mirror of
https://github.com/tokio-rs/tokio.git
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73 lines
2.0 KiB
Rust
73 lines
2.0 KiB
Rust
//! A UDP client that just sends everything it gets via `stdio` in a single datagram, and then
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//! waits for a reply.
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//!
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//! For the reasons of simplicity data from `stdio` is read until `EOF` in a blocking manner.
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//!
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//! You can test this out by running an echo server:
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//!
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//! ```
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//! $ cargo run --example echo-udp -- 127.0.0.1:8080
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//! ```
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//!
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//! and running the client in another terminal:
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//!
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//! ```
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//! $ cargo run --example udp-client
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//! ```
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//!
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//! You can optionally provide any custom endpoint address for the client:
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//!
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//! ```
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//! $ cargo run --example udp-client -- 127.0.0.1:8080
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//! ```
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//!
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//! Don't forget to pass `EOF` to the standard input of the client!
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//!
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//! Please mind that since the UDP protocol doesn't have any capabilities to detect a broken
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//! connection the server needs to be run first, otherwise the client will block forever.
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#![warn(rust_2018_idioms)]
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use std::env;
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use std::error::Error;
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use std::io::{stdin, Read};
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use std::net::SocketAddr;
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use tokio::net::UdpSocket;
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fn get_stdin_data() -> Result<Vec<u8>, Box<dyn std::error::Error>> {
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let mut buf = Vec::new();
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stdin().read_to_end(&mut buf)?;
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Ok(buf)
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}
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#[tokio::main]
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async fn main() -> Result<(), Box<dyn Error>> {
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let remote_addr: SocketAddr = env::args()
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.nth(1)
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.unwrap_or_else(|| "127.0.0.1:8080".into())
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.parse()?;
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// We use port 0 to let the operating system allocate an available port for us.
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let local_addr: SocketAddr = if remote_addr.is_ipv4() {
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"0.0.0.0:0"
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} else {
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"[::]:0"
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}
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.parse()?;
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let mut socket = UdpSocket::bind(local_addr).await?;
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const MAX_DATAGRAM_SIZE: usize = 65_507;
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socket.connect(&remote_addr).await?;
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let data = get_stdin_data()?;
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socket.send(&data).await?;
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let mut data = vec![0u8; MAX_DATAGRAM_SIZE];
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let len = socket.recv(&mut data).await?;
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println!(
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"Received {} bytes:\n{}",
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len,
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String::from_utf8_lossy(&data[..len])
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);
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Ok(())
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}
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