hello_erlang_app.erl

%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
hello_erlang.app.src
%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%

{application, hello_erlang, [
  {description, ""},
  {vsn, "0.1.0"},
  {id, "git"},
  {modules, []},
  {registered, []},
  {applications, [
    kernel,
    stdlib,
    cowboy,
    mongodb,
    jiffy
  ]},
  {mod, {hello_erlang_app, []}},
  {env,
    [
      {
        mongodb_pools,
        [
          {
           mg_pool1,
           [
             {size, 10},
             {max_overflow, 20}
           ],
           [
             {hostname, "127.0.0.1"},
             {database, "user"},
             {username, "zhk"},
             {password, "zhk"}
           ]
          }
        ]
      }
    ]
  }
]}.



%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
db_mongo_handler.erl
%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
%%%-------------------------------------------------------------------
%%% @author zhouhuakang
%%% @copyright (C) 2015, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 27. Jan 2015 10:44 AM
%%%-------------------------------------------------------------------
-module(db_mongo_handler).
-author("zhouhuakang").

-behaviour(gen_server).
%% API
-export([start_link/1]).

%% gen_server callbacks
-export([init/1,
  handle_call/3,
  handle_cast/2,
  handle_info/2,
  terminate/2,
  code_change/3]).



-define(SERVER, ?MODULE).

-record(state, {connection}).

%%%===================================================================
%%% API
%%%===================================================================

%%--------------------------------------------------------------------
%% @doc
%% Starts the server
%%
%% @end
%%--------------------------------------------------------------------
-spec(start_link(Args :: list()) ->
  {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
start_link(Args) ->
  gen_server:start_link(?MODULE, Args, []).


%%%===================================================================
%%% gen_server callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Initializes the server
%%
%% @spec init(Args) -> {ok, State} |
%%                     {ok, State, Timeout} |
%%                     ignore |
%%                     {stop, Reason}
%% @end
%%--------------------------------------------------------------------
-spec(init(Args :: term()) ->
  {ok, State :: #state{}} | {ok, State :: #state{}, timeout() | hibernate} |
  {stop, Reason :: term()} | ignore).
init(Args) ->
  Hostname = proplists:get_value(hostname, Args),
  Database = proplists:get_value(database, Args),
  %% no user and pass for the moment
  Username = proplists:get_value(username, Args),
  Password = proplists:get_value(password, Args),
  {ok, Connection} = mongo:connect(Hostname, 27017, Database),

  io:format("***************************Debug*********************************~n
  Module:~p ~n  Line:~p ~n  Database Connection:~p ~n", [?MODULE, ?LINE, Connection]),
  %% user-specific setup
  SetupFun = proplists:get_value(setup, Args),
  case SetupFun of
    undefined -> ok;
    {Mod, Fun} -> erlang:apply(Mod, Fun, [Connection, Args])
  end,

  {ok, #state{connection = Connection}}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling call messages
%%
%% @end
%%--------------------------------------------------------------------
-spec(handle_call(Request :: term(), From :: {pid(), Tag :: term()},
    State :: #state{}) ->
  {reply, Reply :: term(), NewState :: #state{}} |
  {reply, Reply :: term(), NewState :: #state{}, timeout() | hibernate} |
  {noreply, NewState :: #state{}} |
  {noreply, NewState :: #state{}, timeout() | hibernate} |
  {stop, Reason :: term(), Reply :: term(), NewState :: #state{}} |
  {stop, Reason :: term(), NewState :: #state{}}).


