wxPython 线程下载

Question

我需要在 wxPython 应用程序中下载 url 列表，但我对线程非常陌生，谁能告诉我一个如何下载链接并将输出放入 wx 控件的工作示例。

Answer 1

很高兴看到您为至少尝试完成这一目标所做的一切。不管怎样，有一些很好的资源可以用来学习如何在 wxPython 中做线程。他们在这里：

• wiki.wxpython.org/LongRunningTasks
• http://www.blog.pythonlibrary.org/2010/05/22/wxpython-and-threads/

我写了一篇关于使用 urllib/urllib2 下载文件的教程，并在这里请求：

• http://www.blog.pythonlibrary.org/2012/06/07/python-101-how-to-download-a-file/

如果你把这三篇文章结合在一起，你就能得出你的答案。不过，我继续写了一个超级简单的下载器：

import requests
import os
import wx
import wx.lib.scrolledpanel as scrolled

from threading import Thread
from wx.lib.pubsub import pub

########################################################################
class DownloadThread(Thread):
    """Downloading thread"""

    #----------------------------------------------------------------------
    def __init__(self, gnum, url, fsize):
        """Constructor"""
        Thread.__init__(self)
        self.fsize = fsize
        self.gnum = gnum
        self.url = url
        self.start()

    #----------------------------------------------------------------------
    def run(self):
        """
        Run the worker thread
        """
        local_fname = os.path.basename(self.url)
        count = 1
        while True:
            if os.path.exists(local_fname):
                tmp, ext = os.path.splitext(local_fname)
                cnt = "(%s)" % count
                local_fname = tmp + cnt + ext
                count += 1
            else:
                break
        req = requests.get(self.url, stream=True)
        total_size = 0
        print local_fname
        with open(local_fname, "wb") as fh:
            for byte in req.iter_content(chunk_size=1024):
                if byte:
                    fh.write(byte)
                    fh.flush()
                total_size += 1024
                if total_size < self.fsize:
                    wx.CallAfter(pub.sendMessage, 
                                 "update_%s" % self.gnum,
                                 msg=total_size)
        print "DONE!"
        wx.CallAfter(pub.sendMessage,
                     "update_%s" % self.gnum,
                     msg=self.fsize)


########################################################################
class MyGauge(wx.Gauge):
    """"""

    #----------------------------------------------------------------------
    def __init__(self, parent, range, num):
        """Constructor"""
        wx.Gauge.__init__(self, parent, range=range)

        pub.subscribe(self.updateProgress, "update_%s" % num)

    #----------------------------------------------------------------------
    def updateProgress(self, msg):
        """"""
        self.SetValue(msg)

########################################################################
class MyPanel(scrolled.ScrolledPanel):
    """"""

    #----------------------------------------------------------------------
    def __init__(self, parent):
        """Constructor"""
        scrolled.ScrolledPanel.__init__(self, parent)

        self.data = []
        self.download_number = 1

        # create the sizers
        self.main_sizer = wx.BoxSizer(wx.VERTICAL)
        dl_sizer = wx.BoxSizer(wx.HORIZONTAL)

        # create the widgets
        lbl = wx.StaticText(self, label="Download URL:")
        self.dl_txt = wx.TextCtrl(self)
        btn = wx.Button(self, label="Download")
        btn.Bind(wx.EVT_BUTTON, self.onDownload)

        # layout the widgets
        dl_sizer.Add(lbl, 0, wx.ALL|wx.CENTER, 5)
        dl_sizer.Add(self.dl_txt, 1, wx.EXPAND|wx.ALL, 5)
        dl_sizer.Add(btn, 0, wx.ALL, 5)
        self.main_sizer.Add(dl_sizer, 0, wx.EXPAND)

        self.SetSizer(self.main_sizer)
        self.SetAutoLayout(1)
        self.SetupScrolling()

    #----------------------------------------------------------------------
    def onDownload(self, event):
        """
        Update display with downloading gauges
        """
        url = self.dl_txt.GetValue()
        try:
            header = requests.head(url)
            fsize = int(header.headers["content-length"]) / 1024

            sizer = wx.BoxSizer(wx.HORIZONTAL)
            fname = os.path.basename(url)
            lbl = wx.StaticText(self, label="Downloading %s" % fname)
            gauge = MyGauge(self, fsize, self.download_number)

            sizer.Add(lbl, 0, wx.ALL|wx.CENTER, 5)
            sizer.Add(gauge, 0, wx.ALL|wx.EXPAND, 5)
            self.main_sizer.Add(sizer, 0, wx.EXPAND)

            self.Layout()

            # start thread
            DownloadThread(self.download_number, url, fsize)

            self.download_number += 1
        except Exception, e:
            print "Error: ", e

########################################################################
class DownloaderFrame(wx.Frame):
    """"""

    #----------------------------------------------------------------------
    def __init__(self):
        """Constructor"""
        wx.Frame.__init__(self, None, title="Downloader", size=(800, 400))
        panel = MyPanel(self)
        self.Show()

#----------------------------------------------------------------------
if __name__ == "__main__":
    app = wx.App(False)
    frame = DownloaderFrame()
    app.MainLoop()

注意：您需要requests 才能使用此脚本。