如何用Python編寫一個聊天室

本課程整理於實驗樓

一、課程介紹

1.簡介

本次項目課是實現簡單聊天室程序的服務器端和客戶端。

2.知識點

服務器端涉及到asyncore、asynchat和socket這幾個模塊，客戶端用到了telnetlib、wx、time和thread這幾個模塊。

3.所需環境

本次課中編寫客戶端需要用到wxPython，它是一個GUI工具包，請先使用下麵的命令安裝：

$ sudo apt-get install python-wxtools

密碼為shiyanlou

4.項目效果截圖

登錄窗口

聊天窗口

5.源代碼下載

git clone https://github.com/shiyanlou/pythonchat.git

說明：如果你不理解上述代碼的下載方式或者下載後在環境中找不到代碼，可以點擊查看這裡

二、項目實戰（服務器端）

1.服務器類

首先需要一個聊天服務器，這裡繼承asyncore的dispatcher類來實現，代碼如下

class ChatServer(dispatcher):
    """
    聊天服務器
    """

    def __init__(self, port):
        dispatcher.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.set_reuse_addr()
        self.bind(('', port))
        self.listen(5)
        self.users = {}
        self.main_room = ChatRoom(self)

    def handle_accept(self):
        conn, addr = self.accept()
        ChatSession(self, conn)

2.會話類

有了服務器類還需要能維護每個用戶的連接會話，這裡繼承asynchat的async_chat類來實現，代碼如下：

class ChatSession(async_chat):
    """
    負責和單用戶通信
    """

    def __init__(self, server, sock):
        async_chat.__init__(self, sock)
        self.server = server
        self.set_terminator('n')
        self.data = []
        self.name = None
        self.enter(LoginRoom(server))

    def enter(self, room):
        '從當前房間移除自身，然後添加到指定房間'
        try:
            cur = self.room
        except AttributeError:
            pass
        else:
            cur.remove(self)
        self.room = room
        room.add(self)

    def collect_incoming_data(self, data):
        '接受客戶端的數據'
        self.data.append(data)

    def found_terminator(self):
        '當客戶端的一條數據結束時的處理'
        line = ''.join(self.data)
        self.data = []
        try:
            self.room.handle(self, line)
        except EndSession:
            self.handle_close()

    def handle_close(self):
        async_chat.handle_close(self)
        self.enter(LogoutRoom(self.server))

3.命令解釋器

現在就需要一個命令解釋器能夠解釋用戶的命令，例如登錄、查詢在線用戶和發消息等，代碼如下：

class CommandHandler:
    """
    命令處理類
    """

    def unknown(self, session, cmd):
        '響應未知命令'
        session.push('Unknown command: %sn' % cmd)

    def handle(self, session, line):
        '命令處理'
        if not line.strip():
            return
        parts = line.split(' ', 1)
        cmd = parts[0]
        try:
            line = parts[1].strip()
        except IndexError:
            line = ''
        meth = getattr(self, 'do_' + cmd, None)
        try:
            meth(session, line)
        except TypeError:
            self.unknown(session, cmd)

4.房間

接下來就需要實現聊天室的房間了，這裡我們定義了三種房間，分彆是用戶剛登錄時的房間、聊天的房間和退出登錄的房間，這三種房間都有一個公共的父類，代碼如下：

class Room(CommandHandler):
    """
    包含多個用戶的環境，負責基本的命令處理和廣播
    """

    def __init__(self, server):
        self.server = server
        self.sessions = []

    def add(self, session):
        '一個用戶進入房間'
        self.sessions.append(session)

    def remove(self, session):
        '一個用戶離開房間'
        self.sessions.remove(session)

    def broadcast(self, line):
        '向所有的用戶發送指定消息'
        for session in self.sessions:
            session.push(line)

    def do_logout(self, session, line):
        '退出房間'
        raise EndSession

class LoginRoom(Room):
    """
    剛登錄的用戶的房間
    """

    def add(self, session):
        '用戶連接成功的回應'
        Room.add(self, session)
        session.push('Connect Success')

    def do_login(self, session, line):
        '登錄命令處理'
        name = line.strip()
        if not name:
            session.push('UserName Empty')
        elif name in self.server.users:
            session.push('UserName Exist')
        else:
            session.name = name
            session.enter(self.server.main_room)

class ChatRoom(Room):
    """
    聊天用的房間
    """

    def add(self, session):
        '廣播新用戶進入'
        session.push('Login Success')
        self.broadcast(session.name + ' has entered the room.n')
        self.server.users[session.name] = session
        Room.add(self, session)

