# coap-rs
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A fast and stable [Constrained Application Protocol(CoAP)](https://tools.ietf.org/html/rfc7252) library implemented in Rust.
Features:
- CoAP core protocol [RFC 7252](https://tools.ietf.org/rfc/rfc7252.txt)
- CoAP Observe option [RFC 7641](https://tools.ietf.org/rfc/rfc7641.txt)
- *Too Many Requests* Response Code [RFC 8516](https://tools.ietf.org/html/rfc8516)
- Block-Wise Transfers [RFC 7959](https://tools.ietf.org/html/rfc7959)
- DTLS support via [webrtc-rs](https://github.com/webrtc-rs/webrtc)
- Option to provide custom transports for client and server
[Documentation](https://docs.rs/coap/)
## Installation
First add this to your `Cargo.toml`:
```toml
[dependencies]
coap = "0.27"
coap-lite = "0.13.3"
tokio = {version = "^1.32", features = ["full"]}
```
## Example
### Server:
```rust
use coap::{
router::{
extract::{Json, Path, Query, State},
get, post, Router,
},
Server,
};
use serde::Deserialize;
use std::{collections::HashMap, sync::Arc};
use tokio::sync::Mutex;
#[derive(Debug, Clone, Default)]
pub struct RoomState {
rooms: HashMap<String, f64>,
}
pub type RoomMutex = Arc<Mutex<RoomState>>;
#[derive(Debug, Deserialize)]
pub struct QueryArgs {
room: String,
}
async fn get_temperature(
Query(QueryArgs { room }): Query<QueryArgs>,
state: State<RoomMutex>,
) -> String {
let state = state.lock().await;
if let Some(temp) = state.rooms.get(&room) {
format!("Temperature in {room}: {temp}")
} else {
format!("Room {} not found", room)
}
}
async fn set_temperature(
Path(room): Path<String>,
Json(temp): Json<f64>,
State(state): State<RoomMutex>,
) -> String {
let mut state = state.lock().await;
state.rooms.insert(room, temp);
"OK".to_string()
}
#[tokio::main]
async fn main() {
let addr = "127.0.0.1:5683";
let state = Arc::new(Mutex::new(RoomState {
rooms: HashMap::new(),
}));
let router = Router::new()
.route("/temperature", get(get_temperature))
.route("/temperature/{room}", post(set_temperature))
.with_state(state);
let server = Server::new_udp(addr).unwrap();
println!("Server up on {addr}");
server.serve(router).await.unwrap();
}
```
### Client:
```rust
use coap::UdpCoAPClient;
#[tokio::main]
async fn main() {
let url = "coap://127.0.0.1:5683/temperature?room=kitchen";
println!("Client request: {}", url);
let response = UdpCoAPClient::get(url).await.unwrap();
println!("Server reply: {}", String::from_utf8(response.message.payload).unwrap());
}
```
## Benchmark
```bash
$ cargo bench
```