Erlang 聊天室程序( 一)

              为了熟悉Erlang的套接字编程开始编写一个“聊天室”程序。基本流程如下：

             1.服务器启动监听指定端口

             2.启动一个gen_server 作为聊天室进程，里面使用ets 保持当前所有客户端连接信息，并负责将某个客户端的消息广播到所有在线客户端

             3.服务器接受客户端连接，并绑定到一个gen_server进程

             4.客户端维护进程接受客户端发送的消息，调用聊天室进程函数进行广播

             5.客户端维护进程接受聊天室发送的消息，转发给客户端

             客户端信息包括id、pid、socket、nickname、sex、age、province 等。

             目前包括以下几个模块：

           echatServer.erl  ：服务器端程序启动模块。

           chat_room.erl ：聊天室模块，一个gen_server负责处理客户端请求，保存了所有客户端的连接信息。

           id_generator.erl：负责为每一个连接的客户端生成唯一ID

           client_session.erl：与客户端socket绑定的gen_server回调模块，接收和发送消息

           chat_acceptor.erl：负责监听端口和处理连接的客户端socket

           代码如下：

           echatServer.erl:

          

-module(echatServer). %% %% Include files %% %% %% Exported Functions %% -export([start/0]). %% %% API Functions %% start()-> chat_room:start_link(), chat_acceptor:start(3377), ok.
           chat_room.erl: %% Author: Administrator %% Created: 2012-2-18 %% Description: TODO: Add description to chat_room %% 1.genPid for every client connection %% 2.broadcast message to all clientSessions -module(chat_room). -behaviour(gen_server). %% %% Include files %% -include("clientinfo.hrl"). -include("message.hrl"). -record(state,{}). %% %% Exported Functions %% -export([start_link/0,init/1,getPid/0,bindPid/2,broadCastMsg/1,logout/1]). -export([handle_call/3,handle_info/2,handle_cast/2,code_change/3,terminate/2]). %% %% API Functions %% start_link()-> gen_server:start_link({local,?MODULE}, ?MODULE, [],[]). %%to init all %%1.start id_generator %%2.create session table to store clientinfo %% init([])-> id_generator:start_link(), ets:new(clientinfo,[public, ordered_set, named_table, {keypos,#clientinfo.id} ]), {ok,#state{}} . handle_call({getpid,Id},From,State)-> {ok,Pid}=client_session:start_link(Id), {reply,Pid,State}; handle_call({remove_clientinfo,Ref},From,State)-> Key=Ref#clientinfo.id, ets:delete(clientinfo, Key) ; handle_call({sendmsg,Msg},From,State)-> Key=ets:first(clientinfo), io:format("feching talbe key is ~p~n",[Key]), sendMsg(Key,Msg), {reply,ok,State} . %%process messages handle_info(Request,State)-> {noreply,State}. handle_cast(_From,State)-> {noreply,State}. terminate(_Reason,_State)-> ok. code_change(_OldVersion,State,Ext)-> {ok,State}. %% %% Local Functions %% %% generate new Pid for eache conecting client getPid()-> Id=id_generator:getnewid(client), Pid=gen_server:call(?MODULE,{getpid,Id}), io:format("id generated ~w~n",[Id]), #clientinfo{id=Id,pid=Pid} . %%bind Pid to Socket %%create new record and store into table bindPid(Record,Socket)-> io:format("binding socket...~n"), case gen_tcp:controlling_process(Socket, Record#clientinfo.pid) of {error,Reason}-> io:format("binding socket...error~n"); ok -> NewRec =#clientinfo{id=Record#clientinfo.id,socket=Socket,pid=Record#clientinfo.pid}, io:format("chat_room:insert record ~p~n",[NewRec]), %store clientinfo to ets ets:insert(clientinfo, NewRec), %then we send info to clientSession to update it's State (Socket info) Pid=Record#clientinfo.pid, Pid!{bind,Socket}, io:format("clientBinded~n") %start client reciving %Pid!{start,Pid} end . %%generate random name %%and call setInfo(name) generatename()-> ok. %%broad CastMsg to all connected clientSessions broadCastMsg(Msg)-> gen_server:call(?MODULE, {sendmsg,Msg}). sendMsg(Key,Msg)-> case ets:lookup(clientinfo, Key)of [Record]-> io:format("Record found ~p~n",[Record]), Pid=Record#clientinfo.pid, %while send down we change msg type to dwmsg io:format("send smg to client_session ~p~n",[Pid]), Pid!{dwmsg,Msg}, Next=ets:next(clientinfo, Key), sendMsg(Next,Msg); []-> io:format("no clientinfo found~n") end , ok ; sendMsg([],Msg)-> ok. %%return all connected clientinfo to sender getMembers(From)-> ok. %%set clientinfo return ok or false %% when ok broadcast change %% user can changge name later setInfo(ClientInfo,From)-> ok. logout(Ref)-> gen_server:call(?MODULE, {remove_clientinfo,Ref}), ok.         id_generator.erl: %% Author: Administrator %% Created: 2012-2-16 %% Description: TODO: Add description to id_generator -module(id_generator). -behavior(gen_server). %% %% Include files %% %% %% Exported Functions %% -export([start_link/0,getnewid/1]). -export([init/1,handle_call/3,handle_cast/2,handle_info/2,terminate/2,code_change/3]). -record(ids,{idtype,ids}). -record(state,{}). %% %% API Functions %% start_link()-> gen_server:start_link({local,?MODULE}, ?MODULE, [],[]) . init([])-> mnesia:start(), io:format("Started"), mnesia:create_schema([node()]), case mnesia:create_table(ids,[{type,ordered_set}, {attributes,record_info(fields,ids)}, {disc_copies,[]} ]) of {atomic,ok}-> {atomic,ok}; {error,Reason}-> io:format("create table error") end, {ok,#state{}} . getnewid(IdType)-> %case