handle_call({get_user, {Collection, Selector}}, _From, #state{connection = Connection} = State) ->
  io:format("***************************Debug*********************************~n
  Module:~p ~n  Line:~p ~n   Handle_call Connection:~p ~n Collection:~p ~n
  Selector:~p ~n Connection is is_pid()? ~p ~n Collection is binary()? ~p ~n",
    [?MODULE, ?LINE, Connection, Collection, Selector, is_pid(Connection), is_binary(Collection)]),
  Cursor = mongo:find(Connection, Collection, Selector ),
  io:format("***************************Debug*********************************~n Module:~p ~n  Line:~p ~n
  Cursor:~p ~n", [?MODULE, ?LINE, Cursor]),
  Result = mc_cursor:rest(Cursor),
  [Head | _] = Result,
  {_, _, _, NameValue, _, AgeValue} = Head,
  io:format("***************************Debug*********************************~n Module:~p ~n  Line:~p ~n
  NameValue:~p ~n  AgeValue:~p ~n ", [?MODULE, ?LINE, NameValue, AgeValue]),
  BackData = binary_to_list(<<NameValue/bits, <<":">>/bits, AgeValue/bits>>),
  {reply, BackData, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling cast messages
%%
%% @end
%%--------------------------------------------------------------------
-spec(handle_cast(Request :: term(), State :: #state{}) ->
  {noreply, NewState :: #state{}} |
  {noreply, NewState :: #state{}, timeout() | hibernate} |
  {stop, Reason :: term(), NewState :: #state{}}).
handle_cast(_Request, State) ->
  {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling all non call/cast messages
%%
%% @spec handle_info(Info, State) -> {noreply, State} |
%%                                   {noreply, State, Timeout} |
%%                                   {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
-spec(handle_info(Info :: timeout() | term(), State :: #state{}) ->
  {noreply, NewState :: #state{}} |
  {noreply, NewState :: #state{}, timeout() | hibernate} |
  {stop, Reason :: term(), NewState :: #state{}}).
handle_info(_Info, State) ->
  {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
%%
%% @spec terminate(Reason, State) -> void()
%% @end
%%--------------------------------------------------------------------
-spec(terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
    State :: #state{}) -> term()).
terminate(_Reason, _State) ->
  ok.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Convert process state when code is changed
%%
%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @end
%%--------------------------------------------------------------------
-spec(code_change(OldVsn :: term() | {down, term()}, State :: #state{},
    Extra :: term()) ->
  {ok, NewState :: #state{}} | {error, Reason :: term()}).
code_change(_OldVsn, State, _Extra) ->
  {ok, State}.


%%%===================================================================
%%% Internal functions
%%%===================================================================


get_user(Name, Connection, Req) ->
  Selector = {Name, <<"undefined">>},
  Collection = <<"user">>,
  Cursor = mongo:find(Connection, Collection, Selector),
  Result = mc_cursor:rest(Cursor),
  [Head | _] = Result,
  {_, _, _, NameValue, _, AgeValue} = Head,
  BackData = binary_to_list(<<NameValue/bits, <<":">>/bits, AgeValue/bits>>).











%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
hello_erlang_app.erl
%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
-module(hello_erlang_app).
-behaviour(application).

-export([start/2]).
-export([stop/1]).

start(_Type, _Args) ->

  %% init cowboy
  Dispatch = cowboy_router:compile([
    {'_', [{"/user/[:user_name]", hello_handler, []}]}
  ]),
  cowboy:start_http(my_http_listener, 100, [{port, 8080}],
    [{env, [{dispatch, Dispatch}]}]
  ),
  io:format("Cowboy inited Line 22 ~n "),
  hello_erlang_sup:start_link().

stop(_State) ->
  ok.




%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
hello_erlang_sup.erl
%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
-module(hello_erlang_sup).
-behaviour(supervisor).

-export([start_link/0]).
-export([init/1]).

start_link() ->
  supervisor:start_link({local, ?MODULE}, ?MODULE, []).

init([]) ->
  %% init mongodb
  {ok, Pools} = application:get_env(hello_erlang, mongodb_pools),
  io:format("**********************************************************************Pools is ~n ~p ~n ", [Pools]),
  PoolSpecs =
    lists:map(
      fun({Name, SizeArgs, WorkerArgs}) ->
        PoolArgs = [{name, {local, Name}}, {worker_module, db_mongo_handler}] ++ SizeArgs,
        io:format("****************************************************************Name is ~n  ~p ~n ", [Name]),
        io:format("****************************************************************SizeArgs is ~n ~p ~n ", [SizeArgs]),
        io:format("****************************************************************WorkerArgs is ~n ~p ~n ", [WorkerArgs]),
        poolboy:child_spec(Name, PoolArgs, WorkerArgs)
      end,
      Pools),
  io:format("**********************************************************************PoolsSpecs:re ~n ~p ~n", [PoolSpecs]),
  io:format("**********************************************************************Poolboy has exited: ~n ~p ~n", [poolboy:module_info()]),
  {ok, {{one_for_one, 10, 10}, PoolSpecs}}.

%%
%%   {ok, Pools} = application:get_env(hello_erlang, mongodb_pools),
%%   PoolSpecs = lists:map(fun({Name, SizeArgs, WorkerArgs}) ->
%%     PoolArgs = [{name, {local, Name}},
%%       {worker_module, db_mongo_handler}] ++ SizeArgs,
%%     poolboy:child_spec(Name, PoolArgs, WorkerArgs)
%%   end, Pools),
%%   {ok, {{one_for_one, 10, 10}, [PoolSpecs]}}.



%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
hello_handler.erl
%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
-module(hello_handler).
-behaviour(cowboy_http_handler).

-export([init/3]).
-export([handle/2]).
-export([terminate/3]).

