feat(twitch): block-embedded-ads patch (#231)

Co-authored-by: Tim Schneeberger <tim.schneeberger@outlook.de>

app/build.gradle.kts

@@ -46,4 +46,6 @@ dependencies {
     compileOnly(project(mapOf("path" to ":dummy")))
     compileOnly("androidx.annotation:annotation:1.5.0")
     compileOnly("androidx.appcompat:appcompat:1.5.1")
+    compileOnly("com.squareup.okhttp3:okhttp:4.10.0")
+    compileOnly("com.squareup.retrofit2:retrofit:2.9.0")
 }

app/src/main/java/app/revanced/twitch/adblock/IAdblockService.kt

@@ -0,0 +1,18 @@
+package app.revanced.twitch.adblock
+
+import okhttp3.Request
+
+interface IAdblockService {
+    fun friendlyName(): String
+    fun maxAttempts(): Int
+    fun isAvailable(): Boolean
+    fun rewriteHlsRequest(originalRequest: Request): Request?
+
+    companion object {
+        fun Request.isVod() = url.pathSegments.contains("vod")
+        fun Request.channelName() =
+            url.pathSegments
+                .firstOrNull { it.endsWith(".m3u8") }
+                .run { this?.replace(".m3u8", "") }
+    }
+}

app/src/main/java/app/revanced/twitch/adblock/PurpleAdblockService.kt

@@ -0,0 +1,68 @@
+package app.revanced.twitch.adblock
+
+import app.revanced.twitch.adblock.IAdblockService.Companion.channelName
+import app.revanced.twitch.api.RetrofitClient
+import app.revanced.twitch.utils.LogHelper
+import app.revanced.twitch.utils.ReVancedUtils
+import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
+import okhttp3.Request
+import okhttp3.ResponseBody
+
+class PurpleAdblockService : IAdblockService {
+    private val tunnels = mutableMapOf(
+        /* tunnel url */        /* alive */
+        "https://eu1.jupter.ga" to false,
+        "https://eu2.jupter.ga" to false
+    )
+
+    override fun friendlyName(): String = ReVancedUtils.getString("revanced_proxy_purpleadblock")
+
+    override fun maxAttempts(): Int = 3
+
+    override fun isAvailable(): Boolean {
+        for(tunnel in tunnels.keys) {
+            var success = true
+            try {
+                val response = RetrofitClient.getInstance().purpleAdblockApi.ping(tunnel).execute()
+                if (!response.isSuccessful) {
+                    LogHelper.error("PurpleAdBlock tunnel $tunnel returned an error: HTTP code %d", response.code())
+                    LogHelper.debug(response.message())
+                    LogHelper.debug((response.errorBody() as ResponseBody).string())
+                    success = false
+                }
+            } catch (ex: Exception) {
+                LogHelper.printException("PurpleAdBlock tunnel $tunnel is unavailable", ex)
+                success = false
+            }
+
+            // Cache availability data
+            tunnels[tunnel] = success
+
+            if(success)
+                return true
+        }
+
+        return false
+    }
+
+    override fun rewriteHlsRequest(originalRequest: Request): Request? {
+        val server = tunnels.filter { it.value }.map { it.key }.firstOrNull()
+        server ?: run {
+            LogHelper.error("No tunnels are available")
+            return null
+        }
+
+        // Compose new URL
+        val url = "$server/channel/${originalRequest.channelName()}".toHttpUrlOrNull()
+        if (url == null) {
+            LogHelper.error("Failed to parse rewritten URL")
+            return null
+        }
+
+        // Overwrite old request
+        return Request.Builder()
+            .get()
+            .url(url)
+            .build()
+    }
+}

