-module(swidden_api_handler). -export([init/2, terminate/3]). -include("swidden.hrl"). %% > re:run(<<"XYZ_20001210.CreateUser">>, <<"^([a-zA-Z]+)\_(\\d{4}\\d{2}\\d{2})\.([a-zA-Z]+)$">>, [{capture, all_but_first, binary}]). %% {match,[<<"XYZ">>,<<"20001210">>,<<"CreateUser">>]} -define(REGEXP, <<"^([a-zA-Z]+)\_(\\d{4}\\d{2}\\d{2})\.([a-zA-Z]+)$">>). -define(DEFAULT_HEADERS, #{<<"content-type">> => <<"application/json">>}). -define(REDIRECT_STATUS_CODE, 307). %% Cowboy read_body/2 の length オプションのデフォルト（1 回あたりの chunk サイズ） -define(READ_BODY_CHUNK_SIZE, 8000000). %% リクエスト Body 全体の上限（Cowboy は chunk 単位の length しか持たないため自前で enforce する） -define(MAX_BODY_SIZE, 8000000). -type state() :: cowboy_handler:opts(). -spec init(cowboy_req:req(), state()) -> {ok, cowboy_req:req(), state()}. init(Req, Opts) -> HeaderName = proplists:get_value(header_name, Opts), Services = proplists:get_value(services, Opts), Interceptor = proplists:get_value(interceptor, Opts), case cowboy_req:method(Req) of <<"POST">> -> case cowboy_req:header(HeaderName, Req) of undefined -> %% ヘッダーがみつからない RawJSON = jsone:encode(#{type => <<"MissingHeaderName">>}, [skip_undefined]), Req2 = cowboy_req:reply(400, ?DEFAULT_HEADERS, RawJSON, Req), {ok, Req2, Opts}; HeaderValue -> %% Service_Version.Operation として分解する case re:run(HeaderValue, ?REGEXP, [{capture, all_but_first, binary}]) of {match, [Service, Version, Operation]} -> case lists:member(Service, Services) of true -> Req2 = handle(Service, Version, Operation, Req, Interceptor), {ok, Req2, Opts}; false when Services == [] -> Req2 = handle(Service, Version, Operation, Req, Interceptor), {ok, Req2, Opts}; false -> Req2 = cowboy_req:reply(400, ?DEFAULT_HEADERS, jsone:encode(#{error_type => <<"InvalidTarget">>}, [skip_undefined]), Req), {ok, Req2, Opts} end; _ -> %% サービスに対応してなかったよ Req2 = cowboy_req:reply(400, ?DEFAULT_HEADERS, jsone:encode(#{error_type => <<"MissingService">>}, [skip_undefined]), Req), {ok, Req2, Opts} end end; _Other -> %% POST 以外受け付けていないのでエラーメッセージ RawJSON = jsone:encode(#{type => <<"UnexpectedMethod">>}, [skip_undefined]), Req2 = cowboy_req:reply(400, ?DEFAULT_HEADERS, RawJSON, Req), {ok, Req2, Opts} end. read_body(Req) -> read_body(Req, <<>>, 0). read_body(Req, Acc, AccSize) -> case AccSize >= ?MAX_BODY_SIZE of true -> {error, payload_too_large}; false -> %% length は chunk サイズ（best effort）。各 read_body 呼び出しごとに渡す。 ChunkSize = erlang:min(?READ_BODY_CHUNK_SIZE, ?MAX_BODY_SIZE - AccSize), try cowboy_req:read_body(Req, #{length => ChunkSize}) of {ok, Data, Req2} -> %% fin 時は chunk サイズを超える Body が届く（cowboy_stream_h の IsFin =:= fin 分岐） NewSize = AccSize + byte_size(Data), case NewSize > ?MAX_BODY_SIZE of true -> {error, payload_too_large}; false -> {ok, iolist_to_binary([Acc, Data]), Req2} end; {more, Data, Req2} -> DataSize = byte_size(Data), NewSize = AccSize + DataSize, %% {more, ...} は nofin: これ以上 Body が続く。 %% read_urlencoded_body/2 と同様、chunk が満杯なら上限超過とみなす。 case (NewSize > ?MAX_BODY_SIZE) orelse (DataSize >= ChunkSize) of true -> {error, payload_too_large}; false -> read_body(Req2, [Acc, Data], NewSize) end catch exit:timeout -> {error, timeout}; exit:{{request_error, payload_too_large, _}, _} -> {error, payload_too_large} end end. handle(Service, Version, Operation, Req, Interceptor) -> %% TODO(v); リファクタリング case cowboy_req:has_body(Req) of true -> case read_body(Req) of {error, payload_too_large} -> reply_json(413, #{error_type => <<"PayloadTooLarge">>}, Req); {error, timeout} -> reply_json(408, #{error_type => <<"RequestTimeout">>}, Req); {ok, <<>>, Req2} -> case dispatch(Service, Version, Operation, Interceptor) of 200 -> cowboy_req:reply(200, ?DEFAULT_HEADERS, [], Req2); {?REDIRECT_STATUS_CODE, Location} -> cowboy_req:reply(?REDIRECT_STATUS_CODE, #{<<"location">> => Location}, [], Req2); {StatusCode, JSON} -> RawJSON = jsone:encode(JSON, [skip_undefined]), cowboy_req:reply(StatusCode, ?DEFAULT_HEADERS, RawJSON, Req2) end; {ok, Body, Req2} -> case validate_json(Service, Version, Operation, Body, Interceptor) of 200 -> cowboy_req:reply(200, ?DEFAULT_HEADERS, [], Req2); {?REDIRECT_STATUS_CODE, Location} -> cowboy_req:reply(?REDIRECT_STATUS_CODE, #{<<"location">> => Location}, [], Req2); {StatusCode, JSON} -> RawJSON = jsone:encode(JSON, [skip_undefined]), cowboy_req:reply(StatusCode, ?DEFAULT_HEADERS, RawJSON, Req2) end end; false -> case dispatch(Service, Version, Operation, Interceptor) of 200 -> cowboy_req:reply(200, ?DEFAULT_HEADERS, [], Req); {?REDIRECT_STATUS_CODE, Location} -> cowboy_req:reply(?REDIRECT_STATUS_CODE, #{<<"location">> => Location}, [], Req); {StatusCode, JSON} -> RawJSON = jsone:encode(JSON, [skip_undefined]), cowboy_req:reply(StatusCode, ?DEFAULT_HEADERS, RawJSON, Req) end end. -spec terminate(term(), cowboy_req:req(), state()) -> ok. terminate(normal, _Req, _State) -> ok; terminate(_Reason, _Req, _State) -> ok. dispatch(Service, Version, Operation, Interceptor) -> case swidden_dispatch:lookup(Service, Version, Operation) of not_found -> {400, #{error_type => <<"MissingTarget">>}}; {Module, Function} -> case code:which(Module) of non_existing -> {400, #{error_type => <<"MissingTargetModule">>}}; _ -> case lists:member({Function, 0}, Module:module_info(exports)) of true -> preprocess0(Module, Function, Interceptor); false -> {400, #{ error_type => <<"MissingTargetFunction">>, error_reason => #{ service => Service, version => Version, operation => Operation } }} end end end. validate_json(Service, Version, Operation, RawJSON, Interceptor) -> case swidden_json_schema:validate_json(Service, Version, Operation, RawJSON) of {ok, Module, Function, JSON} -> case code:which(Module) of non_existing -> {400, #{error_type => <<"MissingTargetModule">>}}; _ -> case lists:member({Function, 1}, Module:module_info(exports)) of true -> preprocess1(Module, Function, JSON, Interceptor); false -> {400, #{ error_type => <<"MissingTargetFunction">>, error_reason => #{ service => Service, version => Version, operation => Operation } }} end end; {error, {data_error, _Reason}} -> {400, #{error_type => <<"MalformedJSON">>}}; {error, {database_error, _Key, schema_not_found}} -> %% TODO(v); この部分は外だしする {400, #{ error_type => <<"SchemaNotFound">>, error_reason => #{ service => Service, version => Version, operation => Operation } }}; {error, Reasons} -> ErrorReasons = swidden_json_schema:to_json(Reasons), {400, #{ error_type => <<"InvalidJSON">>, error_reason => ErrorReasons }} end. preprocess0(Module, Function, undefined) -> apply_mfa(Module, Function, []); preprocess0(Module, Function, Interceptor) -> run_interceptor(fun() -> case Interceptor:preprocess(Module, Function) of continue -> apply_mfa(Module, Function, [], Interceptor); {stop, Result} -> safe_response(Result) end end). preprocess1(Module, Function, JSON, undefined) -> apply_mfa(Module, Function, [JSON]); preprocess1(Module, Function, JSON0, Interceptor) -> run_interceptor(fun() -> case Interceptor:preprocess(Module, Function, JSON0) of {continue, JSON1} -> apply_mfa(Module, Function, [JSON1], Interceptor); {stop, Result} -> postprocess(Module, Function, Result, Interceptor) end end). apply_mfa(Module, Function, Args) -> try Result = apply(Module, Function, Args), response(Result) catch _Class:_Reason:_Stack -> {500, #{error_type => <<"HandlerException">>}} end. apply_mfa(Module, Function, Args, Interceptor) -> try Result = apply(Module, Function, Args), postprocess(Module, Function, Result, Interceptor) catch _Class:_Reason:_Stack -> {500, #{error_type => <<"HandlerException">>}} end. postprocess(Module, Function, Result0, Interceptor) -> run_interceptor(fun() -> Result1 = Interceptor:postprocess(Module, Function, Result0), safe_response(Result1) end). run_interceptor(Fun) -> try Fun() of Result -> Result catch _Class:_Reason:_Stack -> handler_exception() end. safe_response(Result) -> try response(Result) catch _Class:_Reason:_Stack -> handler_exception() end. handler_exception() -> {500, #{error_type => <<"HandlerException">>}}. reply_json(StatusCode, JSON, Req) -> RawJSON = jsone:encode(JSON, [skip_undefined]), cowboy_req:reply(StatusCode, ?DEFAULT_HEADERS, RawJSON, Req). response({ok, {redirect, Location}}) -> {?REDIRECT_STATUS_CODE, Location}; response(ok) -> 200; response({ok, RespJSON}) -> {200, RespJSON}; response({error, Type}) -> {400, #{error_type => Type}}; response({error, Type, Reason}) -> {400, #{error_type => Type, error_reason => Reason}}.