examples/tcp-echo-server/src/main.rs

   1 use async_std::task;
   2 use connect::tcp::TcpListener;
   3 use connect::{ConnectDatagram, SinkExt, StreamExt};
   4 use log::*;
   5 use std::env;
   6
   7 #[async_std::main]
   8 async fn main() -> anyhow::Result<()> {
   9     env_logger::init();
  10
  11     // Get ip address from cmd line args
  12     let args: Vec<String> = env::args().collect();
  13
  14     let ip_address = match args.get(1) {
  15         Some(addr) => addr,
  16         None => {
  17             error!("Need to pass IP address to bind to as command line argument");
  18             panic!();
  19         }
  20     };
  21
  22     // create a server
  23     let mut server = TcpListener::bind(ip_address).await?;
  24
  25     // handle server connections
  26     // wait for a connection to come in and be accepted
  27     while let Some(mut conn) = server.next().await {
  28         info!("Handling connection from {}", conn.peer_addr());
  29
  30         task::spawn(async move {
  31             while let Some(envelope) = conn.reader().next().await {
  32                 // handle message based on intended recipient
  33                 if envelope.tag() == 65535 {
  34                     // if recipient is 65535, we do custom processing
  35                     let data = envelope.data().to_vec();
  36                     let msg =
  37                         String::from_utf8(data).expect("could not build String from payload bytes");
  38                     info!("Received a message \"{}\" from {}", msg, conn.peer_addr());
  39
  40                     let reply = ConnectDatagram::with_tag(envelope.tag(), msg.into_bytes())
  41                         .expect("could not construct new datagram from built String");
  42
  43                     conn.writer()
  44                         .send(reply)
  45                         .await
  46                         .expect("Could not send message back to source connection");
  47                     info!("Sent message back to original sender");
  48                 } else {
  49                     // if recipient is anything else, we just send it back
  50                     warn!(
  51                         "Received a message for unknown recipient {} from {}",
  52                         envelope.tag(),
  53                         conn.peer_addr()
  54                     );
  55
  56                     conn.writer()
  57                         .send(envelope)
  58                         .await
  59                         .expect("Could not send message back to source connection");
  60                     info!("Sent message back to original sender");
  61                 }
  62             }
  63         });
  64     }
  65
  66     Ok(())
  67 }