mnesia:wait_for_tables([tbl_clientid], 5000) of % ok-> % gen_server:call(?MODULE, {getid,IdType}); % {timeout,_BadList}-> % {timeout,_BadList}; % {error,Reason}-> % {error,Reason} %end mnesia:force_load_table(ids), gen_server:call(?MODULE, {getid,IdType}) . %%generate new Id with given type handle_call({getid,IdType},From,State)-> F=fun()-> Result=mnesia:read(ids,IdType,write), case Result of [S]-> Id=S#ids.ids, NewClumn=S#ids{ids=Id+1}, mnesia:write(ids,NewClumn,write), Id; []-> NewClumn=#ids{idtype=IdType,ids=2}, mnesia:write(ids,NewClumn,write), 1 end end, case mnesia:transaction(F)of {atomic,Id}-> {atomic,Id}; {aborted,Reason}-> io:format("run transaction error ~1000.p ~n",[Reason]), Id=0; _Els-> Id=1000 end, {reply,Id,State} . handle_cast(_From,State)-> {noreply,ok}. handle_info(Request,State)-> {noreply,ok}. terminate(_From,State)-> ok. code_change(_OldVer,State,Ext)-> {ok,State}. %% %% Local Functions %%
       client_session.erl: %% Author: Administrator %% Created: 2012-2-16 %% Description: TODO: Add description to client_session -module(client_session). -behavior(gen_server). %% %% Include files %% -include("clientinfo.hrl"). -include("message.hrl"). %% %% Exported Functions %% -export([init/1,start_link/1,handle_info/2,handle_call/3,terminate/2]). -export([process_msg/1]). %% %% API Functions %% start_link(Id)-> gen_server:start_link(?MODULE, [Id], []) %gen_server:start_link({local,?MODULE}, ?MODULE, [Id],[]) . init(Id)-> State=#clientinfo{id=Id}, {ok,State}. %%handle message send from room handle_info({dwmsg,Message},State)-> io:format("client_session dwmsg recived ~p~n",[Message]), case gen_tcp:send(State#clientinfo.socket, Message#message.content)of ok-> io:format("client_session dwmsg sended ~n"); {error,Reason}-> io:format("client_session dwmsg sended error ~p ~n",Reason) end, {noreply,State}; %%handle message recived from client %handle_info(Message,State) when is_binary(Message)-> handle_info({bind,Socket},State)-> io:format("client_session bind socket ~n"), NewState=State#clientinfo{socket=Socket}, io:format("NewState ~p~n",[NewState]), {noreply,NewState}; %to start reciving %handle_info({start,Pid},State)-> % io:format("client_session:reciving start...~p~n",[State#clientinfo.socket]), % NewState=State#clientinfo{pid=Pid}, % process_msg(NewState), % {noreply,State}; handle_info({tcp,Socket,Data},State)-> io:format("client_session tcp data recived ~p~n",[Data]), %io:format("msg recived ~p~n",[Message]), NewMsg=#message{type=msg,from=State#clientinfo.id,content=Data}, chat_room:broadCastMsg(NewMsg), {noreply,State}; handle_info({tcp_closed,Socket},State)-> chat_room:logout(State); handle_info(stop,State)-> io:format("client stop"), {stop,normal,stopped,State}; handle_info(Request,State)-> io:format("client_session handle else ~p~n",[Request]), {noreply,State} . handle_call(Request,From,State)-> {reply,ok,State}. handle_cast(Request,State)-> {noreply,State}. terminate(_Reason,State)-> ok. %% %% Local Functions %% process_msg(State)-> io:format("client_session:process_msg SOCKET:~p ~n",[State#clientinfo.socket]), case gen_tcp:recv(State#clientinfo.socket, 0) of {ok,Message}-> io:format("recived ~p ~n",[Message]), %io:format("msg recived ~p~n",[Message]), NewMsg=#message{type=msg,from=State#clientinfo.id,content=Message}, chat_room:broadCastMsg(NewMsg), process_msg(State); {error,closed}-> io:format("client_session:recive error ~n"), process_msg(State); Any-> io:format("client_session:recive any ~n"), process_msg(State) end .
         chat_acceptor.erl: %% Author: Administrator %% Created: 2012-2-18 %% Description: TODO: Add description to chat_acceptor -module(chat_acceptor). %% %% Include files %% %% %% Exported Functions %% -export([start/1,accept_loop/1]). %% %% API Functions %% %%start listen server start(Port)-> case (do_init(Port))of {ok,ListenSocket}-> accept_loop(ListenSocket); _Els -> error end. %%listen port do_init(Port) when is_list(Port)-> start(list_to_integer(Port)) ; do_init([Port]) when is_atom(Port)-> start(list_to_integer(atom_to_list(Port))) ; do_init(Port) when is_integer(Port)-> Options=[binary, {packet, 0}, {reuseaddr, true}, {backlog, 1024}, {active, true}], case gen_tcp:listen(Port, Options) of {ok,ListenSocket}-> {ok,ListenSocket}; {error,Reason} -> {error,Reason} end. %%accept client connection accept_loop(ListenSocket)-> case (gen_tcp:accept(ListenSocket, 3000))of {ok,Socket} -> process_clientSocket(Socket), ?MODULE:accept_loop(ListenSocket); {error,Reason} -> ?MODULE:accept_loop(ListenSocket); {exit,Reason}-> ?MODULE:accept_loop(ListenSocket) end. %%process client socket %%we should start new thread to handle client %%generate new id using id_generator process_clientSocket(Socket)-> Record=chat_room:getPid(), chat_room:bindPid(Record, Socket), ok. %% %% Local Functions %%

