Case-sensitivity for custom HTTP headers in response

[marcovisserFurore]

Discussed in https://github.com/FirelyTeam/firely-net-sdk/discussions/2107

^{Originally posted by cdaven June 1, 2022} The HTTP specification says that headers are case insensitive (see RFC 2616, section 4.2). .NET parses the basic headers and puts them in the HttpResponseMessage.Headers object, so we don't have to think about this. However, all custom headers are copied to the EntryResponse object by HttpToEntryExtensions.SetHeaders() into a case-sensitive Dictionary.

You can see what I mean in the unit test TestToTypedEntryResponse(), and change this line:

Headers = new Dictionary<string, string>() { { "Test-key", "Test-value" } },

Change e.g. "Test-key" to "test-key", and the test will fail. Is this intended or a bug?

I thought we could make this easy by making EntryResponse.Headers case-insensitive in the constructor:

public EntryResponse()
{
    Headers = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
}

But since Headers is replaced in e.g. ToTypedEntryResponse(), that would have to be refactored as well.

What do you think? The Swedish NLL implementation has suddenly announced that they will start using lowercase headers only.