-define(DB_Conn_Pool, mg_pool1).
init(_, Req, Opts) ->
  {ok, Req, Opts}.

handle(Req, State) ->
  case cowboy_req:method(Req) of
    {<<"GET">>, Req2} ->
      {UserName, Req3} = cowboy_req:binding(user_name, Req2),
      io:format("***************************Debug*********************************~n  Module:~p ~n  Line:~p ~n  UserName:~p ~n", [?MODULE, ?LINE, UserName]),
      get_user(UserName, Req3);
    {<<"DELETE">>, Req2} ->
      {UserName, Req3} = cowboy_req:binding(user_name, Req2),
      delete_user(UserName, Req3);
    {<<"POST">>, Req2} ->
      {ok, Body, Req3} = cowboy_req:body(Req2),
      UserInfo = jiffy:decode(Body),
      {[{<<"name">>, NameValue}, {<<"age">>, AgeValue}]} = UserInfo,
      io:format("--Body is ~p ~n  --UserInfo is ~p ~n --NameValue is ~p ~n --AgeValue is ~p ~n", [Body, UserInfo, NameValue, AgeValue]),
      add_user(NameValue, AgeValue, Req3);
    {<<"PUT">>, Req2} ->
      {ok, Body, Req3} = cowboy_req:body(Req2),
      UserInfo = jiffy:decode(Body),
      {[{<<"name">>, NameValue}, {<<"age">>, AgeValue}]} = UserInfo,
      io:format("--Body is ~p ~n  --UserInfo is ~p ~n --NameValue is ~p ~n --AgeValue is ~p ~n", [Body, UserInfo, NameValue, AgeValue]),
      update_user(NameValue, AgeValue, Req3)

  end.


get_user(Name, Req) ->
  Collection = <<"user">>,
  Selector = {name, Name},
  Worker = poolboy:checkout(?DB_Conn_Pool),
  io:format("***************************Debug*********************************~n  Module:~p ~n  Line:~p ~n  Worker:~p ~n", [?MODULE, ?LINE, Worker]),
  Request = {get_user, {Collection, Selector}},
  UserInfo = gen_server:call(Worker, Request),
  io:format("***************************Debug*********************************~n  Module:~p ~n  Line:~p ~n  UserInfo:~p ~n", [?MODULE, ?LINE, UserInfo]),
  cowboy_req:reply(200, [
    {<<"content-type">>, <<"text/plain">>}
  ], UserInfo, Req).


%% Add user
add_user(Name, Age, Req) ->
  {Database, Collection} = {<<"user">>, <<"user">>},
  {ok, Connection} = mongo:connect("127.0.0.1", 27017, Database),
  mongo:insert(Connection, Collection, [{name, Name, age, Age}]).


%%Update user
update_user(Name, Age, Req) ->
  {Database, Collection} = {<<"user">>, <<"user">>},
  {ok, Connection} = mongo:connect("127.0.0.1", 27017, Database),
  Command = {'$set', {age, Age}},
  mongo:update(Connection, Collection, {name, Name}, Command).

%%Delete user
delete_user(Name, Req) ->
  {Database, Collection} = {<<"user">>, <<"user">>},
  {ok, Connection} = mongo:connect("127.0.0.1", 27017, Database),
  Selector = {name, Name},
  mongo:delete(Connection, Collection, Selector).


terminate(_Reason, _Req, _State) ->
  ok.





%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
start.erl
%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%
-module(start).
-author("zhouhuakang").

%% API
-export([]).
-export([
  start_applications/1, stop_applications/1, server_start/0]).
-define(SERVER_APPS, [sasl,ranch,crypto,cowlib,cowboy,bson,mongodb,jiffy,hello_erlang]).


server_start()->
  try
    ok = start_applications(?SERVER_APPS)
  after
    timer:sleep(100)
  end.


manage_applications(Iterate, Do, Undo, SkipError, ErrorTag, Apps) ->
  Iterate( fun (App, Acc) ->
    case Do(App) of
      ok -> [App | Acc];
      {error, {SkipError, _}} -> Acc;
      {error, Reason} ->
        lists:foreach(Undo, Acc),
        throw({error, {ErrorTag, App, Reason}})
    end
  end, [], Apps),
  ok.

start_applications(Apps) ->
  manage_applications(fun lists:foldl/3,
    fun application:start/1,
    fun application:stop/1,
    already_started,
    cannot_start_application,
    Apps).

stop_applications(Apps) ->
  manage_applications(fun lists:foldr/3,
    fun application:stop/1,
    fun application:start/1,
    not_started,
    cannot_stop_application,
    Apps).