app/src/main/java/app/revanced/twitch/adblock/TTVLolService.kt

@@ -0,0 +1,52 @@
+package app.revanced.twitch.adblock
+
+import app.revanced.twitch.adblock.IAdblockService.Companion.channelName
+import app.revanced.twitch.adblock.IAdblockService.Companion.isVod
+import app.revanced.twitch.utils.LogHelper
+import app.revanced.twitch.utils.ReVancedUtils
+import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
+import okhttp3.Request
+import java.util.Random
+
+class TTVLolService : IAdblockService {
+
+    override fun friendlyName(): String = ReVancedUtils.getString("revanced_proxy_ttv_lol")
+
+    // TTV.lol is sometimes unstable
+    override fun maxAttempts(): Int = 4
+
+    override fun isAvailable(): Boolean = true
+
+    override fun rewriteHlsRequest(originalRequest: Request): Request? {
+        // Compose new URL
+        val url = "https://api.ttv.lol/${if (originalRequest.isVod()) "vod" else "playlist"}/${originalRequest.channelName()}.m3u8${nextQuery()}".toHttpUrlOrNull()
+        if (url == null) {
+            LogHelper.error("Failed to parse rewritten URL")
+            return null
+        }
+
+        // Overwrite old request
+        return Request.Builder()
+            .get()
+            .url(url)
+            .addHeader("X-Donate-To", "https://ttv.lol/donate")
+            .build()
+    }
+
+    private fun nextQuery(): String {
+        return SAMPLE_QUERY.replace("<SESSION>", generateSessionId())
+    }
+
+    private fun generateSessionId() =
+        (1..32)
+            .map { "abcdef0123456789"[randomSource.nextInt(16)] }
+            .joinToString("")
+
+    private val randomSource = Random()
+
+    companion object {
+
+        private const val SAMPLE_QUERY =
+            "%3Fallow_source%3Dtrue%26fast_bread%3Dtrue%26allow_audio_only%3Dtrue%26p%3D0%26play_session_id%3D<SESSION>%26player_backend%3Dmediaplayer%26warp%3Dfalse%26force_preroll%3Dfalse%26mobile_cellular%3Dfalse"
+    }
+}

app/src/main/java/app/revanced/twitch/api/PurpleAdblockApi.java

@@ -0,0 +1,12 @@
+package app.revanced.twitch.api;
+
+import okhttp3.ResponseBody;
+import retrofit2.Call;
+import retrofit2.http.GET;
+import retrofit2.http.Url;
+
+/* only used for service pings */
+public interface PurpleAdblockApi {
+    @GET /* root */
+    Call<ResponseBody> ping(@Url String baseUrl);
+}

app/src/main/java/app/revanced/twitch/api/RequestInterceptor.kt

@@ -0,0 +1,86 @@
+package app.revanced.twitch.api
+
+import app.revanced.twitch.adblock.IAdblockService
+import app.revanced.twitch.adblock.IAdblockService.Companion.channelName
+import app.revanced.twitch.adblock.IAdblockService.Companion.isVod
+import app.revanced.twitch.adblock.PurpleAdblockService
+import app.revanced.twitch.adblock.TTVLolService
+import app.revanced.twitch.settings.SettingsEnum
+import app.revanced.twitch.utils.LogHelper
+import app.revanced.twitch.utils.ReVancedUtils
+import okhttp3.*
+
+class RequestInterceptor : Interceptor {
+    private var activeService: IAdblockService? = null
+
+    private fun updateActiveService() {
+        val current = SettingsEnum.BLOCK_EMBEDDED_ADS.string
+        activeService = if(current == ReVancedUtils.getString("key_revanced_proxy_ttv_lol") && activeService !is TTVLolService)
+            TTVLolService()
+        else if(current == ReVancedUtils.getString("key_revanced_proxy_purpleadblock") && activeService !is PurpleAdblockService)
+            PurpleAdblockService()
+        else if(current == ReVancedUtils.getString("key_revanced_proxy_disabled"))
+            null
+        else
+            activeService
+    }
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val originalRequest = chain.request()
+        LogHelper.debug("Intercepted request to URL: %s", originalRequest.url.toString())
+
+        // Skip if not HLS manifest request
+        if (!originalRequest.url.host.contains("usher.ttvnw.net")) {
+            return chain.proceed(originalRequest)
+        }
+
+        LogHelper.debug("Found HLS manifest request. Is VOD? %s; Channel: %s",
+            if (originalRequest.isVod()) "yes" else "no", originalRequest.channelName())
+
+        // None of the services support VODs currently
+        if(originalRequest.isVod())
+            return chain.proceed(originalRequest)
+
+        updateActiveService()
+
+        activeService?.let {
+            val available = it.isAvailable()
+            val rewritten = it.rewriteHlsRequest(originalRequest)
+
+            if (!available || rewritten == null) {
+                ReVancedUtils.toast(
+                    String.format(ReVancedUtils.getString("revanced_embedded_ads_service_unavailable"), it.friendlyName()),
+                    true
+                )
+                return chain.proceed(originalRequest)
+            }
+
+            LogHelper.debug("Rewritten HLS stream URL: %s", rewritten.url.toString())
+
+            val maxAttempts = it.maxAttempts()
+            for(i in 1..maxAttempts) {
+                // Execute rewritten request and close body to allow multiple proceed() calls
+                val response = chain.proceed(rewritten).apply { close() }
+                if(!response.isSuccessful) {
+                    LogHelper.error("Request failed (attempt %d/%d): HTTP error %d (%s)",
+                        i, maxAttempts, response.code, response.message)
+                    Thread.sleep(50)
+                }
+                else {
+                    // Accept response from ad blocker
+                    LogHelper.debug("Ad-blocker used")
+                    return chain.proceed(rewritten)
+                }
+            }
+
+            // maxAttempts exceeded; giving up on using the ad blocker
+            ReVancedUtils.toast(
+                String.format(ReVancedUtils.getString("revanced_embedded_ads_service_failed"), it.friendlyName()),
+                true
+            )
+        }
+
+        // Adblock disabled
+        return chain.proceed(originalRequest)
+    }
+}

