SocketIOOptions missing Transport/RemoteCertificateValidationCallback in Unity (SSL bypass needed)

[LucaFilippetti99]

SocketIOClient 3.1.2 in Unity fails to compile with SSL bypass for WSS (Tailscale self-signed cert).

• SocketIOClient: 3.1.2
• Unity 6.3 LTS (Android/XR target)
• Server: Socket.IO wss:// with self-signed cert

Current workarounds fail:
1.ServicePointManager.ServerCertificateValidationCallback → Doesn't work for WSS upgrade
2.HTTPS works fine with Unity BypassCertificateHandler

Question: What are the exact SocketIOOptions properties available in 3.1.2 for Unity WSS + SSL bypass?

This is my snippet code with the options of the socket:
"
var options = new SocketIOOptions
{
ConnectionTimeout = TimeSpan.FromSeconds(APIStrings.webSocketTimeoutSeconds),
Transport = SocketIOClient.Transport.TransportProtocol.WebSocket,
Reconnection = true,
ReconnectionAttempts = 10,
ReconnectionDelay = 1000,
RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true
};

        _socket = new SocketIOClient.SocketIO(https://100.82.42.53:5090, options);

"

I have also tried "wss://100.82.42.53:5090" instead of "https://100.82.42.53:5090" but nothing work

[LucaFilippetti99]

To resolve the SSL bypass limitations of v3, I have completely migrated the project to SocketIOClient v4. I am attempting to use the new Dependency Injection (DI) architecture to bypass the self-signed certificate validation for both the initial HTTP handshake and the WebSocket transport.

Current Setup:

Library: SocketIOClient v4.x

Environment: Unity 6.3 LTS (IL2CPP backend, Android/XR target)

Server: https://.... (Self-signed certificate)

What I have tried in v4:
I followed the integration tests approach. I injected a custom HttpClient (for the Engine.IO polling/handshake) and WebSocketOptions (for the WSS stream), forcing the RemoteCertificateValidationCallback to always return true. I also set TransportProtocol.WebSocket to skip polling overhead.

Here is my exact initialization code:

C#
var options = new SocketIOClient.SocketIOOptions
{
    EIO = EngineIO.V4,
    Transport = TransportProtocol.WebSocket, 
    ConnectionTimeout = TimeSpan.FromSeconds(30), 
    Reconnection = true, 
    ReconnectionAttempts = 10
};

_socket = new SocketIOClient.SocketIO(new Uri("https://...."), options, services =>
{
    // 1. Bypass for potential HTTP handshake/fallback
    services.AddSingleton<HttpClient>(_ =>
    {
        var handler = new HttpClientHandler
        {
            ServerCertificateCustomValidationCallback = (sender, cert, chain, errs) => true
        };
        return new HttpClient(handler);
    });
    
    // 2. Bypass for WebSocket transport
    services.AddSingleton(new WebSocketOptions
    {
        RemoteCertificateValidationCallback = (sender, cert, chain, errs) => true
    });
});

await _socket.ConnectAsync();

The Symptom:
The connection still fails with a generic top-level exception: Connection failed: Cannot connect to server 'https://..../'.
Meanwhile, standard HTTP calls using Unity's native UnityWebRequest to the exact same HTTPS endpoint work flawlessly when using a custom CertificateHandler.

My Questions:

Is there a known limitation or a specific quirk with the .NET internal ClientWebSocket ignoring the DI-injected RemoteCertificateValidationCallback when running under Unity's IL2CPP runtime?

Is my DI configuration missing something required to truly force the library to ignore self-signed certificates in v4?

How can I extract a more verbose InnerException from the internal transport to pinpoint exactly where the handshake is dropping?

Any insights for Unity environments would be greatly appreciated!

[doghappy]

Hi @LucaFilippetti99

If you could provide a reproducible repo, that would be very helpful.

In the other hand, could you share the exception stack trace & more detailed logging? To enable more detailed logging, please refer to https://github.com/doghappy/socket.io-client-csharp#logging

for the SocketIOClient v4.x