# EonaCat.Network

[![NuGet](https://img.shields.io/nuget/v/EonaCat.Network.svg)](https://www.nuget.org/packages/EonaCat.Network/)
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[![License](https://img.shields.io/badge/license-Apache%202.0-blue.svg)](LICENSE)

**EonaCat.Network** is a .NET networking library that provides a common set of APIs for building networked applications and services.

The library includes support for:

- TCP client and server communication
- UDP client and server communication
- WebSockets
- An embedded HTTP/HTTPS web server
- HTTP routing, including static and parameterized routes
- QUIC client/server and stream primitives
- IPv4 and IPv6 networking
- TCP SSL/TLS support
- WebSocket extensions, fragmentation and compression support
- Network-related helper and utility classes

## Installation

Install the NuGet package:

```bash
dotnet add package EonaCat.Network
```

NuGet:

https://www.nuget.org/packages/EonaCat.Network/

## Target Frameworks

The library currently targets:

- .NET Framework 4.8 (`net48`)
- .NET Standard 2.1
- .NET 6
- .NET 7
- .NET 8

## Quick Start

### TCP server

```csharp
using EonaCat.Network;
using System.Net;
using System.Threading;
using System.Threading.Tasks;

var server = new SocketTcpServer(IPAddress.Any, 5000);

server.OnConnect += remote =>
{
    Console.WriteLine("Client connected");
};

server.OnReceive += (remote, message) =>
{
    Console.WriteLine($"Received: {message}");
};

server.OnDisconnect += remote =>
{
    Console.WriteLine("Client disconnected");
};

server.OnError += (exception, message) =>
{
    Console.WriteLine(message);
};

await server.StartAsync(CancellationToken.None);
```

### TCP client

```csharp
using EonaCat.Network;

var client = new SocketTcpClient();

client.OnConnect += remote =>
{
    Console.WriteLine("Connected");
};

client.OnReceive += remote =>
{
    Console.WriteLine($"Received {remote.Data?.Length ?? 0} bytes");
};

client.OnDisconnect += remote =>
{
    Console.WriteLine("Disconnected");
};

client.OnError += (exception, message) =>
{
    Console.WriteLine(message);
};

await client.ConnectAsync("127.0.0.1", 5000);

await client.SendAsync(
    System.Text.Encoding.UTF8.GetBytes("Hello from EonaCat.Network!"));
```

### UDP server

```csharp
using EonaCat.Network;
using System.Net;

var server = new SocketUdpServer(IPAddress.Any, 5001);

server.OnReceive += remote =>
{
    Console.WriteLine($"Received {remote.Data?.Length ?? 0} bytes");
};

server.OnSend += remote =>
{
    Console.WriteLine("UDP packet sent");
};

server.OnError += (exception, message) =>
{
    Console.WriteLine(message);
};

await server.StartAsync();
```

Send a packet:

```csharp
await server.SendToAsync(
    new IPEndPoint(IPAddress.Loopback, 5002),
    System.Text.Encoding.UTF8.GetBytes("Hello UDP"));
```

### UDP client

```csharp
using EonaCat.Network;
using System.Net;

var client = new SocketUdpClient(IPAddress.Loopback, 5001);

client.OnReceive += data =>
{
    Console.WriteLine($"Received {data.Length} bytes");
};

client.OnError += (exception, message) =>
{
    Console.WriteLine(message);
};

await client.SendTo(
    new IPEndPoint(IPAddress.Loopback, 5001),
    System.Text.Encoding.UTF8.GetBytes("Hello UDP"));
```

## Embedded Web Server

The library includes an HTTP/HTTPS web server exposed through `WebServer` (`EonaCat.Network.WebServer`).

### Start a web server

```csharp
using EonaCat.Network;

var server = new WebServer("localhost", 8080);

await server.StartAsync();
```

For synchronous startup:

```csharp
server.Start();
```

Stop it with:

```csharp
server.Stop();
```

Or dispose it:

```csharp
server.Dispose();
```

### Web server settings

You can configure the server through `EonaCatWebserverSettings`:

```csharp
using EonaCat.Network;

var settings = new EonaCatWebserverSettings("localhost", 8080);

settings.IO.MaxRequests = 1024;
settings.IO.StreamBufferSize = 65536;

settings.Debug.Requests = true;
settings.Debug.Responses = true;
settings.Debug.Routing = true;

var server = new WebServer(settings);

await server.StartAsync();
```

The settings API includes:

- Listening prefixes
- I/O buffer size
- Maximum concurrent requests
- SSL settings
- Default response headers
- Access-control configuration
- Debug logging options

> **Security note:** review the SSL and access-control configuration before exposing a server to an untrusted network. The current settings class allows invalid certificates by default, so production deployments should explicitly configure certificate validation behavior appropriate to the application.

### Web server events

The server exposes events for common lifecycle and HTTP operations through `server.Events`, including:

- `ConnectionReceived`
- `RequestReceived`
- `RequestDenied`
- `RequestorDisconnected`
- `ResponseSent`
- `ExceptionEncountered`
- `ServerStarted`
- `ServerStopped`
- `ServerDisposing`

Example:

```csharp
server.Events.ServerStarted += (_, _) =>
{
    Console.WriteLine("Web server started");
};

server.Events.RequestReceived += (_, args) =>
{
    Console.WriteLine("HTTP request received");
};
```

## HTTP Routing

EonaCat.Network provides several route types.

### Static routes

`StaticRouteManager` matches an HTTP method and exact path.

```csharp
var routes = new StaticRouteManager();

routes.Add(
    HttpMethod.GET,
    "/hello",
    async context =>
    {
        // Build and send the response here.
        await Task.CompletedTask;
    });
```

Static routes normalize paths to begin and end with `/` and use case-insensitive matching.

