58 lines
2.2 KiB
Erlang
58 lines
2.2 KiB
Erlang
%% Copyright (c) 2011-2024, Loïc Hoguin <essen@ninenines.eu>
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%%
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%% Permission to use, copy, modify, and/or distribute this software for any
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%% purpose with or without fee is hereby granted, provided that the above
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%% copyright notice and this permission notice appear in all copies.
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%%
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%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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%% Handler middleware.
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%%
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%% Execute the handler given by the <em>handler</em> and <em>handler_opts</em>
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%% environment values. The result of this execution is added to the
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%% environment under the <em>result</em> value.
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-module(cowboy_handler).
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-behaviour(cowboy_middleware).
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-export([execute/2]).
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-export([terminate/4]).
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-callback init(Req, any())
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-> {ok | module(), Req, any()}
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| {module(), Req, any(), any()}
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when Req::cowboy_req:req().
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-callback terminate(any(), map(), any()) -> ok.
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-optional_callbacks([terminate/3]).
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-spec execute(Req, Env) -> {ok, Req, Env}
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when Req::cowboy_req:req(), Env::cowboy_middleware:env().
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execute(Req, Env=#{handler := Handler, handler_opts := HandlerOpts}) ->
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try Handler:init(Req, HandlerOpts) of
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{ok, Req2, State} ->
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Result = terminate(normal, Req2, State, Handler),
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{ok, Req2, Env#{result => Result}};
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{Mod, Req2, State} ->
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Mod:upgrade(Req2, Env, Handler, State);
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{Mod, Req2, State, Opts} ->
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Mod:upgrade(Req2, Env, Handler, State, Opts)
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catch Class:Reason:Stacktrace ->
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terminate({crash, Class, Reason}, Req, HandlerOpts, Handler),
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erlang:raise(Class, Reason, Stacktrace)
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end.
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-spec terminate(any(), Req | undefined, any(), module()) -> ok when Req::cowboy_req:req().
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terminate(Reason, Req, State, Handler) ->
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case erlang:function_exported(Handler, terminate, 3) of
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true ->
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Handler:terminate(Reason, Req, State);
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false ->
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ok
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end.
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