IErrorHandler returning wrong message body when HTTP status code is 401 Unauthorized

Question

I have implemented IErrorHandler to handle authorization exceptions thrown within the constructor of my restful WCF service. When a general exception is caught my custom typ

Answer 1

After struggling with this for almost a full day I discovered that this was caused by an IIS setting.

Under my API project in IIS, under the Authentication menu I had 'Forms Authentication' set to 'Enabled'. I turned off this 'feature' and the code above started working as expected. I found that this was due to another developer on my team putting code within the web.config file that altered the settings in IIS. Specifically:

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Further, I was able to get the Content-Type header to appear correctly by using the ContentType Property on the WebOperationContext OutgoingResponse object.

// Get the outgoing response portion of the current context
var response = WebOperationContext.Current.OutgoingResponse;

// Add ContentType header that specifies we are using JSON
response.ContentType = new MediaTypeHeaderValue("application/json").ToString();