                  为了测试这个服务器程序，我用JAVA写了个简单的client端程序，如下：

    MainForm.java

package com.kinglong.socket; import java.awt.BorderLayout; import java.awt.FlowLayout; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.Insets; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowEvent; import java.awt.event.WindowListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextArea; import javax.swing.JTextField; public class MainForm { private JFrame frame; private JPanel toolbar; private JTextArea outfile; private JTextField inpfile; SocketClient clientThread; public MainForm(){ final JButton send = new JButton("send"); outfile = new JTextArea(); inpfile = new JTextField(); clientThread = new SocketClient("***.***.***",3377,this); clientThread.start(); send.setActionCommand("send"); toolbar=new JPanel(); toolbar.setLayout(new BorderLayout()); toolbar.add(outfile,BorderLayout.CENTER); JPanel bottom =new JPanel(); bottom.setLayout(new GridBagLayout()); bottom.add(send,new GridBagConstraints(0,0,1,1, 0.0,0.0, GridBagConstraints.CENTER, GridBagConstraints.NONE, new Insets(2,2,2,2), 0,0)); bottom.add(inpfile,new GridBagConstraints(1,0,1,1, 0.0,0.0, GridBagConstraints.CENTER, GridBagConstraints.NONE, new Insets(2,2,2,2), 200,0)); toolbar.add(bottom,BorderLayout.SOUTH); ActionListener act = new ActionListener(){ @Override public void actionPerformed(ActionEvent e) { // TODO Auto-generated method stub if("send".equals(e.getActionCommand())){ clientThread.sendMsg(inpfile.getText()); inpfile.setText(""); } } }; send.addActionListener(act); frame = new JFrame(); frame.getContentPane().add(toolbar); frame.setSize(500,300); frame.setResizable(false); frame.setVisible(true); frame.addWindowListener(new WindowListener(){ @Override public void windowActivated(WindowEvent e) { // TODO Auto-generated method stub } @Override public void windowClosed(WindowEvent e) { // TODO Auto-generated method stub } @Override public void windowClosing(WindowEvent e) { // TODO Auto-generated method stub } @Override public void windowDeactivated(WindowEvent e) { // TODO Auto-generated method stub } @Override public void windowDeiconified(WindowEvent e) { // TODO Auto-generated method stub } @Override public void windowIconified(WindowEvent e) { // TODO Auto-generated method stub } @Override public void windowOpened(WindowEvent e) { // TODO Auto-generated method stub } }); } public void connect(){ } public void recMsg(String msgs){ String data =outfile.getText(); outfile.setText((data==null?"":data)+msgs+"\n"); } public static void main(String args[]){ MainForm form = new MainForm(); form.connect(); } }

