%% Copyright (c) 2013, James Fish %% %% Permission to use, copy, modify, and/or distribute this software for any %% purpose with or without fee is hereby granted, provided that the above %% copyright notice and this permission notice appear in all copies. %% %% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES %% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF %% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR %% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES %% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN %% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF %% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. %% @doc Behaviour for sub protocols. %% %% Only one function needs to be implemented, upgrade/4. %% It receives the Req, the environment, the handler that the request has been %% routed to and the handler's options. It acts exactly the same as a %% middleware, so returns the same values a middleware's execute/2. %% %% Once the sub protocol has processed the request it should add the result %% to the environment. This is done by adding the tuple {result, Value} to the %% environment list. To continue handling requests on the current connection the %% Value should be the atom ok. Any other value will prevent the processing of %% subsequent requests. %% %% upgrade/4 will be called when a handler's init/3 returns %% {upgrade, protocol, Module}, where Module is the module of the sub protocol. -module(cowboy_sub_protocol). -callback upgrade(Req, Env, module(), any()) -> {ok, Req, Env} | {suspend, module(), atom(), [any()]} | {halt, Req} | {error, cowboy:http_status(), Req} when Req::cowboy_req:req(), Env::cowboy_middleware:env().