README.md

# Chat Example

This directory contains a full stack example of a simple chat webapp using nhooyr.io/websocket.

```bash
$ cd chat-example
$ go run . localhost:0
listening on http://127.0.0.1:51055
```

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

![Image of Example](https://i.imgur.com/VwJl9Bh.png)

## 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.