Use commandline args to run rserver logic added

src/main.rs

@@ -1,6 +1,35 @@
 mod lib;
+use std::env;
 
 fn main() {
-    let (server_host, server_port) = ("127.0.0.1", 80);
+    /* 
+    let us declare default local server host and sever port 
+    that will be used in case not all commandline args are passed .
+    */
+    let (mut server_host, mut server_port) = ("127.0.0.1", 80);
+    // let us add logic to get local server host and sever port from command line.
+    // RServer will run at the input server host and server port.
+    let args = env::args().collect::<Vec<String>>();    // args is  a Vector of String
+    // let us check command line argument length , it should be 3 as 1st argument is the command used to invoke the program
+    if args.len() < 3 {
+        println!("Error - Not enough arguments supplied.\nPlease specify local server host and port as command-line arguments.");
+        println!("Using default host '{}' and port '{}'.", server_host, server_port);
+    } else {
+        // First assign the server host
+        server_host = &args[1];
+        // Second assign the 
+        server_port = match args[2].trim().parse() {
+            Ok(num) => num,
+            Err(_) => {     // handle error and continue the program
+                println!("Error - Pass port as number.");
+                println!("Using default port '{}'", server_port);
+                // return default port value
+                server_port
+            }
+        };
+
+    }
+    // println!("server_host: {}", server_host);
+    // println!("server_port: {}", server_port);
     lib::start_server(server_host, server_port);
 }