Friend spotlight!
Whimsical Animations course Friend spotlight!
NEW Whimsical Animations course Friend spotlight! NEW Whimsical Animations course
huge discount only this week Friend spotlight! Want to make your project stand out? NEW Whimsical Animations course huge discount only this week

Rust 代理模式讲解和代码示例

代理是一种结构型设计模式，让你能提供真实服务对象的替代品给客户端使用。代理接收客户端的请求并进行一些处理（访问控制和缓存等），然后再将请求传递给服务对象。

代理对象拥有和服务对象相同的接口，这使得当其被传递给客户端时可与真实对象互换。

进一步了解代理模式

Conceptual Example: Nginx Proxy

A web server such as Nginx can act as a proxy for your application server:

It provides controlled access to your application server.
It can do rate limiting.
It can do request caching.

server.rs

mod application;
mod nginx;

pub use nginx::NginxServer;

pub trait Server {
    fn handle_request(&mut self, url: &str, method: &str) -> (u16, String);
}

server/application.rs

use super::Server;

pub struct Application;

impl Server for Application {
    fn handle_request(&mut self, url: &str, method: &str) -> (u16, String) {
        if url == "/app/status" && method == "GET" {
            return (200, "Ok".into());
        }

        if url == "/create/user" && method == "POST" {
            return (201, "User Created".into());
        }

        (404, "Not Ok".into())
    }
}

server/nginx.rs

use std::collections::HashMap;

use super::{application::Application, Server};

/// NGINX server is a proxy to an application server.
pub struct NginxServer {
    application: Application,
    max_allowed_requests: u32,
    rate_limiter: HashMap<String, u32>,
}

impl NginxServer {
    pub fn new() -> Self {
        Self {
            application: Application,
            max_allowed_requests: 2,
            rate_limiter: HashMap::default(),
        }
    }

    pub fn check_rate_limiting(&mut self, url: &str) -> bool {
        let rate = self.rate_limiter.entry(url.to_string()).or_insert(1);

        if *rate > self.max_allowed_requests {
            return false;
        }

        *rate += 1;
        true
    }
}

impl Server for NginxServer {
    fn handle_request(&mut self, url: &str, method: &str) -> (u16, String) {
        if !self.check_rate_limiting(url) {
            return (403, "Not Allowed".into());
        }

        self.application.handle_request(url, method)
    }
}

main.rs

mod server;

use crate::server::{NginxServer, Server};

fn main() {
    let app_status = &"/app/status".to_string();
    let create_user = &"/create/user".to_string();

    let mut nginx = NginxServer::new();

    let (code, body) = nginx.handle_request(app_status, "GET");
    println!("Url: {}\nHttpCode: {}\nBody: {}\n", app_status, code, body);

    let (code, body) = nginx.handle_request(app_status, "GET");
    println!("Url: {}\nHttpCode: {}\nBody: {}\n", app_status, code, body);

    let (code, body) = nginx.handle_request(app_status, "GET");
    println!("Url: {}\nHttpCode: {}\nBody: {}\n", app_status, code, body);

    let (code, body) = nginx.handle_request(create_user, "POST");
    println!("Url: {}\nHttpCode: {}\nBody: {}\n", create_user, code, body);

    let (code, body) = nginx.handle_request(create_user, "GET");
    println!("Url: {}\nHttpCode: {}\nBody: {}\n", create_user, code, body);
}

Output

Url: /app/status
HttpCode: 200
Body: Ok

Url: /app/status
HttpCode: 200
Body: Ok

Url: /app/status
HttpCode: 403
Body: Not Allowed

Url: /create/user
HttpCode: 201
Body: User Created

Url: /create/user
HttpCode: 404
Body: Not Ok

代理在其他编程语言中的实现