Rust轻量级CoAP协议库coap的使用：高效实现物联网设备间的受限应用协议通信

coap-rs是一个用Rust实现的快速稳定的受限应用协议(CoAP)库，专为物联网设备间通信设计。

主要特性

• 支持CoAP核心协议RFC 7252
• 支持CoAP观察选项RFC 7641
• 支持"Too Many Requests"响应代码RFC 8516
• 支持块状传输RFC 7959
• 通过webrtc-rs支持DTLS安全传输
• 提供自定义客户端和服务器传输的选项

安装方法

在项目的Cargo.toml中添加以下依赖：

[dependencies]
coap = "0.22"       # CoAP协议主要实现
coap-lite = "0.13.3" # 轻量级CoAP实现
tokio = {version = "^1.32", features = ["full"]} # 异步运行时

基础示例

服务器端实现

use coap_lite::{RequestType as Method, CoapRequest};
use coap::Server;
use tokio::runtime::Runtime;
use std::net::SocketAddr;

fn main() {
    // 绑定本地5683端口(CoAP默认端口)
    let addr = "127.0.0.1:5683";
    
    // 创建Tokio运行时并启动异步服务
    Runtime::new().unwrap().block_on(async move {
        // 创建UDP协议CoAP服务器
        let mut server = Server::new_udp(addr).unwrap();
        println!("Server up on {}", addr);

        // 处理客户端请求
        server.run(|mut request: Box<CoapRequest<SocketAddr>>| async {
            // 匹配请求方法类型
            match request.get_method() {
                &Method::Get => println!("request by get {}", request.get_path()),
                &Method::Post => println!("request by post {}", 
                    String::from_utf8(request.message.payload.clone()).unwrap()),
                &Method::Put => println!("request by put {}", 
                    String::from_utf8(request.message.payload.clone()).unwrap()),
                _ => println!("request by other method"),
            };

            // 设置响应内容
            match request.response {
                Some(ref mut message) => {
                    message.message.payload = b"OK".to_vec();
                },
                _ => {}
            };
            return request
        }).await.unwrap();
    });
}

客户端实现

use coap_lite::{RequestType as Method, CoapRequest};
use coap::{UdpCoAPClient};
use tokio::main;

#[tokio::main]
async fn main() {
    // 定义请求URL
    let url = "coap://127.0.0.1:5683/Rust";
    println!("Client request: {}", url);

    // 发送GET请求并获取响应
    let response = UdpCoAPClient::get(url).await.unwrap();
    println!("Server reply: {}", 
        String::from_utf8(response.message.payload).unwrap());
}

完整示例

增强版服务器实现

use coap_lite::{RequestType as Method, CoapRequest};
use coap::Server;
use tokio::runtime::Runtime;
use std::net::SocketAddr;

fn main() {
    let addr = "127.0.0.1:5683";
    Runtime::new().unwrap().block_on(async move {
        let mut server = Server::new_udp(addr).unwrap();
        println!("CoAP server listening on {}", addr);

        server.run(|mut request: Box<CoapRequest<SocketAddr>>| async {
            match request.get_method() {
                &Method::Get => {
                    println!("GET request for path: {}", request.get_path());
                    // 特殊处理/time路径的请求
                    if request.get_path() == "/time" {
                        let time = chrono::Local::now().to_rfc2822();
                        request.response.as_mut().unwrap().message.payload = time.into_bytes();
                    }
                },
                &Method::Post => {
                    // 处理POST请求体
                    let payload = String::from_utf8(request.message.payload.clone()).unwrap();
                    println!("POST request with payload: {}", payload);
                    request.response.as_mut().unwrap().message.payload = b"POST received".to_vec();
                },
                &Method::Put => {
                    // 处理PUT请求体
                    let payload = String::from_utf8(request.message.payload.clone()).unwrap();
                    println!("PUT request with payload: {}", payload);
                    request.response.as_mut().unwrap().message.payload = b"PUT received".to_vec();
                },
                _ => {
                    println!("Unsupported method");
                    request.response.as_mut().unwrap().message.payload = b"Method not supported".to_vec();
                },
            };
            request
        }).await.unwrap();
    });
}

完整客户端实现

use coap::{UdpCoAPClient};
use tokio::main;

#[tokio::main]
async fn main() {
    // GET请求示例 - 获取服务器时间
    let url = "coap://127.0.0.1:5683/time";
    println!("Sending GET request to: {}", url);
    
    let response = UdpCoAPClient::get(url).await.unwrap();
    println!("Server response: {}", 
        String::from_utf8(response.message.payload).unwrap());

    // POST请求示例 - 发送数据到服务器
    let url = "coap://127.0.0.1:5683/data";
    println!("Sending POST request to: {}", url);
    
    let response = UdpCoAPClient::post(url, b"Hello CoAP!".to_vec()).await.unwrap();
    println!("Server response: {}", 
        String::from_utf8(response.message.payload).unwrap());

    // PUT请求示例 - 更新服务器数据
    let url = "coap://127.0.0.1:5683/data";
    println!("Sending PUT request to: {}", url);
    
    let response = UdpCoAPClient::put(url, b"Update data".to_vec()).await.unwrap();
    println!("Server response: {}", 
        String::from_utf8(response.message.payload).unwrap());
}

性能测试

使用以下命令运行基准测试：

cargo bench

许可证

本项目采用MIT开源许可证。