Proxy Pattern: Conpeptual example "Nginx Proxy"

Author: fadeevab

Cargo.toml

@@ -15,4 +15,5 @@ members = [
   "structural/decorator",
   "structural/facade",
   "structural/flyweight",
+  "structural/proxy",
 ]

structural/proxy/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+edition = "2021"
+name = "proxy"
+version = "0.1.0"
+
+[[bin]]
+name = "proxy"
+path = "main.rs"

structural/proxy/README.md

@@ -0,0 +1,31 @@
+# Proxy
+
+## Conceptual Example: Nginx Proxy
+
+```bash
+cargo run
+```
+
+## Execution Result
+
+```
+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
+```

structural/proxy/main.rs

@@ -0,0 +1,25 @@
+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);
+}

structural/proxy/server.rs

@@ -0,0 +1,8 @@
+mod application;
+mod nginx;
+
+pub use nginx::NginxServer;
+
+pub trait Server {
+    fn handle_request(&mut self, url: &String, method: &str) -> (u16, String);
+}

structural/proxy/server/application.rs

@@ -0,0 +1,17 @@
+use super::Server;
+
+pub struct Application;
+
+impl Server for Application {
+    fn handle_request(&mut self, url: &String, 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())
+    }
+}

structural/proxy/server/nginx.rs

@@ -0,0 +1,40 @@
+use std::collections::HashMap;
+
+use super::{application::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: &String) -> bool {
+        let rate = self.rate_limiter.entry(url.clone()).or_insert(1);
+
+        if *rate > self.max_allowed_requests {
+            return false;
+        }
+
+        *rate += 1;
+        return true;
+    }
+}
+
+impl Server for NginxServer {
+    fn handle_request(&mut self, url: &String, method: &str) -> (u16, String) {
+        if !self.check_rate_limiting(url) {
+            return (403, "Not Allowed".into());
+        }
+
+        return self.application.handle_request(url, method);
+    }
+}