esp-connect

Cargo.lock

@@ -1090,6 +1090,13 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "esp-connect"
+version = "0.1.0"
+dependencies = [
+ "tokio",
+]
+
 [[package]]
 name = "etcetera"
 version = "0.8.0"
@@ -3118,9 +3125,21 @@ dependencies = [
  "pin-project-lite",
  "signal-hook-registry",
  "socket2",
+ "tokio-macros",
  "windows-sys 0.52.0",
 ]
 
+[[package]]
+name = "tokio-macros"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "693d596312e88961bc67d7f1f97af8a70227d9f90c31bba5806eec004978d752"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.79",
+]
+
 [[package]]
 name = "tokio-stream"
 version = "0.1.16"

Cargo.toml

@@ -5,4 +5,5 @@ members = [
     "crates/xtask",
     "crates/migration",
     "crates/entity",
+    "crates/esp-connect",
 ]

crates/esp-connect/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "esp-connect"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+tokio = { version = "*", features = ["full"] }

crates/esp-connect/src/main.rs

@@ -0,0 +1,73 @@
+//! A "hello world" echo server with Tokio
+//!
+//! This server will create a TCP listener, accept connections in a loop, and
+//! write back everything that's read off of each TCP connection.
+//!
+//! Because the Tokio runtime uses a thread pool, each TCP connection is
+//! processed concurrently with all other TCP connections across multiple
+//! threads.
+//!
+//! To see this server in action, you can run this in one terminal:
+//!
+//!     cargo run --example echo
+//!
+//! and in another terminal you can run:
+//!
+//!     cargo run --example connect 127.0.0.1:8080
+//!
+//! Each line you type in to the `connect` terminal should be echo'd back to
+//! you! If you open up multiple terminals running the `connect` example you
+//! should be able to see them all make progress simultaneously.
+
+#![warn(rust_2018_idioms)]
+
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpListener;
+
+use core::str;
+use std::env;
+use std::error::Error;
+
+#[tokio::main]
+async fn main() -> std::io::Result<()> {
+    // Allow passing an address to listen on as the first argument of this
+    // program, but otherwise we'll just set up our TCP listener on
+    // 127.0.0.1:8080 for connections.
+    let addr = String::from("0.0.0.0:7999");
+
+    // Next up we create a TCP listener which will listen for incoming
+    // connections. This TCP listener is bound to the address we determined
+    // above and must be associated with an event loop.
+    let listener = TcpListener::bind(&addr).await?;
+    println!("Listening on: {}", addr);
+
+    loop {
+        // Asynchronously wait for an inbound socket.
+        let (mut socket, _) = listener.accept().await?;
+        println!("Connection Established");
+
+        // And this is where much of the magic of this server happens. We
+        // crucially want all clients to make progress concurrently, rather than
+        // blocking one on completion of another. To achieve this we use the
+        // `tokio::spawn` function to execute the work in the background.
+        //
+        // Essentially here we're executing a new task to run concurrently,
+        // which will allow all of our clients to be processed concurrently.
+
+        let mut buf = vec![0; 1024];
+
+        // In a loop, read data from the socket and write the data back.
+        loop {
+            let n = socket
+                .read(&mut buf)
+                .await
+                .expect("failed to read data from socket");
+
+            if n == 0 {
+                return Ok(());
+            }
+
+            println!("{}", str::from_utf8(&buf).unwrap())
+        }
+    }
+}