             SocketClient.java

package com.kinglong.socket; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.Socket; import java.net.UnknownHostException; public class SocketClient extends Thread{ Socket clientSocket; InputStream inst; OutputStream oust; MainForm mf; boolean isrunning=true; public SocketClient(String ip,int port,MainForm mf){ try { clientSocket= new Socket(ip,port); inst = clientSocket.getInputStream(); oust = clientSocket.getOutputStream(); this.mf=mf; } catch (UnknownHostException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void sendMsg(String msg){ try { oust.write(msg.getBytes()); oust.flush(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } @Override public void run() { // TODO Auto-generated method stub InputStreamReader reader = new InputStreamReader(inst); BufferedReader bfreader = new BufferedReader(reader); while(isrunning){ String str=null; try { byte[] data =new byte[200]; int len =0; while((len=inst.read(data))>0){ str=new String(data).trim(); System.out.println("msg recived:"+str); mf.recMsg(str); } } catch (IOException e) { // TODO Auto-generated catch block System.out.println("recMsg error"+e.getMessage()); } try { Thread.sleep(500); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }

                  测试方法：

                  启动服务器端：

                       >echatServer:start().

                  启动两个客户端：

                        run as java Application

                  效果图：

发送：

发送：

                 服务器端打印出的日志：

Startedid generated 1 binding socket... chat_room:insert record {clientinfo,1,<0.102.0>,#Port<0.1778>,undefined, undefined,undefined,undefined,undefined, undefined,undefined} clientBinded client_session bind socket NewState {clientinfo,[1], undefined,#Port<0.1778>,undefined,undefined,undefined, undefined,undefined,undefined,undefined} id generated 2 binding socket... chat_room:insert record {clientinfo,2,<0.109.0>,#Port<0.1797>,undefined, undefined,undefined,undefined,undefined, undefined,undefined} clientBinded client_session bind socket NewState {clientinfo,[2], undefined,#Port<0.1797>,undefined,undefined,undefined, undefined,undefined,undefined,undefined} client_session tcp data recived <<"hello a">> feching talbe key is 1 Record found {clientinfo,1,<0.102.0>,#Port<0.1778>,undefined,undefined, undefined,undefined,undefined,undefined,undefined} send smg to client_session <0.102.0> Record found {clientinfo,2,<0.109.0>,#Port<0.1797>,undefined,undefined, undefined,undefined,undefined,undefined,undefined} client_session dwmsg recived {message,msg, [2], undefined,<<"hello a">>,undefined} send smg to client_session <0.109.0> client_session dwmsg sended no clientinfo found client_session dwmsg recived {message,msg, [2], undefined,<<"hello a">>,undefined} client_session dwmsg sended feching talbe key is 1 client_session tcp data recived <<"hello b">> Record found {clientinfo,1,<0.102.0>,#Port<0.1778>,undefined,undefined, undefined,undefined,undefined,undefined,undefined} send smg to client_session <0.102.0> Record found {clientinfo,2,<0.109.0>,#Port<0.1797>,undefined,undefined, undefined,undefined,undefined,undefined,undefined} send smg to client_session <0.109.0> no clientinfo found client_session dwmsg recived {message,msg, [1], undefined,<<"hello b">>,undefined} client_session dwmsg sended client_session dwmsg recived {message,msg, [1], undefined,<<"hello b">>,undefined} client_session dwmsg sended

至此基本的聊天功能实现了。顺便说下，以上的服务器端程序将监听到的socket连接交由单独的进程处理了。

还有不足就是客户端退出时会引发服务器端异常退出，这个需要对socket连接断开进行处理，下一步对这个进行修改。