Is “Content-Length” or “chunked transfer-encoding” a must for Http request?

Question

Could someone tell me about that Content-Length or Transfer-Encoding: \"Chunked\" is a must for Http request ? I\'m using c++ to write a http sever.

The http respond

Answer 1

If you don't specify a Transfer-Encoding or Content-Length then the request (or response) is implicitly a variable length request/response and the only way to signal the end of the body is to shutdown the connection (and conversely detect the shutdown/eof in the receiver).

This means that this kind of request/response is also implicitly Connection: close

If you're implementing HTTP1.1 then you must support all three transfer methods.

When I wrote my HTTP server I abstracted the concept of a "request stream" from the concept of a "connection stream". The "request stream" is polymorphic and supports the concept of reading to "EOF". There's no reason you couldn't also have a method on there to "read_chunk". In the case of a non-chunked request, this could simply read until EOF.

This allowed me to implement simultaneous execution of multiple requests on the same connection (but there is some jiggery-pokery to ensure that the responses go back in the correct order!)