rest - Cowboy 多方法处理器

Question

尝试通过 Cowboy 设置 restful API我需要为所有方法使用一个处理程序的主要事情

这里是路由器::

 start(_Type, _Args) ->
    Dispatch = cowboy_router:compile([
        {'_', [
            {"/api", handler, []},
            {"/api/:id", handler, []}
        ]}
    ]),
    {ok, _} = cowboy:start_clear(http, 100, [{port, 8080}], #{
        env => #{dispatch => Dispatch}
    }),
    api_sup:start_link().

这是处理程序代码::

-module(handler).
-export([init/3, handle/2]).

init(_Transport, Req, []) ->
    {ok, Req, undefined}.

handle(Req, Opts) -> 
  case cowboy_req:method(Req) of
    <<"POST">> -> 
      Body = cowboy_req:has_body(Req),
      Request = postMethod(<<"POST">>, Body, Req),
        {ok, Request, Opts};
    <<"GET">> -> 
      #{id := Id} = cowboy_req:match_qs([{id, [], undefined}], Req),
      Request = getMethod(<<"GET">>, Id, Req),
        {ok, Request, Opts};
    <<"PUT">> -> 
      Body = cowboy_req:has_body(Req),
      Request = putMethod(<<"PUT">>, Body, Req),
        {ok, Request, Opts};
    <<"DELETE">> -> 
      #{id := Id} = cowboy_req:match_qs([{id, [], undefined}], Req),
      Request = deleteMethod(<<"DELETE">>, Id, Req),
        {ok, Request, Opts}
  end.

  postMethod(<<"POST">>, _Body, Req) -> 
    cowboy_req:reply(200, #{<<"content-type">> => <<"application/json; charset=utf-8">>}, <<"{\"status\": \"POST\"}">>, Req).
  getMethod(<<"GET">>, _Id, Req) -> 
      cowboy_req:reply(200, #{<<"content-type">> => <<"application/json; charset=utf-8">>}, <<"{\"status\": \"GET\"}">>, Req).
  putMethod(<<"PUT">>, _Body, Req) -> 
      cowboy_req:reply(200, #{<<"content-type">> => <<"application/json; charset=utf-8">>}, <<"{\"status\": \"PUT\"}">>, Req).
  deleteMethod(<<"DELETE">>, _Id, Req) -> 
      cowboy_req:reply(200, #{<<"content-type">> => <<"application/json; charset=utf-8">>}, <<"{\"status\": \"DELETE\"}">>, Req).

我收到错误:牛仔 500 错误

Answer 1

找到了答案。这是工作正常的代码(使用 Cowboy 的主版本)

-module(handler).

-export([init/2]).
-export([content_types_provided/2]).
-export([content_types_accepted/2]).
-export([allowed_methods/2]).
-export([router/2]).

init(Req, Opts) ->
    {cowboy_rest, Req, Opts}.

allowed_methods(Req, State) ->
    {[<<"GET">>, <<"POST">>, <<"PUT">>, <<"DELETE">>], Req, State}.

content_types_provided(Req, State) ->
    {[{<<"application/json">>, router}], Req, State}.

content_types_accepted(Req, State) ->
    {[{<<"application/json">>, router}], Req, State}.

router(Req, Opts) -> 
  case cowboy_req:method(Req) of
    <<"POST">> -> 
        {<<"{\"status\": \"POST\"}">>, Req, State};
    <<"GET">> -> 
      {<<"{\"status\": \"GET\"}">>, Req, State};
    <<"PUT">> -> 
      {<<"{\"status\": \"PUT\"}">>, Req, State};
    <<"DELETE">> -> 
      {<<"{\"status\": \"DELETE\"}">>, Req, State}
  end.