The function stream_socket_recvfrom() accepts data from a remote socket up to length bytes. If address is provided it will be populated with the address of the remote socket.
The value of flags can be any combination of the following:
/* Open a server socket to port 1234 on localhost */
$server = stream_socket_server('tcp://127.0.0.1:1234');
/* Accept a connection */
$socket = stream_socket_accept($server);
/* Grab a packet (1500 is a typical MTU size) of OOB data */
echo "Received Out-Of-Band: '" . stream_socket_recvfrom($socket, 1500, STREAM_OOB) . "'\n";
/* Take a peek at the normal in-band data, but don't comsume it. */
echo "Data: '" . stream_socket_recvfrom($socket, 1500, STREAM_PEEK) . "'\n";
/* Get the exact same packet again, but remove it from the buffer this time. */
echo "Data: '" . stream_socket_recvfrom($socket, 1500) . "'\n";
/* Close it up */
If a message received is longer than the length parameter, excess bytes may be discarded depending on the type of socket the message is received from (such as UDP).
Calls to stream_socket_recvfrom() on socket-based streams, after calls to buffer-based stream functions (like fread() or stream_get_line()) read data directly from the socket and bypass the stream buffer.