如何防止读取时阻塞TcpStream？

Question

let listener = TcpListener::bind("localhost:1234").unwrap(); 
for stream in listener.incoming() { 
    let s = stream.unwrap(); 
    handle_stream(s); 
} 

fn handle_stream(mut stream: TcpStream) ->() { 
    let mut buf = [0]; 
    loop { 
     let _ = match stream.read(&mut buf) { 
      Err(e) => panic!("Got an error: {}", e), 
      Ok(m) => { 
       println!("Received {:?}, {:?}", m, buf); 
       if m == 0 { 
        // doesn't reach here. 
        break; 
       } 
       m 
      }, 
     }; 
    } 
} 

然后我通过运行curl http://localhost:1234连接到服务器。

我预计Ok(0)将被返回，但它没有达到该声明，而是挂起。如果这是一个EOF，在这种情况下我该如何处理？

Answer 1

你想用TcpStream::set_read_timeout，然后检查是否有特定类型的错误：

use std::io::{self, Read}; 
use std::net::{TcpListener, TcpStream}; 
use std::time::Duration; 

fn main() { 
    let listener = TcpListener::bind("localhost:1234").unwrap(); 
    for stream in listener.incoming() { 
     let s = stream.unwrap(); 
     handle_stream(s); 
    } 

    fn handle_stream(mut stream: TcpStream) ->() { 
     let mut buf = [0]; 
     stream.set_read_timeout(Some(Duration::from_millis(100))).unwrap(); 
     loop { 
      let _ = match stream.read(&mut buf) { 
       Err(e) => { 
        match e.kind() { 
         io::ErrorKind::WouldBlock => { 
          println!("would have blocked"); 
          break; 
         }, 
         _ => panic!("Got an error: {}", e), 
        } 
       }, 
       Ok(m) => { 
        println!("Received {:?}, {:?}", m, buf); 
        if m == 0 { 
         // doesn't reach here. 
         break; 
        } 
        m 
       }, 
      }; 
     } 
    } 
}