When calling cowboy_req:reply/4 with a body a crash will occur
resulting in a 500 response. When calling cowboy_req:stream_reply/2,3
and then attempting to send a body a crash will occur.
This should limit the amount of memory that Cowboy is using
when a handler is sending data much faster than the network.
The new max_stream_buffer_size is a soft limit and only has
an effect when the cowboy_stream_h handler is used.
It is now possible to stream one or more sendfile tuples.
A simple example of what can now be done would be for
example to build a tar file on the fly using the sendfile
syscall for sending the files, or to support Range requests
with more than one range with the sendfile syscall.
When using cowboy_compress_h unfortunately we have to read
the file in order to send it. More options will be added
at a later time to make sure users don't read too much
into memory. This is a new feature however so existing
code is not affected.
Also rework cowboy_http's data sending to be flatter.
Sending data of size 0 with the fin flag set resulted in nothing
being sent to the client and still considering the response to
be finished for HTTP/1.1.
For both HTTP/1.1 and HTTP/2, the final chunk of body that is
sent automatically by Cowboy at the end of a response that the
user did not properly terminate was not passing through stream
handlers. This resulted in issues like compression being incorrect.
Some tests still fail under 20.1.3. They are due to recent zlib
changes and should be fixed in a future patch release. Unfortunately
it does not seem to be any 20.1 version that is safe to use for
Cowboy, although some will work better than others.
The Opts value is put last, to be more consistent with the
rest of the cowboy_req module.
Additionally a test handler was fixed which reduced the number
of errors in http_SUITE.
This is a large commit. The cowboy_req interface has largely
changed, and will change a little more. It's possible that
some examples or tests have not been converted to the new
interface yet. The documentation has not yet been updated.
All of this will be fixed in smaller subsequent commits.
Gotta start somewhere...
