Add proxy server logic

Author: RunjiaChen

myfirst.js

@@ -0,0 +1,70 @@
+const net = require("net");
+const server = net.createServer(); //creates an instance of a server
+
+server.on("connection", (clientToProxySocket) => { //once the connection is established, display message   
+    console.log("Client connected to proxy");
+    clientToProxySocket.once("data", (data) => { //once the client sends data, start the execution of the proxy servers 
+        let isConnectionTLS = data.toString().indexOf("CONNECT") !== -1; //check whether its a connect release
+
+        let serverPort = 80;
+        let serverAddress;
+
+        if (isConnectionTLS) {
+            serverPort = 443; //default port for https
+
+            serverAddress = data
+            .toString().split("CONNECT")[1]
+            .split(" ")[1]
+            .split(":")[0];
+        } else {
+            serverAddress = data.toString().split("Host: ")[1].split("\n")[0];
+        }
+
+        let proxyToServerSocket = net.createConnection(
+            {
+                host: serverAddress,
+                port: serverPort
+            },
+            () => {
+                console.log("Proxy to server is setup");
+            }
+        )
+
+        if (isConnectionTLS) {
+            clientToProxySocket.write("HTTP/1.1 200 OK\r\n\n"); //send response to client that connection is successful
+        } else {
+            proxyToServerSocket.write(data); //write data from client request to server
+        }
+
+        clientToProxySocket.pipe(proxyToServerSocket); //send data from client to server 
+        proxyToServerSocket.pipe(clientToProxySocket);// send data from server to client
+
+        proxyToServerSocket.on("error", (err) => { //check whether that is and error 
+            console.log("Proxy to server error");
+            console.log(err);
+        })
+
+        clientToProxySocket.on("error", (err) => {
+            console.log("Client to proxy error");
+        })
+    })
+})
+
+server.on("error", (err) => {
+    console.log("Internal server error");
+    console.log(err);
+})
+
+server.on("close", () => {
+    console.log("Client disconnected"); 
+})
+
+server.listen(
+    {
+        host: "0.0.0.0",
+        port: 3456, //sets the server to listen for connections on the port 3456
+    },
+    () => {
+        console.log("Server listening on 0.0.0.0:3456");
+    }
+);

package.json

@@ -0,0 +1,13 @@
+{
+  "name": "nodejs-forward-proxy-demo",
+  "version": "1.0.0",
+  "description": "",
+  "main": "myfirst.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "start": "node myfirst.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}