The 'shutdown' atom has a specific meaning inside OTP. We are
instead going to use 'stop' which is pretty much the equivalent
of what we actually do. 'shutdown' is now reserved for future
special processes implementation.
This change simplifies a little more the sub protocols mechanism.
Aliases have been removed. The renaming of loop handlers as long
polling handlers has been reverted.
Plain HTTP handlers now simply do their work in the init/2
callback. There is no specific code for them.
Loop handlers now follow the same return value as Websocket,
they use ok to continue and shutdown to stop.
Terminate reasons for all handler types have been documented.
The terminate callback is now appropriately called in all cases
(or should be).
Behaviors for all handler types have been moved in the module
that implement them. This means that cowboy_handler replaces
the cowboy_http_handler behavior, and similarly cowboy_loop
replaces cowboy_loop_handler, cowboy_websocket replaces
cowboy_websocket_handler. Finally cowboy_rest now has the
start of a behavior in it and will have the full list of
optional callbacks defined once Erlang 18.0 gets released.
The guide has been reorganized and should be easier to follow.
This set of changes is the first step to simplify the
writing of handlers, by removing some extraneous
callbacks and making others optional.
init/3 is now init/2, its first argument being removed.
rest_init/2 and rest_terminate/2 have been removed.
websocket_init/3 and websocket_terminate/3 have been removed.
terminate/3 is now optional. It is called regardless of
the type of handler, including rest and websocket.
The return value of init/2 changed. It now returns
{Mod, Req, Opts} with Mod being either one of the four
handler type or a custom module. It can also return extra
timeout and hibernate options.
The signature for sub protocols has changed, they now
receive these extra timeout and hibernate options.
Loop handlers are now implemented in cowboy_long_polling,
and will be renamed throughout the project in a future commit.
Simplify the interface for most cowboy_req functions. They all return
a single value except the four body reading functions. The reply functions
now only return a Req value.
Access functions do not return a Req anymore.
Functions that used to cache results do not have a cache anymore.
The interface for accessing query string and cookies has therefore
been changed.
There are now three query string functions: qs/1 provides access
to the raw query string value; parse_qs/1 returns the query string
as a list of key/values; match_qs/2 returns a map containing the
values requested in the second argument, after applying constraints
and default value.
Similarly, there are two cookie functions: parse_cookies/1 and
match_cookies/2. More match functions will be added in future commits.
None of the functions return an error tuple anymore. It either works
or crashes. Cowboy will attempt to provide an appropriate status code
in the response of crashed handlers.
As a result, the content decode function has its return value changed
to a simple binary, and the body reading functions only return on success.
This is a first step to improve the HTTP status codes returned
by Cowboy on crashes. We will tweak it over time.
Also fixes a small bug where two replies may have been sent
when using loop handlers under rare conditions.
When something went wrong in a handler we used to report errors
and then terminate the process normally. This doesn't work so
well with links which won't detect failure.
Now we still catch the error, but throw another one with more
details on why it happened, including the Req object information
and the stacktrace. Ranch will then print an error message with
all this information.
Because we crash directly, this also means that we will not hog
resources unnecessarily for too long when something bad happens.
The unmasking logic was based on the length of inflated data instead
of the length of the deflated data. This meant data would get corrupted
when we receive a websocket frame split across multiple TCP packets.
We now always send a failure reason (bad protocol, bad encoding, etc.)
unless the closure was initiated by the client and it didn't send a
close code.
We now check that the close frames have a payload that is valid UTF-8,
unless they don't have a payload at all.
We now do not crash the process anymore when bad opcodes are sent, or
when the opcode 0 is sent before fragmentation was initiated.
Overall this makes us closer to full compliance with the RFC.
Good in theory, but implementations may vary. If something stops
working after this commit we might need some tweaks to support
existing clients.
Please try it and give feedback.
It was only used by Safari 5.0.1 and possibly 5.1. Their market share
is dropping as we speak. It was also insecure (disabled in Firefox
for that reason).
This will allow us to make much more efficient and cleaner code for
the rest of the Websocket versions we support (drafts 7 to 17 + RFC),
which are pretty much all versions seen in the wild excluding the
one we're removing here.
It was added to help with response body streaming functions.
But it was a clumsy solution that we discarded in favor of
passing socket and transport to said function. It was also
very odd compared to the rest of the cowboy_req interface.
If you used this function before, worry not, here's its
proper equivalent.
[Socket, Transport] = cowboy_req:get([socket, transport], Req)
Middlewares allow customizing the request processing.
All existing Cowboy project are incompatible with this commit.
You need to change `{dispatch, Dispatch}` in the protocol options
to `{env, [{dispatch, Dispatch}]}` to fix your code.
This commit prevents erlang messages from keeping a websocket connection
alive. Previously, the timer was canceled upon any activity. Now, the
timeout is only canceled when actual data is sent from the client. The
handler_loop_timeout/1 function is called from websocket_data/4 instead
of handler_before_loop/4. It is also called after every successful reply
in handler_call/4.
The purpose of this patch is to make the arguments cowboy passes to
error_logger more consistent. With this patch there's only 3 variations
on the error_logger argument list; a 5 element list, an 8 element list
and a 10 element list. In all cases, the first 3 arguments are the
Module, Function and Arity of the function being called and the
second-to-last argument is always the Request. Additionally, for lists
longer than 5 elements, the last argument is always the stack-trace.
The added consistency of the argument ordering makes it much easier to
write code in lager's error_logger handler to catch these messages and
write a pretty one-liner (while writing the full message to the
crash.log).
We can now reply empty close, ping and pong frames, or close
frames with a payload.
This means that we can send a frame and then close the connection
in a single operation.
If a close packet is sent, the connection is closed immediately,
even if there was frames that remained to be sent. Cowboy will
silently drop any extra frames in the list given as a reply.
In some situations, the underlying socket might become "half-open" in
which case the websocket will stay in a waiting state indefinitely. The
detection of this state requires checking for errors when calling send.
