socket_getpeername()

(PHP 4 >= 4.1.0, PHP 5, PHP 7)

Queries the remote side of the given socket which may either result in host/port or in a Unix filesystem path, dependent on its type

说明

socket_getpeername(resource $socket,string &$address[,int &$port]): bool

Queries the remote side of the given socket which may either result in host/port or in a Unix filesystem path, dependent on its type.

参数

$socket

A valid socket resource created with socket_create() or socket_accept().

$address

If the given socket is of type AF_INET or AF_INET6,socket_getpeername() will return the peers(remote)IP addressin appropriate notation(e.g.127.0.0.1orfe80::1)in the$addressparameter and, if the optional$portparameter is present, also the associated port.

If the given socket is of type AF_UNIX,socket_getpeername() will return the Unix filesystem path(e.g./var/run/daemon.sock)in the$addressparameter.

$port

If given, this will hold the port associated to$address.

返回值

成功时返回TRUE，或者在失败时返回FALSE。socket_getpeername() may also return FALSE if the socket type is not any of AF_INET,AF_INET6, or AF_UNIX, in which case the last socket error code isnotupdated.

注释

Note:
socket_getpeername() should not be used with AF_UNIX sockets created with socket_accept(). Only sockets created with socket_connect() or a primary server socket following a call to socket_bind() will return meaningful values.

Note:
For having socket_getpeername() to return a meaningful value, the socket it is applied upon must of course be one for which the concept of "peer" makes sense.

参见

socket_getsockname()Queries the local side of the given socket which may either result in host/port or in a Unix filesystem path, dependent on its type
socket_last_error()Returns the last error on the socket
socket_strerror()Return a string describing a socket error

socket_getpeername will not work for UDP sockets. Instead, use socket_recvfrom - it provides the IP address and port of the source server - eg:
$size=socket_recvfrom($socket,$input,65535,0,$ipaddress,$port);
echo "Received [$input] ($size bytes) from IP $ipaddress Port $port\n";

The reason it won't work for UDP is that UDP is stateless; logically there are no peers other than at the time a packet is sent or received. Or more strictly, a UDP socket can interact with 0..N peers.