http: server: Add function to send a chunk of data

[jukkar]

The http_response_send_data() can be used to send a chunk of data
to the peer.

Signed-off-by: Jukka Rissanen [email protected]

[jukkar]

The motivation for this PR is that I needed to use this kind of functionality in #980

[pfalcon]

I'm surprised there was no such function from the beginning - it's natural to generate HTTP response incrementally. Especially due to lack of MTU handling in send, so sending any sizable content will fail (https://jira.zephyrproject.org/browse/ZEP-1998).

However, this patch is a workaround at best. Normal workflow (IMHO) should be: 1) a function to send out headers; 2) a function to send next block of data, taking its length.

This patch stuffs both headers and data sending into one function, and expects ASCII string only. Weird.

I approve, because it's move in the right direction (but very slow ;-) ).

[jukkar]

However, this patch is a workaround at best. Normal workflow (IMHO) should be: 1) a function to send out headers; 2) a function to send next block of data, taking its length.

I agree, we need to rework the HTTP APIs.