最近開發 Erlang ,對其字符串處理能力無言至極,於是決定把它和python聯合起來,打造一個強力的分布式系統,等將來需要系統級開發時,我再把 C++/C組合進來.
首先參考了 Erlang 官方文檔和 http://blog.developers.api.sina.com.cn/?tag=erlang 以及 http://kazmier.net/computer/port-howto/ .
研讀了將近24個小時, 才終於完全把問題解決. 起名為town，town在英文裡表示集市，也就是代表各種語言在這裡的交流與互動。) )
-module(town).
-behaviour(gen_server).
%% API
-export([start/0,combine/1]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-record(state, {port}).
start() ->
gen_server:start_link({global, ?MODULE}, ?MODULE, [], []).
stop() ->
gen_server:cast(?SERVER, stop).
init([]) ->
process_flag(trap_exit, true),
Port = open_port({spawn, "python -u /home/freefis/Desktop/town.py"},[stream,{line, 1024}]),
{ok, #state{port = Port}}.
handle_call({combine,String}, _From, #state{port = Port} = State) ->
port_command(Port,String),
receive
{Port,{data,{_Flag,Data}}} ->
io:format("receiving:~p~n",[Data]),
sleep(2000),
{reply, Data, Port}
end.
handle_cast(stop, State) ->
{stop, normal, State};
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info(Info, State) ->
{noreply,State}.
terminate(_Reason, Port) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%--------------------------------------------------------------------
%%% Internal ---------------------------------------------------------
combine(_String) ->
start(),
String = list_to_binary("combine|"++_String++"\n"),
gen_server:call(?SERVER,{combine,String},infinity),
stop().這段是Python的腳本 當erlang中town:combine(“sentence1+sentence2”)執行時，會在後台啟動python的腳本，處理完畢後返回給Erlang結果:sentence1sentence2，然後退出。
import sys
def handle(_string):
if _string.startswith("combine|"):
string = "".join( _string[8:].split(","))
return string
"""waiting for input """
while 1:
# Recv. Binary Stream as Standard IN
_stream = sys.stdin.readline()
if not _stream: break
# Scheme, Turn into Formal String
inString = _stream.strip("\r\n")
# handle String
outString = handle(inString)
# send to port as Standart OUT
sys.stdout.write("%s\n" % (outString,))
sys.exit(0)
