Server-Sent Events Writer

sse is a lightweight Go library for writing Server-Sent Events (SSE). This library allows easy integration of SSE into web servers, providing real-time updates to connected clients.

Installation

To install the sse package, use the following command:

go get github.com/floriscornel/sse

Usage

Importing the Package

import (
    "net/http"
    "github.com/floriscornel/sse"
)

Creating a Server-Sent Events Writer

To create an SSE writer, use the NewResponseWriter function. This function requires an http.ResponseWriter and options to configure the SSE writer.

opts := sse.Options{
    ResponseStatus: http.StatusOK,
    Encoding:       sse.EncodeNone,
}

func handler(w http.ResponseWriter, r *http.Request) {
    sseWriter := sse.NewResponseWriter(w, opts)

    for {
        err := sseWriter.Write("message", map[string]string{"hello": "world"})
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }
        time.Sleep(2 * time.Second)
    }
}

http.HandleFunc("/events", handler)
log.Fatal(http.ListenAndServe(":8080", nil))

Encoding Options

The sse package supports various encoding options to compress the data sent to clients. Available encoding options include:

• EncodeNone
• EncodeDeflate
• EncodeCompress
• EncodeGzip
• EncodeBrotli
• EncodeZstd

Specify the desired encoding in the Options struct:

opts := sse.Options{
    ResponseStatus: http.StatusOK,
    Encoding:       sse.EncodeGzip,
}

Examples

You can find more examples in the examples directory. To run an example, navigate to the respective directory and execute the following command:

go run main.go

Example Structure

• ping: A simple example of sending periodic ping messages to the client.
• incremental-updates: Demonstrates sending incremental updates to the client with different event types.
• number-of-listeners: Implements a counter to track the number of connected clients.

Contributing

Contributions are welcome! Feel free to open issues or submit pull requests. For major changes, please open an issue first to discuss what you would like to change.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Contact

If you have any questions, feel free to reach out:

• Author: Floris Cornel
• Email: floris@cornel.email
• GitHub: github.com/floriscornel/sse