Struct std::net::TcpStream

pub struct TcpStream(_);

A TCP stream between a local and a remote socket.

After creating a TcpStream by either connecting to a remote host or accepting a connection on a TcpListener, data can be transmitted by reading and writing to it.

The connection will be closed when the value is dropped. The reading and writing portions of the connection can also be shut down individually with the shutdown method.

The Transmission Control Protocol is specified in IETF RFC 793.

Examples

use std::io::prelude::*;
use std::net::TcpStream;

fn main() -> std::io::Result<()> {
    let mut stream = TcpStream::connect("127.0.0.1:34254")?;

    stream.write(&[1])?;
    stream.read(&mut [0; 128])?;
    Ok(())
} // the stream is closed here

Implementations

impl TcpStream

pub fn connect<A: ToSocketAddrs>(addr: A) -> Result<TcpStream>

Opens a TCP connection to a remote host.

addr is an address of the remote host. Anything which implements ToSocketAddrs trait can be supplied for the address; see this trait documentation for concrete examples.

If addr yields multiple addresses, connect will be attempted with each of the addresses until a connection is successful. If none of the addresses result in a successful connection, the error returned from the last connection attempt (the last address) is returned.

Examples

Open a TCP connection to 127.0.0.1:8080:

use std::net::TcpStream;

if let Ok(stream) = TcpStream::connect("127.0.0.1:8080") {
    println!("Connected to the server!");
} else {
    println!("Couldn't connect to server...");
}

Open a TCP connection to 127.0.0.1:8080. If the connection fails, open a TCP connection to 127.0.0.1:8081:

use std::net::{SocketAddr, TcpStream};

let addrs = [
    SocketAddr::from(([127, 0, 0, 1], 8080)),
    SocketAddr::from(([127, 0, 0, 1], 8081)),
];
if let Ok(stream) = TcpStream::connect(&addrs[..]) {
    println!("Connected to the server!");
} else {
    println!("Couldn't connect to server...");
}

pub fn connect_timeout(
    addr: &SocketAddr,
    timeout: Duration
) -> Result<TcpStream>

Opens a TCP connection to a remote host with a timeout.

Unlike connect, connect_timeout takes a single SocketAddr since timeout must be applied to individual addresses.

It is an error to pass a zero Duration to this function.

Unlike other methods on TcpStream, this does not correspond to a single system call. It instead calls connect in nonblocking mode and then uses an OS-specific mechanism to await the completion of the connection request.

pub fn peer_addr(&self) -> Result<SocketAddr>

Returns the socket address of the remote peer of this TCP connection.

Examples

use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, TcpStream};

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
assert_eq!(stream.peer_addr().unwrap(),
           SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080)));

pub fn local_addr(&self) -> Result<SocketAddr>

Returns the socket address of the local half of this TCP connection.

Examples

use std::net::{IpAddr, Ipv4Addr, TcpStream};

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
assert_eq!(stream.local_addr().unwrap().ip(),
           IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)));

pub fn shutdown(&self, how: Shutdown) -> Result<()>

Shuts down the read, write, or both halves of this connection.

This function will cause all pending and future I/O on the specified portions to return immediately with an appropriate value (see the documentation of Shutdown).

Platform-specific behavior

Calling this function multiple times may result in different behavior, depending on the operating system. On Linux, the second call will return Ok(()), but on macOS, it will return ErrorKind::NotConnected. This may change in the future.

Examples

use std::net::{Shutdown, TcpStream};

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.shutdown(Shutdown::Both).expect("shutdown call failed");

pub fn try_clone(&self) -> Result<TcpStream>

Creates a new independently owned handle to the underlying socket.

The returned TcpStream is a reference to the same stream that this object references. Both handles will read and write the same stream of data, and options set on one stream will be propagated to the other stream.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
let stream_clone = stream.try_clone().expect("clone failed...");

pub fn set_read_timeout(&self, dur: Option<Duration>) -> Result<()>

Sets the read timeout to the timeout specified.

If the value specified is None, then read calls will block indefinitely. An Err is returned if the zero Duration is passed to this method.

Platform-specific behavior

Platforms may return a different error code whenever a read times out as a result of setting this option. For example Unix typically returns an error of the kind WouldBlock, but Windows may return TimedOut.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_read_timeout(None).expect("set_read_timeout call failed");

An Err is returned if the zero Duration is passed to this method:

use std::io;
use std::net::TcpStream;
use std::time::Duration;

let stream = TcpStream::connect("127.0.0.1:8080").unwrap();
let result = stream.set_read_timeout(Some(Duration::new(0, 0)));
let err = result.unwrap_err();
assert_eq!(err.kind(), io::ErrorKind::InvalidInput)

pub fn set_write_timeout(&self, dur: Option<Duration>) -> Result<()>

Sets the write timeout to the timeout specified.

If the value specified is None, then write calls will block indefinitely. An Err is returned if the zero Duration is passed to this method.

Platform-specific behavior

Platforms may return a different error code whenever a write times out as a result of setting this option. For example Unix typically returns an error of the kind WouldBlock, but Windows may return TimedOut.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_write_timeout(None).expect("set_write_timeout call failed");

An Err is returned if the zero Duration is passed to this method:

use std::io;
use std::net::TcpStream;
use std::time::Duration;

let stream = TcpStream::connect("127.0.0.1:8080").unwrap();
let result = stream.set_write_timeout(Some(Duration::new(0, 0)));
let err = result.unwrap_err();
assert_eq!(err.kind(), io::ErrorKind::InvalidInput)

pub fn read_timeout(&self) -> Result<Option<Duration>>

Returns the read timeout of this socket.

