Consider making header names case insensitive about pistache

[oktal]

Hello,

You are completely right. Currently, headers are stored in a std::unordered_map for constant-time access, which makes case-insensitive access a little bit tricky (we would need to define our own case-insensitive std::hash, or insert lower-case header names into the map).

I think I'll consider switching from std::unordered_map to std::vector or even SmallVector. Lookup will be linear this time but I do not really expect requests to have that much headers. Case-insensitive lookup should then be trivial

[cyremur]

I would probably just transform all header lookup requests into lower-case and only insert lower-case header names into whatever data structure you choose to utilize. The case insensitive hash sounds like a somewhat complicated approach and you won't enforce that there is only one version of the case-insensitive string in the data structure.

[nelsonhf]

I think this should be a mandatory change, because, according to IETF RFC 7230, section 3.2 (Header Fields):

Each header field consists of a case-insensitive field name followed
by a colon (":"), optional leading whitespace, the field value, and
optional trailing whitespace

I have a similar problem with Postman (a simple HTTP client) sending "content-length" instead of "Content-Length".

[xoac]

Should be closed? 54a3731