EventSourceClient: Robust Server-Sent Events (SSE) Client for .NET

The EventSourceClient library offers a comprehensive and easy-to-use implementation for consuming Server-Sent Events (SSE) in .NET applications. It's designed to efficiently handle real-time data streams, making it ideal for applications requiring seamless live updates like stock tickers, news feeds, or live notifications.

Features:

• Seamless Integration: Easily integrate with any .NET project to receive server-sent events.
• Resilience and Reliability: Features automatic reconnection logic to keep your application responsive and up-to-date despite network interruptions.
• Asynchronous Design: Utilizes an asynchronous API to ensure non-blocking operations, perfectly suited for modern C# applications.
• Flexible Configuration: Offers customizable options to alter client behavior to fit your needs, including custom headers for initial requests and adjustable reconnection times.
• Event Filtering: Capable of filtering and responding to specific event types directly from the server.
• Logging Support: Comes with integrated logging capabilities to assist in debugging and monitoring the client's behavior in production environments.
• Cross-Platform: Compatible with any platform that supports .NET Standard, including Windows, Linux, and macOS.

Getting Started:

To start receiving SSE, initialize the EventSourceClient with the server URL, configure your event handlers, and begin streaming. The client manages all connection and stream parsing aspects.

var eventSourceClient = new EventSourceClient(url, new HttpClient(), logger, new EventSourceExtraOptions());
Console.WriteLine("Client is now listening to the SSE server...");

eventSourceClient.EventReceived += (sender, e) => {
    Console.WriteLine($"Received Event: {e.Type}");
    Console.WriteLine($"Data: {e.Data}");
    Console.WriteLine($"ID: {e.Id}");
    if (e.Retry.HasValue) {
        Console.WriteLine($"Retry: {e.Retry.Value}");
    }
};

eventSourceClient.StateChanged += (sender, e) => Console.WriteLine($"State Changed: {e.ReadyState}");

await eventSourceClient.Stream();

AsyncEnumerable Sample:

The EventSourceClient also provides an AsyncEnumerable method for streaming events asynchronously. Here's an example of how to use it:

var eventSourceClient = new EventSourceClient(url, new HttpClient(), logger, new EventSourceExtraOptions());
Console.WriteLine("Client is now listening to the SSE server...");

await foreach (var eventArgs in eventSourceClient.StreamAsyncEnumerable())
{
    Console.WriteLine($"Received Event: {eventArgs.Type}");
    Console.WriteLine($"Data: {eventArgs.Data}");
    Console.WriteLine($"ID: {eventArgs.Id}");
}

In this example, we initialize the EventSourceClient as before. Instead of using the Stream method and handling events through event handlers, we use the StreamAsyncEnumerable method to asynchronously iterate over the events using the await foreach construct.

Each event is represented by a CustomEventArgs object, which contains the event type, data, and ID. You can process each event as needed within the loop.

Using the AsyncEnumerable approach provides a more concise and readable way to handle events, especially when you don't need to handle state changes or other events separately.

Use Cases:

• Real-time dashboards
• Live notifications in web and desktop applications
• Financial applications requiring live updates of market data
• Any application needing to efficiently consume live data feeds

Documentation:

For further details, please see the unit tests and sample code provided with the library.

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