SignalR, camel case and a lost of connection problem

The Problem

Today I went into a problem trying to configure SignalR to automatically serialize my data contracts in camel cases. Having done that once for Web API, I knew that it can be done easily by changing the contract resolver of JSON.NET to CamelCasePropertyNamesContractResolver. So I went ahead and incorporate the new ContractResolver to SignalR:

It looks good and everything run without a warning or error except that SignalR is no longer be able to connect to the server. I confirmed this by putting a breakpoint inside this function.

At first I did not realize the culprit was the camel case, so I try to dig deeper under the hood. I used the new diagnostic tool of IE11 to see what’s going on and compared with a previous version to see what’s going on. I could clearly see that the new version lack the 2 calls: connect and send although the negotiate when through successfully with a 200 response. (The first image was the SignalR calls in the new version and the second image was the SignalR calls in the old version)

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I decided to dig even deeper into the negotiate response, and I found the culprit. The property names here suppose to be proper case, not camel (so it should be Url instead of url). So probably SignalR cannot interpret the response!

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The solution

This problem was actually solved properly by several people.

http://msmvps.com/blogs/theproblemsolver/archive/2013/03/14/signalr-and-camelcase-data-contracts.aspx

http://blogs.msdn.com/b/stuartleeks/archive/2012/09/10/automatic-camel-casing-of-properties-with-signalr-hubs.aspx

The basic idea was to change the contract resolver but limit the effect of camel case to only classes external to SignalR. I tried the solution in the first link and it worked like a charm! It’s great to learn that today!

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