Useful operations include:

```csharp
routes.Add(...);
routes.Get(HttpMethod.GET, "/hello");
routes.Exists(HttpMethod.GET, "/hello");
routes.Remove(HttpMethod.GET, "/hello");
```

### Parameter routes

`ParameterRouteManager` supports URL parameters such as:

```text
GET /api/{version}/users
```

Example:

```csharp
var routes = new ParameterRouteManager();

routes.Add(
    HttpMethod.GET,
    "/api/{version}/users",
    async context =>
    {
        await Task.CompletedTask;
    });
```

The matching operation returns the extracted values:

```csharp
Dictionary<string, string> values;
ParameterRoute route;

var handler = routes.Match(
    HttpMethod.GET,
    "/api/v1/users",
    out values,
    out route);
```

For the example above, `values` can contain:

```text
version = v1
```

## WebSockets

The library contains asynchronous WebSocket client and server implementations under the `EonaCat.WebSockets` namespace.

Supported functionality includes:

- Text messages
- Binary messages
- Streaming binary data
- Sessions
- Broadcasting
- Fragmentation
- Close handling
- Sub-protocol support
- WebSocket extensions
- Per-message compression support

### WebSocket client

```csharp
using EonaCat.WebSockets;

var client = new AsyncWebSocketClient(
    new Uri("ws://localhost:8080/"));

await client.ConnectAsync();

await client.SendTextAsync("Hello WebSocket!");
```

Binary data:

```csharp
await client.SendBinaryAsync(
    System.Text.Encoding.UTF8.GetBytes("Binary message"));
```

Close the connection:

```csharp
await client.CloseAsync();
```

### WebSocket server

The server uses `AsyncWebSocketServerModule` implementations to handle sessions and messages.

A module can override handlers such as:

```csharp
public override async Task OnSessionStarted(
    AsyncWebSocketSession session)
{
    await session.SendTextAsync("Welcome!");
}

public override async Task OnSessionTextReceived(
    AsyncWebSocketSession session,
    string text)
{
    await session.SendTextAsync($"Echo: {text}");
}

public override async Task OnSessionBinaryReceived(
    AsyncWebSocketSession session,
    byte[] data,
    int offset,
    int count)
{
    await Task.CompletedTask;
}

public override async Task OnSessionClosed(
    AsyncWebSocketSession session)
{
    await base.OnSessionClosed(session);
}
```

Server instances can send to individual sessions or broadcast to all connected sessions:

```csharp
await server.SendTextToAsync(sessionKey, "Hello");

await server.BroadcastTextAsync("Message for everyone");
```

Binary equivalents are also available.

## QUIC

EonaCat.Network contains a QUIC implementation with connection and stream abstractions.

The main public types include:

- `QuicClient`
- `QuicServer`
- `QuicConnection`
- `QuicStream`
- `StreamType`
- QUIC packet and frame infrastructure
- QUIC settings and protocol helpers

### QUIC client

```csharp
using EonaCat.Quic;

var client = new QuicClient();

var connection = client.Connect("127.0.0.1", 11000);

var stream = connection.CreateStream(
    StreamType.ClientBidirectional);

stream.Send(
    System.Text.Encoding.UTF8.GetBytes("Hello QUIC"));
```

### QUIC server

```csharp
using EonaCat.Quic;

var server = new QuicServer("0.0.0.0", 11000);

server.OnClientConnected += connection =>
{
    Console.WriteLine("QUIC client connected");
};

server.Start();
```

> **Important:** the QUIC implementation is part of this library's own protocol stack. Validate the protocol behavior, interoperability and security characteristics against your application's requirements before using it for production Internet-facing workloads.

## `NetworkHelper`

For simple QUIC scenarios, `NetworkHelper` provides convenience methods:

```csharp
using EonaCat.Network;

NetworkHelper.QuicStartServer("0.0.0.0", 11000);

var stream = NetworkHelper.QuicStartClient(
    "127.0.0.1",
    11000);

NetworkHelper.QuicStopServer();
```

It also exposes events for:

- `OnQuicClientConnected`
- `OnQuicStreamOpened`
- `OnQuicStreamDataReceived`

The default global encoding is UTF-8:

```csharp
NetworkHelper.GlobalEncoding = System.Text.Encoding.UTF8;
```

## IPv4 and IPv6

The socket implementations support IPv4 and IPv6 where supported by the underlying .NET socket APIs.

The library also exposes:

```csharp
public enum IPType : byte
{
    IPv4,
    IPv6
}
```

TCP and UDP implementations expose IPv6-related information through their connection/remote information objects.

## TCP SSL/TLS

TCP clients and servers can use SSL/TLS.

Client example:

```csharp
var client = new SocketTcpClient();

await client.ConnectAsync(
    "127.0.0.1",
    5000,
    useSsl: true,
    sslOptions: new SslOptions());
```

The TCP server accepts a certificate and SSL options:

```csharp
var server = new SocketTcpServer(
    "0.0.0.0",
    5000,
    certificate,
    sslOptions);
```

Always use certificates and TLS settings appropriate for the environment in which the application is deployed.

## Dependencies

The package uses several EonaCat and .NET dependencies, including:

- EonaCat.Controls
- EonaCat.Json
- EonaCat.LogStack
- EonaCat.LogSystem
- EonaCat.Matchers
- EonaCat.Versioning
- System.Net.WebSockets
- System.Text.Encodings.Web

These are restored automatically when installing the NuGet package.

## License

EonaCat.Network is released under the **Apache License 2.0**.

See [LICENSE](LICENSE) for the complete license text.

Copyright © EonaCat (Jeroen Saey).