From 5690324f2752ce5da8881bf0f88dc387a389db7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alessandro=20Calabr=C3=B2?=
 <153992315+Ales315@users.noreply.github.com>
Date: Sat, 25 Jan 2025 22:02:46 +0100
Subject: [PATCH] Update iOS client and add random visitor data to requests
 (#865)

---
 YoutubeExplode/Utils/ProtoBuilder.cs         | 81 ++++++++++++++++++++
 YoutubeExplode/Utils/YoutubeParsingHelper.cs | 45 +++++++++++
 YoutubeExplode/Videos/VideoController.cs     | 17 ++--
 3 files changed, 137 insertions(+), 6 deletions(-)
 create mode 100644 YoutubeExplode/Utils/ProtoBuilder.cs
 create mode 100644 YoutubeExplode/Utils/YoutubeParsingHelper.cs

diff --git a/YoutubeExplode/Utils/ProtoBuilder.cs b/YoutubeExplode/Utils/ProtoBuilder.cs
new file mode 100644
index 00000000..1661ed6b
--- /dev/null
+++ b/YoutubeExplode/Utils/ProtoBuilder.cs
@@ -0,0 +1,81 @@
+using System;
+using System.IO;
+using System.Text;
+
+namespace YoutubeExplode.Utils
+{
+    internal class ProtoBuilder
+    {
+        private MemoryStream _byteBuffer;
+
+        public ProtoBuilder()
+        {
+            _byteBuffer = new MemoryStream();
+        }
+
+        public byte[] ToBytes()
+        {
+            return _byteBuffer.ToArray();
+        }
+
+        public string ToUrlencodedBase64()
+        {
+            var b64 = Convert
+                .ToBase64String(ToBytes())
+                .Replace('+', '-')
+                .Replace('/', '_')
+                .TrimEnd('=');
+            return Uri.EscapeDataString(b64);
+        }
+
+        private void WriteVarint(long val)
+        {
+            if (val == 0)
+            {
+                _byteBuffer.WriteByte(0);
+            }
+            else
+            {
+                long v = val;
+                while (v != 0)
+                {
+                    byte b = (byte)(v & 0x7F);
+                    v >>= 7;
+
+                    if (v != 0)
+                    {
+                        b |= 0x80;
+                    }
+                    _byteBuffer.WriteByte(b);
+                }
+            }
+        }
+
+        private void Field(int field, byte wire)
+        {
+            long fbits = ((long)field) << 3;
+            long wbits = ((long)wire) & 0x07;
+            long val = fbits | wbits;
+            WriteVarint(val);
+        }
+
+        public void Varint(int field, long val)
+        {
+            Field(field, 0);
+            WriteVarint(val);
+        }
+
+        public void String(int field, string str)
+        {
+            var strBytes = Encoding.UTF8.GetBytes(str);
+            Bytes(field, strBytes);
+        }
+
+        public void Bytes(int field, byte[] bytes)
+        {
+            Field(field, 2);
+            WriteVarint(bytes.Length);
+            _byteBuffer.Write(bytes, 0, bytes.Length);
+        }
+    }
+}
diff --git a/YoutubeExplode/Utils/YoutubeParsingHelper.cs b/YoutubeExplode/Utils/YoutubeParsingHelper.cs
new file mode 100644
index 00000000..eb78b41a
--- /dev/null
+++ b/YoutubeExplode/Utils/YoutubeParsingHelper.cs
@@ -0,0 +1,45 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+
+namespace YoutubeExplode.Utils
+{
+    internal static class YoutubeParsingHelper
+    {
+        private static string CONTENT_PLAYBACK_NONCE_ALPHABET =
+            "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+
+        public static string GetRandomVisitorData()
+        {
+            Random r = new Random();
+            ProtoBuilder pbE2 = new ProtoBuilder();
+            pbE2.String(2, "");
+            pbE2.Varint(4, r.Next(255) + 1);
+
+            ProtoBuilder pbE = new ProtoBuilder();
+            pbE.String(1, "US");
+            pbE.Bytes(2, pbE2.ToBytes());
+
+            ProtoBuilder pb = new ProtoBuilder();
+            pb.String(1, GenerateRandomStringFromAlphabet(CONTENT_PLAYBACK_NONCE_ALPHABET, 11, r));
+            pb.Varint(5, DateTimeOffset.UtcNow.ToUnixTimeMilliseconds() / 1000 - r.Next(600000));
+            pb.Bytes(6, pbE.ToBytes());
+            return pb.ToUrlencodedBase64();
+        }
+
+        private static string GenerateRandomStringFromAlphabet(
+            string alphabet,
+            int length,
+            Random random
+        )
+        {
+            StringBuilder sb = new StringBuilder();
+            for (int i = 0; i < length; i++)
+            {
+                sb.Append(alphabet.ElementAt(random.Next(alphabet.Length)));
+            }
+            return sb.ToString();
+        }
+    }
+}
diff --git a/YoutubeExplode/Videos/VideoController.cs b/YoutubeExplode/Videos/VideoController.cs
index 2f2c3de2..52173be1 100644
--- a/YoutubeExplode/Videos/VideoController.cs
+++ b/YoutubeExplode/Videos/VideoController.cs
@@ -11,6 +11,8 @@ internal class VideoController(HttpClient http)
 {
     protected HttpClient Http { get; } = http;
 
+    private string _visitorData = null!;
+
     public async ValueTask<VideoWatchPage> GetVideoWatchPageAsync(
         VideoId videoId,
         CancellationToken cancellationToken = default
@@ -61,6 +63,9 @@ public async ValueTask<PlayerResponse> GetPlayerResponseAsync(
             "https://www.youtube.com/youtubei/v1/player"
         );
 
+        if (_visitorData == null)
+            _visitorData = YoutubeParsingHelper.GetRandomVisitorData();
+
         request.Content = new StringContent(
             // lang=json
             $$"""
@@ -70,14 +75,14 @@ public async ValueTask<PlayerResponse> GetPlayerResponseAsync(
               "context": {
                 "client": {
                   "clientName": "IOS",
-                  "clientVersion": "19.29.1",
+                  "clientVersion": "19.45.4",
                   "deviceMake": "Apple",
                   "deviceModel": "iPhone16,2",
+                  "platform": "MOBILE",
+                  "osName": "IOS",
+                  "osVersion": "18.1.0.22B83",
+                  "visitorData": {{Json.Serialize(_visitorData)}},
                   "hl": "en",
-                  "osName": "iPhone",
-                  "osVersion": "17.5.1.21F90",
-                  "timeZone": "UTC",
-                  "userAgent": "com.google.ios.youtube/19.29.1 (iPhone16,2; U; CPU iOS 17_5_1 like Mac OS X;)",
                   "gl": "US",
                   "utcOffsetMinutes": 0
                 }
@@ -90,7 +95,7 @@ public async ValueTask<PlayerResponse> GetPlayerResponseAsync(
         // https://github.com/iv-org/invidious/issues/3230#issuecomment-1226887639
         request.Headers.Add(
             "User-Agent",
-            "com.google.ios.youtube/19.29.1 (iPhone16,2; U; CPU iOS 17_5_1 like Mac OS X)"
+            "com.google.ios.youtube/19.45.4 (iPhone16,2; U; CPU iOS 18_1_0 like Mac OS X; US)"
         );
 
         using var response = await Http.SendAsync(request, cancellationToken);