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Breaking changes in 2.2.0

SocketIOClient v2.2.0 makes System.Text.Json the default JSON serializer. If you'd like to continue to use Newtonsoft.Json, add the SocketIOClient.Newtonsoft.Json NuGet package and set your JsonSerializer to NewtonsoftJsonSerializer on your SocketIO instance. System.Text.Json is faster and uses less memory.

Simple example

• If the server uses socket.io v3, please set EIO explicitly

var client = new SocketIO("http://localhost:11000/", new SocketIOOptions
{
    EIO = 4
});

Emit an event

Client:

var client = new SocketIO("http://localhost:11000/");
client.On("hi", response =>
{
    string text = response.GetValue<string>();
});
client.OnConnected += async (sender, e) =>
{
    await client.EmitAsync("hi", ".net core");
};
await client.ConnectAsync();

Server:

socket.on("hi", name => {
    socket.emit("hi", `hi ${name}, You are connected to the server`);
});

Emit with Ack

Client:

var client = new SocketIO("http://localhost:11000/");
client.OnConnected += async (sender, e) =>
{
    await client.EmitAsync("ack", response =>
    {
        result = response.GetValue();
    }, ".net core");
};
await client.ConnectAsync();

Server:

socket.on("ack", (name, fn) => {
    fn({
        result: true,
        message: `ack(${name})`
    });
});

Emit with Binary

Client:

var client = new SocketIO("http://localhost:11000/");
client.OnConnected += async (sender, e) =>
{
    await client.EmitAsync("bytes", name, new
    {
        source = "client001",
        bytes = Encoding.UTF8.GetBytes(".net core")
    });
};

client.On("bytes", response =>
{
    var result = response.GetValue<ByteResponse>();
});

await client.ConnectAsync();

class ByteResponse
{
    public string ClientSource { get; set; }

    public string Source { get; set; }

    [JsonProperty("bytes")]
    public byte[] Buffer { get; set; }
}

Server:

socket.on("bytes", (name, data) => {
    const bytes = Buffer.from(data.bytes.toString() + " - server - " + name, "utf-8");
    socket.emit("bytes", {
        clientSource: data.source,
        source: "server",
        bytes
    });
});

Get multiple response values

Client:

var client = new SocketIO("http://localhost:11000/");
client.OnConnected += async (sender, e) =>
{
    await client.EmitAsync("change", new
    {
        code = 200,
        message = "val1"
    }, "val2");
};
client.On("change", response =>
{
    // You can get the JSON string of the response by calling response.ToString()
    // After that you can decide how to parse the response data.
    // For example: ["val2", { "code": 200, "message": "val1" }]
    string resVal1 = response.GetValue<string>();
    ChangeResponse resVal2 = response.GetValue<ChangeResponse>(1);

    // If you don't want to create a model, you can parse it like this
    var obj = response.GetValue(1);
    string message = obj.GetProperty("message").GetString();
    int code = obj.GetProperty("code").GetInt32();
});
await client.ConnectAsync();

class ChangeResponse
{
    public int Code { get; set; }
    public string Message { get; set; }
}

Server:

socket.on("change", (val1, val2) => {
    socket.emit("change", val2, val1);
})

SSL & Proxy

var proxy = new System.Net.WebProxy("http://example.com");
proxy.Credentials = new NetworkCredential("username", "password");

var socket = client.Socket as ClientWebSocket;
socket.Config = options =>
{
    options.RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) =>
    {
        Console.WriteLine("SslPolicyErrors: " + sslPolicyErrors);
        if (sslPolicyErrors == System.Net.Security.SslPolicyErrors.None)
        {
            return true;
        }
        return true;
    };
	
    // Set Proxy
    options.Proxy = proxy;
};
await client.ConnectAsync();

Custom JsonSerializerOptions/System.Text.Json

class MyJsonSerializer : SystemTextJsonSerializer
{
    public MyJsonSerializer(int eio) : base(eio) {}

    public override JsonSerializerOptions CreateOptions()
    {
        var options = new JsonSerializerOption();
        options.PropertyNameCaseInsensitive = true;
        return options;
    }
}

// ...

var client = new SocketIO("http://localhost:11000/");
client.JsonSerializer = new MyJsonSerializer(client.Options.EIO);

Custom JsonSerializerSettings/Newtonsoft.Json

class MyJsonSerializer : NewtonsoftJsonSerializer
{
    public MyJsonSerializer(int eio) : base(eio) {}

    public override JsonSerializerSettings CreateOptions()
    {
        return new JsonSerializerSettings
        {
            ContractResolver = new global::Newtonsoft.Json.Serialization.DefaultContractResolver
            {
                NamingStrategy = new global::Newtonsoft.Json.Serialization.CamelCaseNamingStrategy()
            },
            Formatting = Formatting.Indented
        };
    }
}

// ...

var client = new SocketIO("http://localhost:11000/");
client.JsonSerializer = new MyJsonSerializer(client.Options.EIO);

Windows 7

SocketIOClient does not support Windows 7. If your program will run on Windows 7, please uninstall SocketIOClient and install SocketIOClient.Windows7 from NuGet