If the timeout is None, then read calls will block indefinitely.

Platform-specific behavior

Some platforms do not provide access to the current timeout.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_read_timeout(None).expect("set_read_timeout call failed");
assert_eq!(stream.read_timeout().unwrap(), None);

pub fn write_timeout(&self) -> Result<Option<Duration>>

Returns the write timeout of this socket.

If the timeout is None, then write calls will block indefinitely.

Platform-specific behavior

Some platforms do not provide access to the current timeout.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_write_timeout(None).expect("set_write_timeout call failed");
assert_eq!(stream.write_timeout().unwrap(), None);

pub fn peek(&self, buf: &mut [u8]) -> Result<usize>

Receives data on the socket from the remote address to which it is connected, without removing that data from the queue. On success, returns the number of bytes peeked.

Successive calls return the same data. This is accomplished by passing MSG_PEEK as a flag to the underlying recv system call.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8000")
                       .expect("couldn't bind to address");
let mut buf = [0; 10];
let len = stream.peek(&mut buf).expect("peek failed");

pub fn set_nodelay(&self, nodelay: bool) -> Result<()>

Sets the value of the TCP_NODELAY option on this socket.

If set, this option disables the Nagle algorithm. This means that segments are always sent as soon as possible, even if there is only a small amount of data. When not set, data is buffered until there is a sufficient amount to send out, thereby avoiding the frequent sending of small packets.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_nodelay(true).expect("set_nodelay call failed");

pub fn nodelay(&self) -> Result<bool>

Gets the value of the TCP_NODELAY option on this socket.

For more information about this option, see TcpStream::set_nodelay.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_nodelay(true).expect("set_nodelay call failed");
assert_eq!(stream.nodelay().unwrap_or(false), true);

pub fn set_ttl(&self, ttl: u32) -> Result<()>

Sets the value for the IP_TTL option on this socket.

This value sets the time-to-live field that is used in every packet sent from this socket.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_ttl(100).expect("set_ttl call failed");

pub fn ttl(&self) -> Result<u32>

Gets the value of the IP_TTL option for this socket.

For more information about this option, see TcpStream::set_ttl.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.set_ttl(100).expect("set_ttl call failed");
assert_eq!(stream.ttl().unwrap_or(0), 100);

pub fn take_error(&self) -> Result<Option<Error>>

Gets the value of the SO_ERROR option on this socket.

This will retrieve the stored error in the underlying socket, clearing the field in the process. This can be useful for checking errors between calls.

Examples

use std::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080")
                       .expect("Couldn't connect to the server...");
stream.take_error().expect("No error was expected...");

pub fn set_nonblocking(&self, nonblocking: bool) -> Result<()>

Moves this TCP stream into or out of nonblocking mode.

This will result in read, write, recv and send operations becoming nonblocking, i.e., immediately returning from their calls. If the IO operation is successful, Ok is returned and no further action is required. If the IO operation could not be completed and needs to be retried, an error with kind io::ErrorKind::WouldBlock is returned.

On Unix platforms, calling this method corresponds to calling fcntl FIONBIO. On Windows calling this method corresponds to calling ioctlsocket FIONBIO.

Examples

Reading bytes from a TCP stream in non-blocking mode:

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

let mut stream = TcpStream::connect("127.0.0.1:7878")
    .expect("Couldn't connect to the server...");
stream.set_nonblocking(true).expect("set_nonblocking call failed");

let mut buf = vec![];
loop {
    match stream.read_to_end(&mut buf) {
        Ok(_) => break,
        Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
            // wait until network socket is ready, typically implemented
            // via platform-specific APIs such as epoll or IOCP
            wait_for_fd();
        }
        Err(e) => panic!("encountered IO error: {}", e),
    };
};
println!("bytes: {:?}", buf);

Trait Implementations

impl Debug for TcpStream

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Read for TcpStream

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬 This is a nightly-only experimental API. (can_vector #69941)

Determines if this Reader has an efficient read_vectored implementation.

unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer #42788)

Determines if this Reader can work with buffers of uninitialized memory.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a “by reference” adapter for this instance of Read.

fn bytes(self) -> Bytes<Self> where
    Self: Sized, 

Transforms this Read instance to an Iterator over its bytes.

fn chain<R: Read>(self, next: R) -> Chain<Self, R> where
    Self: Sized, 

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self> where
    Self: Sized, 

Creates an adapter which will read at most limit bytes from it.

impl Read for &TcpStream

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬 This is a nightly-only experimental API. (can_vector #69941)

Determines if this Reader has an efficient read_vectored implementation.

unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer #42788)

Determines if this Reader can work with buffers of uninitialized memory.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a “by reference” adapter for this instance of Read.

fn bytes(self) -> Bytes<Self> where
    Self: Sized, 

Transforms this Read instance to an Iterator over its bytes.

fn chain<R: Read>(self, next: R) -> Chain<Self, R> where
    Self: Sized, 

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self> where
    Self: Sized, 

Creates an adapter which will read at most limit bytes from it.

impl Write for TcpStream

fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬 This is a nightly-only experimental API. (can_vector #69941)

Determines if this Writer has an efficient write_vectored implementation.

fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>

🔬 This is a nightly-only experimental API. (write_all_vectored #70436)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a “by reference” adapter for this instance of Write.

impl Write for &TcpStream

fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬 This is a nightly-only experimental API. (can_vector #69941)

Determines if this Writer has an efficient write_vectored implementation.

fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_all(&mut self, buf: &[u8]) -> Result<()>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>

🔬 This is a nightly-only experimental API. (write_all_vectored #70436)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self where
    Self: Sized, 

Creates a “by reference” adapter for this instance of Write.