listing28-2.py

《Beginning Python--From Novice to Professional》 的源码

from xmlrpclib import ServerProxy, Fault
from server import Node, UNHANDLED
from client import randomString
from threading import Thread
from time import sleep
from os import listdir
import sys
import wx

HEAD_START = 0.1 # Seconds
SECRET_LENGTH = 100


class ListableNode(Node):
    """
    An extended version of Node, which can list the files
    in its file directory.
    """
    def list(self):
        return listdir(self.dirname)

class Client(wx.App):
    """
    The main client class, which takes care of setting up the GUI and
    starts a Node for serving files.
    """
    def __init__(self, url, dirname, urlfile):
        """
        Creates a random secret, instantiates a ListableNode with that secret,
        starts a Thread with the ListableNode's _start method (making sure the
        Thread is a daemon so it will quit when the application quits),
        reads all the URLs from the URL file and introduces the Node to
        them. Finally, sets up the GUI.
        """
        self.secret = randomString(SECRET_LENGTH)
        n = ListableNode(url, dirname, self.secret)
        t = Thread(target=n._start)
        t.setDaemon(1)
        t.start()
        # Give the server a head start:
        sleep(HEAD_START)
        self.server = ServerProxy(url)
        for line in open(urlfile):
            line = line.strip()
            self.server.hello(line)
        # Get the GUI going:
        super(Client, self).__init__()

    def updateList(self):
        """
        Updates the list box with the names of the files available
        from the server Node.
        """
        self.files.Set(self.server.list())


    def OnInit(self):
        """
        Sets up the GUI. Creates a window, a text field, a button, and
        a list box, and lays them out. Binds the submit button to
        self.fetchHandler.
        """

        win = wx.Frame(None, title="File Sharing Client", size=(400, 300))

        bkg = wx.Panel(win)

        self.input = input = wx.TextCtrl(bkg);

        submit = wx.Button(bkg, label="Fetch", size=(80, 25))
        submit.Bind(wx.EVT_BUTTON, self.fetchHandler)

        hbox = wx.BoxSizer()

        hbox.Add(input, proportion=1, flag=wx.ALL | wx.EXPAND, border=10)
        hbox.Add(submit, flag=wx.TOP | wx.BOTTOM | wx.RIGHT, border=10)

        self.files = files = wx.ListBox(bkg)
        self.updateList()

        vbox = wx.BoxSizer(wx.VERTICAL)
        vbox.Add(hbox, proportion=0, flag=wx.EXPAND)
        vbox.Add(files, proportion=1,
                 flag=wx.EXPAND | wx.LEFT | wx.RIGHT | wx.BOTTOM, border=10)

        bkg.SetSizer(vbox)

        win.Show()

        return True

    def fetchHandler(self, event):
        """
        Called when the user clicks the 'Fetch' button. Reads the
        query from the text field, and calls the fetch method of the
        server Node. After handling the query, updateList is called.
        If the query is not handled, an error message is printed.
        """
        query = self.input.GetValue()
        try:
            self.server.fetch(query, self.secret)
            self.updateList()

        except Fault, f:
            if f.faultCode != UNHANDLED: raise
            print "Couldn't find the file", query

def main():
    urlfile, directory, url = sys.argv[1:]
    client = Client(url, directory, urlfile)
    client.MainLoop()

if __name__ == '__main__': main()