Since when are they case sensitive? https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/... says otherwise.
It's possible for a server to treat them as case sensitive, but that seems like a bad idea.
It's possible for a server to treat them as case sensitive, but that seems like a bad idea.
HTTP/2, headers are not unique if they only differ by casing, but they must be encoded as lowercase.
Just as in HTTP/1.x, header field names are strings of ASCII characters that are compared in a case-insensitive fashion. However, header field names MUST be converted to lowercase prior to their encoding in HTTP/2. A request or response containing uppercase header field names MUST be treated as malformed (Section 8.1.2.6).[1]
Each header field consists of a name followed by a colon (":") and the field value. Field names are case-insensitive.[2]
[1]: https://datatracker.ietf.org/doc/html/rfc7540#section-8.1.2
[2]: https://datatracker.ietf.org/doc/html/rfc2616#section-4.2
> Since when are they case sensitive?
[...]
When I originally read it hours ago, I also read it as "...HTTP headers are case sensitive," (emphasis mine).
That said, there is one caveat regarding case sensitivity for headers encoded for HTTP/2.