    def remove(self, session):
        '廣播用戶離開'
        Room.remove(self, session)
        self.broadcast(session.name + ' has left the room.n')

    def do_say(self, session, line):
        '客戶端發送消息'
        self.broadcast(session.name + ': ' + line + 'n')

    def do_look(self, session, line):
        '查看在線用戶'
        session.push('Online Users:n')
        for other in self.sessions:
            session.push(other.name + 'n')

class LogoutRoom(Room):
    """
    用戶退出時的房間
    """

    def add(self, session):
        '從服務器中移除'
        try:
            del self.server.users[session.name]
        except KeyError:
            pass

5.服務器端完整代碼

#!/usr/bin/python
# encoding: utf-8

from asyncore import dispatcher
from asynchat import async_chat
import socket, asyncore

PORT = 6666 #端口

class EndSession(Exception):
    """
    自定義會話結束時的異常
    """
    pass

class CommandHandler:
    """
    命令處理類
    """

    def unknown(self, session, cmd):
        '響應未知命令'
        session.push('Unknown command: %sn' % cmd)

    def handle(self, session, line):
        '命令處理'
        if not line.strip():
            return
        parts = line.split(' ', 1)
        cmd = parts[0]
        try:
            line = parts[1].strip()
        except IndexError:
            line = ''
        meth = getattr(self, 'do_' + cmd, None)
        try:
            meth(session, line)
        except TypeError:
            self.unknown(session, cmd)

class Room(CommandHandler):
    """
    包含多個用戶的環境，負責基本的命令處理和廣播
    """

    def __init__(self, server):
        self.server = server
        self.sessions = []

    def add(self, session):
        '一個用戶進入房間'
        self.sessions.append(session)

    def remove(self, session):
        '一個用戶離開房間'
        self.sessions.remove(session)

    def broadcast(self, line):
        '向所有的用戶發送指定消息'
        for session in self.sessions:
            session.push(line)

    def do_logout(self, session, line):
        '退出房間'
        raise EndSession

class LoginRoom(Room):
    """
    剛登錄的用戶的房間
    """

    def add(self, session):
        '用戶連接成功的回應'
        Room.add(self, session)
        session.push('Connect Success')

    def do_login(self, session, line):
        '登錄命令處理'
        name = line.strip()
        if not name:
            session.push('UserName Empty')
        elif name in self.server.users:
            session.push('UserName Exist')
        else:
            session.name = name
            session.enter(self.server.main_room)

class ChatRoom(Room):
    """
    聊天用的房間
    """

    def add(self, session):
        '廣播新用戶進入'
        session.push('Login Success')
        self.broadcast(session.name + ' has entered the room.n')
        self.server.users[session.name] = session
        Room.add(self, session)

    def remove(self, session):
        '廣播用戶離開'
        Room.remove(self, session)
        self.broadcast(session.name + ' has left the room.n')

    def do_say(self, session, line):
        '客戶端發送消息'
        self.broadcast(session.name + ': ' + line + 'n')

    def do_look(self, session, line):
        '查看在線用戶'
        session.push('Online Users:n')
        for other in self.sessions:
            session.push(other.name + 'n')

class LogoutRoom(Room):
    """
    用戶退出時的房間
    """

    def add(self, session):
        '從服務器中移除'
        try:
            del self.server.users[session.name]
        except KeyError:
            pass

class ChatSession(async_chat):
    """
    負責和單用戶通信
    """

    def __init__(self, server, sock):
        async_chat.__init__(self, sock)
        self.server = server
        self.set_terminator('n')
        self.data = []
        self.name = None
        self.enter(LoginRoom(server))

    def enter(self, room):
        '從當前房間移除自身，然後添加到指定房間'
        try:
            cur = self.room
        except AttributeError:
            pass
        else:
            cur.remove(self)
        self.room = room
        room.add(self)

    def collect_incoming_data(self, data):
        '接受客戶端的數據'
        self.data.append(data)

    def found_terminator(self):
        '當客戶端的一條數據結束時的處理'
        line = ''.join(self.data)
        self.data = []
        try:
            self.room.handle(self, line)
        except EndSession:
            self.handle_close()

    def handle_close(self):
        async_chat.handle_close(self)
        self.enter(LogoutRoom(self.server))

class ChatServer(dispatcher):
    """
    聊天服務器
    """

    def __init__(self, port):
        dispatcher.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.set_reuse_addr()
        self.bind(('', port))
        self.listen(5)
        self.users = {}
        self.main_room = ChatRoom(self)

    def handle_accept(self):
        conn, addr = self.accept()
        ChatSession(self, conn)

if __name__ == '__main__':
    s = ChatServer(PORT)
    try:
        asyncore.loop()
    except KeyboardInterrupt:
        print

