SignalR client function not called when transport=serverSentEvents

Question

On my machines I find that SignalR client functions are not called in Chrome.

My SignalR test app works fine with with IE9, Firefox and even Safari on my iphone. Looking at Fiddler, these browsers all seem to negotiate transport=longPolling. But Chrome negotiates a connection with transport=serverSentEvents, and I'm assuming this is why client functions are not called in Chrome.

More detail: I'm using full IIS (not IIS express) on Windows 7. I'm using SignalR version 1.0.0-rc2. I've disabled my AVG firewall and the Windows firewall is not running. Chrome is version 24.0.1312.56, and was up-to-date at the time of writing. The app is invoked on localhost.

On Chrome, the signalR connection seems to take place OK - the $.connection.hub.start().done callback function is invoked. But after that, the client function is never called, even while the other browsers work just fine.

In the client-side code, I've turned on logging with

$.connection.hub.logging = true;

I can see log messages in Chrome's javascript console that correspond to a successful connection. For reference, those log messages are

[20:22:16 GMT+0800 (W. Australia Standard Time)] SignalR: Negotiating with '/SignalRChat-RC/signalr/negotiate'. jquery.signalR-1.0.0-rc2.js:54
[20:22:16 GMT+0800 (W. Australia Standard Time)] SignalR: Attempting to connect to SSE endpoint 'http://localhost/SignalRChat-RC/signalr/connect?transport=serverSentEvents&…7-22c5dbf27e0d&connectionData=%5B%7B%22name%22%3A%22chathub%22%7D%5D&tid=3' jquery.signalR-1.0.0-rc2.js:54
[20:22:16 GMT+0800 (W. Australia Standard Time)] SignalR: EventSource connected jquery.signalR-1.0.0-rc2.js:54
[20:22:16 GMT+0800 (W. Australia Standard Time)] SignalR: Now monitoring keep alive with a warning timeout of 40000 and a connection lost timeout of 60000 jquery.signalR-1.0.0-rc2.js:54

But there are no messages logged in Chrome's javascript console when a client-side method is invoked.

Interestingly, the send method works OK on Chrome. The other clients display a message sent from Chrome even through Chrome itself can't see it. The application is pretty much the chat application from the signalR tutorial at http://www.asp.net/signalr/overview/getting-started/tutorial-getting-started-with-signalr

If I explicitly specify longPolling in the start method, i.e.

$.connection.hub.start({ transport: 'longPolling' })

then Chrome works OK. But my expectation was that I should be able to allow the browsers to negotiate their connection, and things would Just Work.

For reference, the relevant part of my client-side code looks like this:

$(function () {
    // Turn on logging to the javascript console
    $.connection.hub.logging = true;

    // set up an error-handling function
    $.connection.hub.error(function (err) {
        alert("Error signalR:" + JSON.stringify(err));
    });

    // Declare a proxy to reference the hub.  
    var chat = $.connection.chatHub;

    // Create a function that the hub can call to broadcast messages.
    // This function is never called when running in Chrome with the default signalR connection
    chat.client.broadcastMessage = function (name, message) {
        // Html encode display name and message.  
        var encodedName = $('<div />').text(name).html();
        var encodedMsg = $('<div />').text(message).html();
        // Add the message to the page.  
        $('#discussion').append('<li><strong>' + encodedName
            + '</strong>:&nbsp;&nbsp;' + encodedMsg + '</li>');
    };

    // Get the user name and store it to prepend to messages. 
    $('#displayname').val(prompt('Enter your name:', ''));
    // Set initial focus to message input box.   
    $('#message').focus();

    // Start the connection. 
    // Use $.connection.hub.start({ transport: 'longPolling' }) for reliability
    // Use $.connection.hub.start() to demonstrate that Chrome doesn't receive messages
    $.connection.hub.start().done(function () {
        // Enable the "Send" button
        $('#sendmessage').removeAttr('disabled');
        $('#sendmessage').click(function () {
            // Call the Send method on the hub.  
            chat.server.send($('#displayname').val(), $('#message').val());
            // Clear text box and reset focus for next comment.  
            $('#message').val('').focus();
        });
    });
});

Can anybody see what I'm doing wrong?

Answer 1

I tried the sample in Win7 Google Chrome 24 and it works fine.

You can troubleshoot installing Fiddler and setting breakpoints in the javascript

POST /signalr/send?transport=serverSentEvents&connectionId=6ff0bffa-c31e-4d85-9aff-24f4528555ee HTTP/1.1
Host: localhost:43637
Connection: keep-alive
Content-Length: 113
Accept: application/json, text/javascript, */*; q=0.01
Origin: 
X-Requested-With: XMLHttpRequest
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.57 Safari/537.17
Content-Type: application/x-www-form-urlencoded
Referer: /index.html
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3

data=%7B%22H%22%3A%22chathub%22%2C%22M%22%3A%22Send%22%2C%22A%22%3A%5B%22gus%22%2C%22hello%22%5D%2C%22I%22%3A0%7D