This implements the upcoming draft-13
but has bits to make it work with draft-02
that most (all?) Chromium versions use.
Data and events are not going through
cowboy_stream beyond init. Since this
approach appears to work well it may
be a good idea to do the same for
Websocket over HTTP/2+ and improve
its performance.
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.
This commit reworks the logging that Cowboy does via
error_logger to make the module that will do the actual
logging configurable.
The logger module interface must be the same as logger
and lager: a separate function per log level with the
same log levels they support.
The default behavior remains to call error_logger,
although some messages were downgraded to warnings
instead of errors. Since error_logger only supports
three different log levels, some messages may get
downgraded/upgraded depending on what the original
log level was to make them compatible with error_logger.
The {log, Level, Format, Args} command was also
added to stream handlers. Stream handlers should
use this command to log messages because it allows
writing a stream handler to intercept some of those
messages and extract information or block them as
necessary.
The logger option only applies to Cowboy itself,
not to the messages Ranch logs, so more work remains
to be done in that area.
This callback is called when an error occurs before the request
(including headers, excluding body) was fully received. The
init/3 callback will not be called. The callback receives the
partial Req object (possibly empty), the reason for the error
and the response command that the server will send. It allows
you to be aware of the error and possibly modify the response
before it is sent.
The stream handlers can be specified using the protocol
option 'stream_handlers'. It defaults to [cowboy_stream_h].
The cowboy_stream_h module currently does not forward the
calls to further stream handlers. It feels like an edge
case; usually we'd want to put our own handlers between
the protocol code and the request process. I am therefore
going to focus on other things for now.
The various types and specifications for stream handlers
have been updated and the cowboy_stream module can now
be safely used as a behavior. The interface might change
a little more, though.
This commit does not include tests or documentation.
They will follow separately.
This commit is not only an early preview of HTTP/2, it is an
early preview of the new Cowboy architecture that will be
presented tomorrow in my talk. If you have found it before
the talk, great! It's not complete so you better go watch
the talk anyway.
