Adding HttpClient headers generates a FormatException with some values

Question

This occurred within the context of coding against Google Cloud Messaging, but applies elsewhere.

Consider the following:

var http = new HttpClient();
http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("key=XXX");

and

var http = new HttpClient();
http.DefaultRequestHeaders.Add("Authorization", "key=XXX");

both of which generate a FormatException:

System.FormatException : The format of value key=XXX' is invalid.

The solution is to remove the equals sign.

1. Digging into reflector shows there is oodles of validation and parsing code that runs when adding a a new header value. Why is all this necessary? Shouldn't this client just be getting out of our way?

2. How do you escape the equals sign so that adding this value succeeds?

Answer 1

Not sure if still relevant, but I recently ran into this same issue and was able to solve it by calling a different method to add the header information:

var http = new HttpClient();
http.DefaultRequestHeaders.TryAddWithoutValidation("Authorization", "key=XXX");