This should work very similar to normal supervisors,
in particular during the shutdown sequence when the
connection process goes down or switches to Websocket.
Processes that need to enforce the shutdown timeout
will be required to trap exits, just like in a supervisor.
In a vanilla Cowboy, this only matters at connection
shutdown, as Cowboy will otherwise wait for the request
process to be down before stopping the stream.
Tests are currently missing.
Cowboy was encoding the headers then decoding them when initializing
the request. The problem is that the encoding and decoding contexts
are not the same. Now, Cowboy will directly use the headers it
received in the push command for the new request. This is also
more efficient.
I am surprised it worked at all considering the issue.
There are two important changes in this commit.
Constraints are now producing an error tuple. This error tuple
in turn can be provided to a function for formatting a human
readable error message. Both the error tuple and the formatting
code are controlled by and part of the constraint function.
Constraints now also implement the reverse operation.
When constraint functions only validate, the reverse operation
will be the same as the forward operation. When they also do
some conversion then the reverse operation will reverse it.
Since constraints are now performing 3 different operations
(forward, reverse and format_error), they now take the form
of a function accepting two separate arguments. The operation
is the first argument.
In addition, the return value was changed to take the form
of {ok, Value} | {error, Reason}. The value must be returned
as-is if it was not modified.
They are now cowboy:start_clear/3 and cowboy:start_tls/3.
The NumAcceptors argument can be specified via the
num_acceptor transport option. Ranch has been updated
to 1.4.0 to that effect.
This option allows customizing the compacting of the Req object
when using Websocket. By default it will keep most public fields
excluding headers of course, since those can be large.
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.
These tests cover frame sizes. It's mostly edge cases for sure
(ie misbehaving clients and us having to reject them properly).
I had these almost ready for a long time, so I'm glad I can
push them out.
This requires updating Cowlib too (we currently track master).
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.
Before this commit we had an issue where configuring a
Websocket connection was simply not possible without
doing magic, adding callbacks or extra return values.
The init/2 function only allowed setting hibernate
and timeout options.
After this commit, when switching to a different
type of handler you can either return
{module, Req, State}
or
{module, Req, State, Opts}
where Opts is any value (as far as the sub protocol
interface is concerned) and is ultimately checked
by the custom handlers.
A large protocol like Websocket would accept only
a map there, with many different options, while a
small interface like loop handlers would allow
passing hibernate and nothing else.
For Websocket, hibernate must be set from the
websocket_init/1 callback, because init/2 executes
in a separate process.
Sub protocols now have two callbacks: one with the
Opts value, one without.
The loop handler code was largely reworked and
simplified. It does not need to manage a timeout
or read from the socket anymore, it's the job of
the protocol code. A lot of unnecessary stuff was
therefore removed.
Websocket compression must now be enabled from
the handler options instead of per listener. This
means that a project can have two separate Websocket
handlers with different options. Compression is
still disabled by default, and the idle_timeout
value was changed from inifnity to 60000 (60 seconds),
as that's safer and is also a good value for mobile
devices.
If cowboy_static is initialized with `{priv_file, ...}` or `{priv_dir,
...}`, it is now able to read files from Erlang application .ez
archives.
When serving a file from an archive, the #file_info{} comes from the
archive, not the contained file, except for the size and type. The
erl_prim_loader module is used to read the latter's #file_info{} and the
actual file content (ie. sendfile(2) is not used in this case).
The {data, IsFin, Data} uses IsFin to indicate whether this
is the last chunk, while chunked transfer-encoding uses the
length of Data, and ends when it is 0. We must therefore not
send chunks with empty data.
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.
