# WebSockets in Rust

> Part one of a Rust series: a WebSocket server built on the ws crate.

- URL: https://seanbehan.ca/posts/websockets-rust
- Author: Sean Behan
- Published: November 27, 2019
- Tags: programming, rust, websocket
- Reading time: 2 minutes

---

### Introduction

Today I'll show you how you can write incredibly fast code in Rust. This is

part one of a tutorial series.

This is an intermediate tutorial, if you are unfamiliar with Rust basics I

would suggest reading the Rust book for free at [https://doc.rust-lang.org/stable/book/](https://doc.rust-lang.org/stable/book/).

### Project Setup

Lets dive right in.

```bash
cargo new rust-tutorial
cd rust-tutorial
```

Let's build our websocket server.

Edit your `Cargo.toml` and add [`ws`](https://docs.rs/ws/) to your

`[dependencies]`.

Your `Cargo.toml` should now look something like this.

```toml
[package]
name = "rust-tutorial"
version = "0.1.0"
authors = ["Sean Behan <codebam@riseup.net>"]
edition = "2018"

[dependencies]
ws = "*"
```

### Building the WebSocket Server

Import our libraries.

```rust
use ws::listen;
```

Start a websocket listener.

```rust
fn main() {
    listen("127.0.0.1:5000", |out| {
        move |msg: ws::Message| {
            // handle the msg here
        }
    }
}
```

### Handling Messages

We'll respond to recieved messages and just echo them back for now.

Of course you could easily pass this data into any function and use it to

generate a response. In fact the incoming and outgoing data doesn't even have

to be text.

```rust
out.send(format!("recieved message: {}", msg.into_text().unwrap())).unwrap();
out.close(ws::CloseCode::Normal)
```

### Testing the Server

If we connect to this now using websocat, which can be installed with `cargo

install websocat`, we can see the server echos back messages that we send to

it.

```sh
$ websocat ws://127.0.0.1:5000
hello world
recieved message: hello world
```

This isn't that interesting. It's cool that we can do all this in just 8 lines

of Rust though!

### Next Steps

In the next part of this series I'll show you how to use use

[`tokio`](https://docs.rs/tokio/) to create an asyncronous server so we can

manage simultaneous connections. Stay tuned!