Hi Ernie,
Quick response as I'm just going to bed.

Subscribing is fine from a browser so if say you are connecting to a broker you can happily do a receive with an address like say localhost or whatever, but a browser can't really act as a "server" - you are clearly trying to get your browser to do a socket listen (using the address of the form amqp://~0.0.0.0 )


That's just a typical browser security limitation I'm afraid and something in browser WebSockets don't support.

It's not a defect, just a limitation.

Now technically it's something that just might be possible with WebRTC, as it happens emscripten supports a WebRTC transport too, but I've not tried it myself (on my TODO list) but the bottom line is yeah you're mileage is going to be limited by the art of what's actually possible in a browser, but as I've mentioned previously the Java Broker supports WebSocket natively, I've supplied a fairly trivially simple node.js based WebSocket<->TCP Socket proxy and also you can fairly easily stand up a node based proton intermediary so not having browser peer to browser peer is probably not a huge issue (though proving AMQP over WebRTC would be pretty cool and as I say it *should* work I've just not got round to trying it).

HTH
Frase


On 04/09/14 21:43, Ernest Allen wrote:
I'm getting an error when trying to receive messages from within a browser. The same code 
runs fine when run from the command line using "node".

The error message is:
Module.MessengerError {name: "MessengerError", message: "listen: Not 
supported", constructor: function, toString: function}
The error happens when calling messenger.subscribe(address);

Is it the case that subscribing is actually not supported from within a 
browser, or am I possibly doing something wrong?

I basically just took the code from recv.js and put it in a HTML page.

Here is the code:
<!DOCTYPE html> <!-- HTML5 doctype -->
<html>
<head>
        <title>Simple Proton Messenger Send Example</title>
        <meta http-equiv="content-type" content="text/html;charset=utf-8" />

<script type="text/javascript" 
src="../../../node_modules/qpid-proton/lib/proton.js"></script>

<script type="text/javascript">

var address = "amqp://~0.0.0.0";
var message = new proton.Message();
var messenger = new proton.Messenger();

var pumpData = function() {
     while (messenger.incoming()) {
         var t = messenger.get(message);

         console.log("Address: " + message.getAddress());
         console.log("Subject: " + message.getSubject());

         // body is the body as a native JavaScript Object, useful for most 
real cases.
         //console.log("Content: " + message.body);

         // data is the body as a proton.Data Object, used in this case because
         // format() returns exactly the same representation as recv.c
         console.log("Content: " + message.data.format());

         messenger.accept(t);
     }
};

console.log("address = '" + address + "'");
messenger.setIncomingWindow(1024);

messenger.on('error', function(error) {console.log(error);});
messenger.on('work', pumpData);
messenger.start();

messenger.subscribe(address);
messenger.recv(); // Receive as many messages as messenger can buffer.


</script>

</head>

<body>
</body>

</html>


Regards,
-Ernie


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