CODEWITHSUNDEEP
ajaxjsonasp.net-mvc-5signalrsignalr-hub
bingecoder
bingecoder

Reputation: 141

SIGNALR: $.connection.hub.start() results in "Error parsing negotiate response."

I had basic SignalR functionality implemented and working in my MVC5/AngularJS application recently, but after shelfing and unshelfing the changes I am now getting an error when the connection is negotiated in $.connection.hub.start().

I've stripped down the code to the very basics, but still get this error. Poking around in the jquery.signalR-2.2.0.js where the negotiate request is made, I found that the result returned from the ajax request to http://localhost:44379/signalr/negotiate?clientProtocol=1.5&connectionData=[] is returning the HTML of the page instead of JSON data!

            connection._.negotiateRequest =  /* This is on line 659 */ signalR.transports._logic.ajax(connection, {
                url: url, // http://localhost:44379/signalr/negotiate?clientProtocol=1.5&connectionData=%5B%5D
                error: function (error, statusText) {
                    // Irrelevant code removed.
                },
                success: function (result) { // We get here at least...
                    var res,
                        keepAliveData,
                        protocolError,
                        transports = [],
                        supportedTransports = [];

                    try {
                        res = connection._parseResponse(result); // This fails because result contains HTML.
                    } catch (error) { 
                        // error.message is "Unexpected token <"
onFailed(signalR._.error(resources.errorParsingNegotiateResponse, error), connection);
                        return;
                    }

Here is my javascript for establishing the hub/connection:

$(function () {

  var hub = $.connection.testHub;

  if (hub)
    console.log("SignalR hub initialized.");

  $.connection.hub.start().done(function () {

    console.log("SignalR connection established.");

  }).fail(function (err) {
    console.log("Error starting SignalR connection: " + err); // Ends up here.
  });

});

And the script references (I have the signalr code in a separate js file named messaging.js):

  <script src="~/assets/js/signalr/jquery.signalR-2.2.0.js"></script>
  <script src="~/Scripts/messaging/messaging.js"></script>
  <script src="~/signalr/hubs"></script>

I don't really understand why the ajax response from signalr/negotiate would be returning HTML instead of JSON. I've stripped down the server side hub code to an empty class with [AllowAnonymous] to ensure nothing in there was causing the problem. I have the app.MapSignalR() call in Startup.cs in place. My first thought, since this occurred after shelfing and unshelfing, was that something didn't make it into the shelf and was lost, but I can't seem to find anything missing...

Anyone have any ideas?

Upvotes: 2

Views: 2676

Answers (1)

bingecoder
bingecoder

Reputation: 141

I found the problem while playing with the rules in web.config. Previously, I had this rule for signalr:

<add input="{REQUEST_URI}" matchType="Pattern" pattern="/signalr/hubs" negate="true" />

Changing the pattern allowed communication with /signalr/negotiate, I think:

<add input="{REQUEST_URI}"      matchType="Pattern"     pattern="^/(signalr)"   negate="true"/>

...I have no idea how this worked before.

Upvotes: 1

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