chat

Chat Example

This directory contains a full stack example of a simple chat webapp using github.com/coder/websocket.

$ cd examples/chat
$ go run . localhost:0
listening on ws://127.0.0.1:51055

Visit the printed URL to submit and view broadcasted messages in a browser.

Structure

The frontend is contained in index.html, index.js and index.css. It sets up the DOM with a scrollable div at the top that is populated with new messages as they are broadcast. At the bottom it adds a form to submit messages.

The messages are received via the WebSocket /subscribe endpoint and published via the HTTP POST /publish endpoint. The reason for not publishing messages over the WebSocket is so that you can easily publish a message with curl.

The server portion is main.go and chat.go and implements serving the static frontend assets, the /subscribe WebSocket endpoint and the HTTP POST /publish endpoint.

The code is well commented. I would recommend starting in main.go and then chat.go followed by index.html and then index.js.

There are two automated tests for the server included in chat_test.go. The first is a simple one client echo test. It publishes a single message and ensures it's received.

The second is a complex concurrency test where 10 clients send 128 unique messages of max 128 bytes concurrently. The test ensures all messages are seen by every client.