(server) chore:Complete basic message receive and send logic (#5)

Server/src/network_service/tcp_server.rs

@@ -1,4 +1,4 @@
-use tokio::io::AsyncWriteExt;
+use tokio::io::{ErrorKind, Interest};
 use tokio::net::{TcpListener, TcpStream};
 
 pub(crate) struct TcpServer;
@@ -20,10 +20,44 @@ impl TcpServer {
         }
     }
 
-    async fn process(mut socket: TcpStream) {
-        socket
-            .write_all("Hello from server written in Rust!".as_bytes())
-            .await
-            .unwrap();
+    async fn process(socket: TcpStream) {
+        loop {
+            match socket.ready(Interest::READABLE | Interest::WRITABLE).await {
+                Ok(ready) => {
+                    if ready.is_readable() {
+                        let mut buffer = Vec::with_capacity(1024);
+                        match socket.try_read_buf(&mut buffer) {
+                            // We need to write to client after reading from that,
+                            // so we use `continue` here instead if `break`.
+                            Ok(_) => {
+                                log::info!("Received contents");
+
+                                // TODO: Start dispatching messages here.
+
+                                continue;
+                            }
+                            Err(e) if e.kind() == ErrorKind::WouldBlock => continue,
+                            Err(e) => {
+                                log::error!("Failed to read from TCP client socket: {e}");
+
+                                break;
+                            }
+                        }
+                    }
+                    if ready.is_writable() {
+                        match socket.try_write(b"Hello from server written in Rust!") {
+                            Ok(_) => break,
+                            Err(e) if e.kind() == ErrorKind::WouldBlock => continue,
+                            Err(e) => {
+                                log::error!("Failed to write to TCP client socket: {e}");
+
+                                break;
+                            }
+                        }
+                    }
+                }
+                Err(e) => log::error!("Failed to wait for any states: {e}"),
+            }
+        }
     }
 }