Fix: Ignore read-only headers in DedupeResponseHeaderGatewayFilterFactory

[alex-cova]

This pull request includes one change to the DedupeResponseHeaderGatewayFilterFactory class which now ignores the headers if they are read-only.

Reason:

If the headers are read-only, the dedupe method throws UnsupportedOperationException

Solve:

If the headers are read-only, ignore it.

if (headers.getClass().getName().equals("org.springframework.http.ReadOnlyHttpHeaders")) {
    return;
}

A try-catch block may be more suitable...

[spencergibb]

Upcoming versions of framework and boot should fix the read only headers problem, so this shouldn't be needed. And you should compare classes with .class not a string compare.

[alex-cova]

Upcoming versions of framework and boot should fix the read only headers problem, so this shouldn't be needed. And you should compare classes with .class not a string compare.

I Agree but, org.springframework.http.ReadOnlyHttpHeaders is not public, it's package-private

[spencergibb]

Either way, this shouldn't be needed at all