三、項目實戰（客戶端）

完成了服務器端後，就需要實現客戶端了，這裡客戶端連接服務器使用了telnetlib模塊。

1.登錄窗口

這裡的圖形界麵包選擇了wxPython，前麵有安裝說明，登錄窗口通過繼承wx.Frame類來實現，代碼如下：

class LoginFrame(wx.Frame):
    """
    登錄窗口
    """

    def __init__(self, parent, id, title, size):
        '初始化，添加控件並綁定事件'
        wx.Frame.__init__(self, parent, id, title)
        self.SetSize(size)
        self.Center()
        self.serverAddressLabel = wx.StaticText(self, label = "Server Address", pos = (10, 50), size = (120, 25))
        self.userNameLabel = wx.StaticText(self, label = "UserName", pos = (40, 100), size = (120, 25))
        self.serverAddress = wx.TextCtrl(self, pos = (120, 47), size = (150, 25))
        self.userName = wx.TextCtrl(self, pos = (120, 97), size = (150, 25))
        self.loginButton = wx.Button(self, label = 'Login', pos = (80, 145), size = (130, 30))
        self.loginButton.Bind(wx.EVT_BUTTON, self.login)
        self.Show()

    def login(self, event):
        '登錄處理'
        try:
            serverAddress = self.serverAddress.GetLineText(0).split(':')
            con.open(serverAddress[0], port = int(serverAddress[1]), timeout = 10)
            response = con.read_some()
            if response != 'Connect Success':
                self.showDialog('Error', 'Connect Fail!', (95, 20))
                return
            con.write('login ' + str(self.userName.GetLineText(0)) + 'n')
            response = con.read_some()
            if response == 'UserName Empty':
                self.showDialog('Error', 'UserName Empty!', (135, 20))
            elif response == 'UserName Exist':
                self.showDialog('Error', 'UserName Exist!', (135, 20))
            else:
                self.Close()
                ChatFrame(None, -2, title = 'ShiYanLou Chat Client', size = (500, 350))
        except Exception:
            self.showDialog('Error', 'Connect Fail!', (95, 20))

    def showDialog(self, title, content, size):
        '顯示錯誤信息對話框'
        dialog = wx.Dialog(self, title = title, size = size)
        dialog.Center()
        wx.StaticText(dialog, label = content)
        dialog.ShowModal()

2.聊天窗口

聊天窗口中最主要的就是向服務器發消息並接受服務器的消息，這裡通過子線程來接受，代碼如下：

class ChatFrame(wx.Frame):
    """
    聊天窗口
    """

    def __init__(self, parent, id, title, size):
        '初始化，添加控件並綁定事件'
        wx.Frame.__init__(self, parent, id, title)
        self.SetSize(size)
        self.Center()
        self.chatFrame = wx.TextCtrl(self, pos = (5, 5), size = (490, 310), style = wx.TE_MULTILINE | wx.TE_READONLY)
        self.message = wx.TextCtrl(self, pos = (5, 320), size = (300, 25))
        self.sendButton = wx.Button(self, label = "Send", pos = (310, 320), size = (58, 25))
        self.usersButton = wx.Button(self, label = "Users", pos = (373, 320), size = (58, 25))
        self.closeButton = wx.Button(self, label = "Close", pos = (436, 320), size = (58, 25))
        self.sendButton.Bind(wx.EVT_BUTTON, self.send)
        self.usersButton.Bind(wx.EVT_BUTTON, self.lookUsers)
        self.closeButton.Bind(wx.EVT_BUTTON, self.close)
        thread.start_new_thread(self.receive, ())
        self.Show()

    def send(self, event):
        '發送消息'
        message = str(self.message.GetLineText(0)).strip()
        if message != '':
            con.write('say ' + message + 'n')
            self.message.Clear()

    def lookUsers(self, event):
        '查看當前在線用戶'
        con.write('lookn')

    def close(self, event):
        '關閉窗口'
        con.write('logoutn')
        con.close()
        self.Close()

    def receive(self):
        '接受服務器的消息'
        while True:
            sleep(0.6)
            result = con.read_very_eager()
            if result != '':
                self.chatFrame.AppendText(result)

