README.md

title	keywords	description
Server-Sent Events	sse server-sent events real-time	Implementing Server-Sent Events in an application.

Server-Sent Events with Fiber

This example demonstrates how to implement Server-Sent Events (SSE) in a Fiber application.

Description

Server-Sent Events (SSE) allow servers to push updates to the client over a single HTTP connection. This is useful for real-time applications where the server needs to continuously send data to the client, such as live feeds, notifications, or real-time charts.

Prerequisites

• Go 1.16 or higher
• Go modules

Setup

1. Clone the repository:

   git clone https://github.com/gofiber/recipes.git
   cd recipes/sse

2. Install dependencies:

   go mod tidy

Running the Application

1. Run the application:

   go run main.go

2. The server will start on http://localhost:3000.

Endpoints

• GET /: Index page
• GET /sse: SSE route
• PUT /publish: Send messages via SSE

Example Usage

By default, the example will run on port 3000; this can be changed by modifying the appPort constant in main.go

1. Open your browser and navigate to http://localhost:3000.
2. The client will automatically connect to the SSE endpoint and start receiving updates from the server.
3. The /sse endpoint will publish the current time to the client every two seconds

Custom Messages

To send a custom message, send a PUT request to the /publish endpoint in the following JSON format

{
  "message": "Hello, World!"
}

Messages sent to the /publish endpoint will be added to a queue that is read from in FIFO order. You can test this by using curl in an iterator

If you are using the Bash or Zsh shell:

for i in {1..10}; do
  curl -X PUT -H 'Content-type: application/json' --data "{\"message\":\"SSE TEST $i\"}" http://localhost:3000/publish
done

If you are using fish:

for i in (seq 1 10)
  curl -X PUT -H 'Content-type: application/json' --data "{\"message\":\"SSE TEST $i\"}" http://localhost:3000/publish
end

Once published, your added messages will begin appearing in the output at http://localhost:3000. Once the queue is empty and no user-published messages are left, /sse will return to it's standard behavior of displaying the current time.

Code Overview

main.go

The main Go file sets up the Fiber application and handles the SSE connections. It includes the necessary configuration to send events to the client.

Additional Information

Server-Sent Events (SSE) is a standard allowing servers to push data to web clients over HTTP. Unlike WebSockets, which require a full-duplex connection, SSE uses a unidirectional connection from the server to the client. This makes SSE simpler to implement and more efficient for scenarios where only the server needs to send updates.

For more information on SSE, you can refer to the following resources:

• Server-Sent Events on MDN
• Server-Sent Events on Wikipedia