How to get the Span<Byte> to the HTTP request header in Kestrel

Question

.NET Core now has the efficient Span<T> and related types that allow more efficient memory operations. Also, there are some basic parsing primitives for dealing with Span<Byte> without having to decode UTF-8.

Kestrel can process requests without using string I reckon.

The user of ASP.NET Core, however, gets the request header (request path and HTTP headers) only as strings.

Is there a way to get that as Span<Byte> also? I have a very low-level application where ideally I would want certain requests make no memory allocations. I'm also just curious.

Answer 1

Not at this level, the abstraction for headers is a IHeaderDictionary. Those are parsed before your code runs and we give you a StringValues. There's been various discussions around exposing it as byte[]/Span<byte> but nothing has come of this as yet.