app/src/main/java/app/revanced/twitch/api/RetrofitClient.java

@@ -0,0 +1,25 @@
+package app.revanced.twitch.api;
+
+import retrofit2.Retrofit;
+
+public class RetrofitClient {
+
+    private static RetrofitClient instance = null;
+    private final PurpleAdblockApi purpleAdblockApi;
+
+    private RetrofitClient() {
+        Retrofit retrofit = new Retrofit.Builder().baseUrl("http://localhost" /* dummy */).build();
+        purpleAdblockApi = retrofit.create(PurpleAdblockApi.class);
+    }
+
+    public static synchronized RetrofitClient getInstance() {
+        if (instance == null) {
+            instance = new RetrofitClient();
+        }
+        return instance;
+    }
+
+    public PurpleAdblockApi getPurpleAdblockApi() {
+        return purpleAdblockApi;
+    }
+}

app/src/main/java/app/revanced/twitch/patches/EmbeddedAdsPatch.java

@@ -0,0 +1,9 @@
+package app.revanced.twitch.patches;
+
+import app.revanced.twitch.api.RequestInterceptor;
+
+public class EmbeddedAdsPatch {
+    public static RequestInterceptor createRequestInterceptor() {
+        return new RequestInterceptor();
+    }
+}

app/src/main/java/app/revanced/twitch/settings/SettingsEnum.java

@@ -10,6 +10,7 @@ public enum SettingsEnum {
     /* Ads */
     BLOCK_VIDEO_ADS("revanced_block_video_ads", true, ReturnType.BOOLEAN),
     BLOCK_AUDIO_ADS("revanced_block_audio_ads", true, ReturnType.BOOLEAN),
+    BLOCK_EMBEDDED_ADS("revanced_block_embedded_ads", "ttv-lol", ReturnType.STRING),
 
     /* Chat */
     SHOW_DELETED_MESSAGES("revanced_show_deleted_messages", "cross-out", ReturnType.STRING),

app/src/main/java/app/revanced/twitch/utils/LogHelper.java

@@ -43,7 +43,7 @@ public static void printException(String message, Throwable ex) {
 
     private static void showDebugToast(String msg) {
         if(SettingsEnum.DEBUG_MODE.getBoolean()) {
-            ReVancedUtils.ifContextAttached((c) -> Toast.makeText(c, msg, Toast.LENGTH_SHORT).show());
+            ReVancedUtils.toast(msg, false);
         }
     }
 }

app/src/main/java/app/revanced/twitch/utils/ReVancedUtils.java

@@ -2,6 +2,9 @@
 
 import android.annotation.SuppressLint;
 import android.content.Context;
+import android.os.Handler;
+import android.os.Looper;
+import android.widget.Toast;
 
 public class ReVancedUtils {
     @SuppressLint("StaticFieldLeak")
@@ -53,6 +56,10 @@ public interface SafeContextAccessLambda {
         void run(Context ctx);
     }
 
+    public static void runOnMainThread(Runnable runnable) {
+        new Handler(Looper.getMainLooper()).post(runnable);
+    }
+
     /**
      * Get resource id safely
      * @return May return 0 if resource not found or context not attached
@@ -84,4 +91,13 @@ public static int getDrawableId(String name) {
     public static String getString(String name) {
         return ifContextAttached((c) -> c.getString(getStringId(name)), "");
     }
+
+    public static void toast(String message) {
+        toast(message, true);
+    }
+    public static void toast(String message, boolean longLength) {
+        ifContextAttached((c) -> {
+            runOnMainThread(() -> Toast.makeText(c, message, longLength ? Toast.LENGTH_LONG : Toast.LENGTH_SHORT).show());
+        });
+    }
 }