler) {
+    this.oauth2Handler = oauth2Handler;
+  }
+
   @Override
   public void onContextOpen(HttpClientContext context) {
     CookieStore cookieStore = context.getCookieStore();
@@ -57,16 +62,24 @@ public void onRequest(HttpClientContext context,
       return;
     }
 
+    if (oauth2Handler.isOauthFetchContext(context)) {
+      return;
+    }
+
     String userAgent = context.getAttribute(ATTRIBUTE_USER_AGENT_SPECIFIED, String.class);
 
-    if (userAgent != null) {
-      request.setHeader("User-Agent", userAgent);
+    if (!request.getURI().getHost().contains("googlevideo")) {
+      if (userAgent != null) {
+        request.setHeader("User-Agent", userAgent);
+
+        String visitorData = context.getAttribute(ATTRIBUTE_VISITOR_DATA_SPECIFIED, String.class);
+        request.setHeader("X-Goog-Visitor-Id", visitorData != null ? visitorData : tokenTracker.getVisitorId());
 
-      String visitorData = context.getAttribute(ATTRIBUTE_VISITOR_DATA_SPECIFIED, String.class);
-      request.setHeader("X-Goog-Visitor-Id", visitorData != null ? visitorData : tokenTracker.getVisitorId());
+        context.removeAttribute(ATTRIBUTE_VISITOR_DATA_SPECIFIED);
+        context.removeAttribute(ATTRIBUTE_USER_AGENT_SPECIFIED);
+      }
 
-      context.removeAttribute(ATTRIBUTE_VISITOR_DATA_SPECIFIED);
-      context.removeAttribute(ATTRIBUTE_USER_AGENT_SPECIFIED);
+      oauth2Handler.applyToken(request);
     }
 
 //    try {