ZMQSocket::recv

(PECL zmq >= 0.5.0)

ZMQSocket::recv — Receives a message

Description

public ZMQSocket::recv(int $mode = 0): string

Receive a message from a socket. By default receiving will block until a message is available unless ZMQ::MODE_DONTWAIT flag is used. ZMQ::SOCKOPT_RCVMORE socket option can be used for receiving multi-part messages. See ZMQSocket::setSockOpt() for more information.

Parameters

mode: Pass mode flags to receive multipart messages or non-blocking operation. See ZMQ::MODE_* constants.

Return Values

Returns the message. If ZMQ::MODE_DONTWAIT is used and the operation would block false shall be returned.

Errors/Exceptions

Throws ZMQSocketException on error.

Examples

Example #1 A send/recv example

Non-blocking send / receive


<?php

/* Create new queue object, there needs to be a server at the other end */
$queue = new ZMQSocket(new ZMQContext(), ZMQ::SOCKET_REQ);
$queue->connect("tcp://127.0.0.1:5555");

/* Assign socket 1 to the queue, send and receive */
$retries = 5;
$sending = true;

/* Start a loop */
do {
    try {
        /* Try to send / receive */
        if ($sending) {
            echo "Sending message\n";
            $queue->send("This is a message", ZMQ::MODE_DONTWAIT);
            $sending = false;
        } else {
            echo "Got response: " . $queue->recv(ZMQ::MODE_DONTWAIT) . "\n";
            break;
        }
    } catch (ZMQSocketException $e) {
        /* EAGAIN means that the operation would have blocked, retry */
        if ($e->getCode() === ZMQ::ERR_EAGAIN) {
            echo " - Got EAGAIN, retrying ($retries)\n";
        } else {
            die(" - Error: " . $e->getMessage());
        }
    }
    /* Sleep a bit between operations */
    usleep(5);
} while (--$retries);
?>

The above example will output something similar to:

Sending message
 - Unable to execute operation, retrying (4)
Got response: This is a message