3.客戶端完整代碼

#!/usr/bin/python
# encoding: utf-8

import wx
import telnetlib
from time import sleep
import thread

class LoginFrame(wx.Frame):
    """
    登錄窗口
    """

    def __init__(self, parent, id, title, size):
        '初始化，添加控件並綁定事件'
        wx.Frame.__init__(self, parent, id, title)
        self.SetSize(size)
        self.Center()
        self.serverAddressLabel = wx.StaticText(self, label = "Server Address", pos = (10, 50), size = (120, 25))
        self.userNameLabel = wx.StaticText(self, label = "UserName", pos = (40, 100), size = (120, 25))
        self.serverAddress = wx.TextCtrl(self, pos = (120, 47), size = (150, 25))
        self.userName = wx.TextCtrl(self, pos = (120, 97), size = (150, 25))
        self.loginButton = wx.Button(self, label = 'Login', pos = (80, 145), size = (130, 30))
        self.loginButton.Bind(wx.EVT_BUTTON, self.login)
        self.Show()

    def login(self, event):
        '登錄處理'
        try:
            serverAddress = self.serverAddress.GetLineText(0).split(':')
            con.open(serverAddress[0], port = int(serverAddress[1]), timeout = 10)
            response = con.read_some()
            if response != 'Connect Success':
                self.showDialog('Error', 'Connect Fail!', (95, 20))
                return
            con.write('login ' + str(self.userName.GetLineText(0)) + 'n')
            response = con.read_some()
            if response == 'UserName Empty':
                self.showDialog('Error', 'UserName Empty!', (135, 20))
            elif response == 'UserName Exist':
                self.showDialog('Error', 'UserName Exist!', (135, 20))
            else:
                self.Close()
                ChatFrame(None, -2, title = 'ShiYanLou Chat Client', size = (500, 350))
        except Exception:
            self.showDialog('Error', 'Connect Fail!', (95, 20))

    def showDialog(self, title, content, size):
        '顯示錯誤信息對話框'
        dialog = wx.Dialog(self, title = title, size = size)
        dialog.Center()
        wx.StaticText(dialog, label = content)
        dialog.ShowModal()

class ChatFrame(wx.Frame):
    """
    聊天窗口
    """

    def __init__(self, parent, id, title, size):
        '初始化，添加控件並綁定事件'
        wx.Frame.__init__(self, parent, id, title)
        self.SetSize(size)
        self.Center()
        self.chatFrame = wx.TextCtrl(self, pos = (5, 5), size = (490, 310), style = wx.TE_MULTILINE | wx.TE_READONLY)
        self.message = wx.TextCtrl(self, pos = (5, 320), size = (300, 25))
        self.sendButton = wx.Button(self, label = "Send", pos = (310, 320), size = (58, 25))
        self.usersButton = wx.Button(self, label = "Users", pos = (373, 320), size = (58, 25))
        self.closeButton = wx.Button(self, label = "Close", pos = (436, 320), size = (58, 25))
        self.sendButton.Bind(wx.EVT_BUTTON, self.send)
        self.usersButton.Bind(wx.EVT_BUTTON, self.lookUsers)
        self.closeButton.Bind(wx.EVT_BUTTON, self.close)
        thread.start_new_thread(self.receive, ())
        self.Show()

    def send(self, event):
        '發送消息'
        message = str(self.message.GetLineText(0)).strip()
        if message != '':
            con.write('say ' + message + 'n')
            self.message.Clear()

    def lookUsers(self, event):
        '查看當前在線用戶'
        con.write('lookn')

    def close(self, event):
        '關閉窗口'
        con.write('logoutn')
        con.close()
        self.Close()

    def receive(self):
        '接受服務器的消息'
        while True:
            sleep(0.6)
            result = con.read_very_eager()
            if result != '':
                self.chatFrame.AppendText(result)

'程序運行'
if __name__ == '__main__':
    app = wx.App()
    con = telnetlib.Telnet()
    LoginFrame(None, -1, title = "Login", size = (280, 200))
    app.MainLoop()

四、小結

最後就可以運行程序進行聊天了，注意需要先啟動服務器再啟動客戶端。這個項目中使用了asyncore的dispatcher來實現服務器，asynchat的asyn_chat來維護用戶的連接會話，用wxPython來實現圖形界麵，用telnetlib來連接服務器，在子線程中接受服務器發來的消息，由此一個簡單的聊天室程序就完成了。