I'm trying to implement Publish Subscribe using a Proxy with ZeroMQ and PHP as it is described in the guide in Figure 13. The setup is the same as described here: how to implement Pub-Sub Network with a Proxy by using XPUB and XSUB in ZeroMQ(jzmq) 3.xx
subscriber.php
<?php
$context = new ZMQContext();
$sub = new ZMQSocket($context, ZMQ::SOCKET_SUB);
$sub->connect("tcp://127.0.0.1:5000");
$sub->setSockOpt(ZMQ::SOCKOPT_SUBSCRIBE, 'Hello');
$msg = $sub->recv();
echo "got $msg";
publisher.php
<?php
$context = new ZMQContext();
$pub = new ZMQSocket($context, ZMQ::SOCKET_PUB);
$pub->connect("tcp://127.0.0.1:6000");
while (1) {
echo "publishing";
$pub->send("Hello World");
sleep(1);
}
proxy.php
<?php
$context = new ZMQContext();
$frontend = new ZMQSocket($context, ZMQ::SOCKET_XSUB);
$frontend->bind("tcp://127.0.0.1:6000");
$backend = new ZMQSocket($context, ZMQ::SOCKET_XPUB);
$backend->bind("tcp://127.0.0.1:5000");
$device = new ZMQDevice($frontend, $backend);
$device->run();
If I start all three PHP scripts (first proxy, then publisher, then subscriber) no messages arrive at that subscriber.
In order to see if any messages arrive at the proxy at all, I tried to receive the messages manually on the proxy:
while (true) {
if ($frontend->recv(ZMQ::MODE_DONTWAIT)) {
echo "received message from xpub";
}
if ($frontend->recv(ZMQ::MODE_DONTWAIT)) {
echo "received message from xsub";
}
}
There are serveral related questions on Stack Overflow:
- How to implement Pub-Sub Network with a Proxy by using XPUB and XSUB in ZeroMQ(C++)? - I am using the proxy as described in the answer, but I still don't receive any messages. Therefore this question does not apply
- how to implement Pub-Sub Network with a Proxy by using XPUB and XSUB in ZeroMQ(jzmq) 3.xx The person who answered said the problem was that messages from the publisher were not forwarded to the subscriber. However, I don't receive any messages from the publisher at all.
What am I missing?
