Trait std::net::ToSocketAddrs
1.0.0 · source · pub trait ToSocketAddrs {
type Iter: Iterator<Item = SocketAddr>;
// Required method
fn to_socket_addrs(&self) -> Result<Self::Iter>;
}
Expand description
A trait for objects which can be converted or resolved to one or more
SocketAddr
values.
This trait is used for generic address resolution when constructing network objects. By default it is implemented for the following types:
-
SocketAddr
:to_socket_addrs
is the identity function. -
SocketAddrV4
,SocketAddrV6
,(IpAddr, u16)
,(Ipv4Addr, u16)
,(Ipv6Addr, u16)
:to_socket_addrs
constructs aSocketAddr
trivially. -
(&str, u16)
:&str
should be either a string representation of anIpAddr
address as expected byFromStr
implementation or a host name.u16
is the port number. -
&str
: the string should be either a string representation of aSocketAddr
as expected by itsFromStr
implementation or a string like<host_name>:<port>
pair where<port>
is au16
value.
This trait allows constructing network objects like TcpStream
or
UdpSocket
easily with values of various types for the bind/connection
address. It is needed because sometimes one type is more appropriate than
the other: for simple uses a string like "localhost:12345"
is much nicer
than manual construction of the corresponding SocketAddr
, but sometimes
SocketAddr
value is the main source of the address, and converting it to
some other type (e.g., a string) just for it to be converted back to
SocketAddr
in constructor methods is pointless.
Addresses returned by the operating system that are not IP addresses are silently ignored.
§Examples
Creating a SocketAddr
iterator that yields one item:
use std::net::{ToSocketAddrs, SocketAddr};
let addr = SocketAddr::from(([127, 0, 0, 1], 443));
let mut addrs_iter = addr.to_socket_addrs().unwrap();
assert_eq!(Some(addr), addrs_iter.next());
assert!(addrs_iter.next().is_none());
RunCreating a SocketAddr
iterator from a hostname:
use std::net::{SocketAddr, ToSocketAddrs};
// assuming 'localhost' resolves to 127.0.0.1
let mut addrs_iter = "localhost:443".to_socket_addrs().unwrap();
assert_eq!(addrs_iter.next(), Some(SocketAddr::from(([127, 0, 0, 1], 443))));
assert!(addrs_iter.next().is_none());
// assuming 'foo' does not resolve
assert!("foo:443".to_socket_addrs().is_err());
RunCreating a SocketAddr
iterator that yields multiple items:
use std::net::{SocketAddr, ToSocketAddrs};
let addr1 = SocketAddr::from(([0, 0, 0, 0], 80));
let addr2 = SocketAddr::from(([127, 0, 0, 1], 443));
let addrs = vec![addr1, addr2];
let mut addrs_iter = (&addrs[..]).to_socket_addrs().unwrap();
assert_eq!(Some(addr1), addrs_iter.next());
assert_eq!(Some(addr2), addrs_iter.next());
assert!(addrs_iter.next().is_none());
RunAttempting to create a SocketAddr
iterator from an improperly formatted
socket address &str
(missing the port):
use std::io;
use std::net::ToSocketAddrs;
let err = "127.0.0.1".to_socket_addrs().unwrap_err();
assert_eq!(err.kind(), io::ErrorKind::InvalidInput);
RunTcpStream::connect
is an example of an function that utilizes
ToSocketAddrs
as a trait bound on its parameter in order to accept
different types:
use std::net::{TcpStream, Ipv4Addr};
let stream = TcpStream::connect(("127.0.0.1", 443));
// or
let stream = TcpStream::connect("127.0.0.1:443");
// or
let stream = TcpStream::connect((Ipv4Addr::new(127, 0, 0, 1), 443));
RunRequired Associated Types§
sourcetype Iter: Iterator<Item = SocketAddr>
type Iter: Iterator<Item = SocketAddr>
Returned iterator over socket addresses which this type may correspond to.
Required Methods§
sourcefn to_socket_addrs(&self) -> Result<Self::Iter>
fn to_socket_addrs(&self) -> Result<Self::Iter>
Converts this object to an iterator of resolved SocketAddr
s.
The returned iterator might not actually yield any values depending on the outcome of any resolution performed.
Note that this function may block the current thread while resolution is performed.