Erlang与ActionScript3采用JSON格式进行Socket通讯

前提：
需要下载as3corelib来为ActionScript3处理JSON codec

server.erl

-module(server).
-export([start/0,start/1,process/1]).
-define(defPort, 8888).

start() -> start(?defPort).

start(Port) ->
  case gen_tcp:listen(Port, [binary, {packet, 0}, {active, false}]) of
    {ok, LSock} -> server_loop(LSock);
    {error, Reason} -> exit({Port,Reason})
  end.

%% main server loop - wait for next connection, spawn child to process it
server_loop(LSock) ->
  case gen_tcp:accept(LSock) of
    {ok, Sock} ->
      spawn(?MODULE,process,[Sock]),
      server_loop(LSock);
    {error, Reason} ->
      exit({accept,Reason})
  end.

%% process current connection
process(Sock) ->
  Req = do_recv(Sock),
  io:format("~p~n", [Req]),
  {ok, D, []} = rfc4627:decode(Req),
  {obj, [{"name", _Name}, {"age", Age}]} = D,
  Name = binary_to_list(_Name),
  io:format("Name: ~p, Age: ~p~n", [Name, Age]),
  Resp = rfc4627:encode({obj, [{"name", 'Hideto2'}, {"age", 24}]}),
  do_send(Sock,Resp),
  gen_tcp:close(Sock).

%% send a line of text to the socket
do_send(Sock,Msg) ->
  case gen_tcp:send(Sock, Msg) of
    ok -> ok;
    {error, Reason} -> exit(Reason)
  end.

%% receive data from the socket
do_recv(Sock) ->
  case gen_tcp:recv(Sock, 0) of
    {ok, Bin} -> binary_to_list(Bin);
    {error, closed} -> exit(closed);
    {error, Reason} -> exit(Reason)
  end.

Person.as

package
{
	public class Person
	{
		public var name:String;
		public var age:int;
		public function Person()
		{
		}
	}
}

Client.as

package {
	import com.adobe.serialization.json.JSON;
	
	import flash.display.Sprite;
	import flash.events.*;
	import flash.net.Socket;
	import flash.text.*;
	
	public class Client extends Sprite
	{
		private var socket:Socket;
		private var myField:TextField;
		private var send_data:Person;
		public function Client()
		{
			socket = new Socket();
			myField = new TextField();
			send_data = new Person();
			send_data.name = "Hideto";
			send_data.age = 23;
			socket.addEventListener(ProgressEvent.SOCKET_DATA, onSocketData);
			socket.connect("localhost", 8888);
			socket.writeUTFBytes(JSON.encode(send_data));
			socket.flush();
			myField.x = 20;
			myField.y = 30;
			myField.text = "test";
			myField.autoSize = TextFieldAutoSize.LEFT;
			addChild(myField);
		}
		private function onSocketData(event:ProgressEvent):void {
			while(socket.bytesAvailable) {
				var recv_data:* = JSON.decode(socket.readUTFBytes(socket.bytesAvailable));
				myField.text = "Name: " + recv_data.name + ", age: " + recv_data.age.toString();
			}
		}
	}
}

运行Erlang服务器端：

Eshell> c(server).
Eshell> server:start().
"{\"name\":\"Hideto\",\"age\":23}"
Name: "Hideto", Age: 23

这里打印出了Erlang Socket Server接收到的AS3 Client发过来的JSON decode过的一个person对象

运行AS3客户端：
client.html上首先显示“test”，然后异步处理完Socket消息发送和接受后，decode Erlang Server端发过来的person对象，将页面上的TextField替换为“Name: Hideto2, age: 24”

评论

2 楼 hittyo 2009-11-10  

rfc4627:encode  这个哪来的

1 楼 rambobb 2009-03-03  

好像com.adobe.serialization.json.JSON 有bug...

import com.adobe.serialization.json.JSON;

var obj:Object = new Object();
for (var i:int = 0; i < 20; i++)
obj["t" + i] = i;

trace(JSON.encode(obj));

多试几下，就会看到输出不一样的字符串，例如
{"t5":5,"t9":9,"t11":11,"t7":7,"t0":0,"t18":18,"t15":15,"t6":6,"t19":19,"t1":1,"t3":3,"t12":12,"t10":10,"t14":14,"t8":8,"t4":4,"t17":17,"t2":2,"t13":13,"t16":16}
{"t2":2,"t19":19,"t9":9,"t11":11,"t16":16,"t12":12,"t6":6,"t7":7,"t4":4,"t18":18,"t10":10,"t8":8,"t17":17,"t3":3,"t14":14,"t5":5,"t13":13,"t0":0,"t1":1,"t15":15}

这样的话，用{obj, [{"name", _Name}, {"age", Age}]} = D,  的方式解析，有时候就会不匹配。

用get_field/2，但效率也就比前面的低很多。。。

头痛~~