Simple PyQt Progress Bar Downloader

progbarDownloader.py

#!/usr/bin/python3

# This is downloading class which uses python 3 with PyQt4. It shows how to use the
# QT progress bar in python. The downloading takes place in the UrlDownloader class
# which inherits from QThread.
#
# To test the widget:
# 1. try copying a URL that points to a large file.
# 2. Paste the file url into the combobox's text area, but do nothing more.
# 3. Copy another URL pointing to a large file.
# 4. Hit enter or the "Download" button.
# 5. Immediately clear the text field and enter the other URL.
#
# The status is displayed on the progress bar itself, in addition to a label on 
# the console.
#
# Abdalla S. Alothman

from PyQt4.QtCore import *
from PyQt4.QtGui import *
from progbarDownloaderWG import *
import sys, urllib.request

class ProgBarDownloader(QtGui.QWidget, Ui_ProgBarDownloader):
  def __init__(self, parent=None):
    QWidget.__init__(self, parent)
    self.ui = Ui_ProgBarDownloader()
    self.ui.setupUi(self)
    self.downloader = UrlDownloader()
    self.uList = list()

    self.ui.urlEdit.activated.connect(lambda: self.updateList(self.ui.urlEdit.currentText()))
    self.ui.startButton.clicked.connect(lambda: self.updateList(self.ui.urlEdit.currentText()))
    self.ui.urlEdit.activated.connect(lambda: self.download(self.ui.urlEdit.currentText()))
    self.ui.startButton.clicked.connect(lambda: self.download(self.ui.urlEdit.currentText()))
    self.downloader.progSig.connect(self.ui.progressBar.setValue)
    self.downloader.progStat[str].connect(self.ui.label.setText)
    self.downloader.doneSig.connect(self.ui.progressBar.reset)
    self.downloader.doneSig.connect(lambda: self.ui.label.setText(self.ui.label.text().replace("Saving", "Saved") + " - <b>Download Complete</b>."))
    self.downloader.sendNext[str].connect(self.clearLastUrl)
    self.downloader.doneSig.connect(self.ui.urlEdit.clearEditText)
    self.downloader.doneSig.connect(self.checkUList)

  def clearLastUrl(self, url):
    self.uList.remove(url)

  @pyqtSlot()
  def updateList(self, url):
    if not url in self.uList:
      self.uList.append(url)

  @pyqtSlot()
  def checkUList(self):
    if self.uList:
      self.ui.label.clear()
      for u in self.uList:
        _url = u
        self.download(_url)

  @pyqtSlot()
  def download(self, Url=str()):
    if Url is "" or not Url.startswith("http://"):
      return
    self.downloader.setUrl(Url)
    self.downloader.start()


class UrlDownloader(QThread):
  doneSig = pyqtSignal()
  progSig = pyqtSignal(int)
  progStat = pyqtSignal(str)
  sendNext = pyqtSignal(str)
  def __init__(self, parent=None):
    super(UrlDownloader, self).__init__(parent)
    self.url0 = str("")

  def setUrl(self, u):
    self.url0 = u

  def run(self):
    url =  self.url0
    print("Downloading from: {}".format(url))
    rq = urllib.request.urlopen(url)
    fSize = int(rq.info()['Content-Length'])
    fileName = url.split("/")[-1]
    downloadedChunk = 0
    blockSize = 2048 
    with open(fileName, "wb") as sura:
      while True:
        chunk = rq.read(blockSize)
        if not chunk:
          print("\nDownload Complete.")
          self.sendNext.emit(url)
          break
        downloadedChunk += len(chunk)
        sura.write(chunk)
        progress = float(downloadedChunk) / fSize
        self.progSig.emit(progress * 100)
        stat = r" Saving: {0} [{1:.2%}] of {2} bytes.".format(downloadedChunk, progress, fSize)
        stat2 = "<b>Saving {0}</b>: {1} [{2:.2%}] <b>of</b> {3} <b>bytes</b>.".format(fileName, downloadedChunk, progress, fSize)
        self.progStat.emit(stat2)
        stat = stat + chr(8) * (len(stat) + 1)
        sys.stdout.write(stat)
        sys.stdout.flush()
    self.doneSig.emit()

if __name__ == "__main__":
  import sys
  a = QApplication(sys.argv)
  progTester = ProgBarDownloader()
  progTester.show()
  sys.exit(a.exec_())

progbarDownloaderWG.py

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'progbarDownloader.ui'
#
# Created by: PyQt4 UI code generator 4.9.6
#
# WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    def _fromUtf8(s):
        return s

try:
    _encoding = QtGui.QApplication.UnicodeUTF8
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig)

class Ui_ProgBarDownloader(object):
    def setupUi(self, ProgBarDownloader):
        ProgBarDownloader.setObjectName(_fromUtf8("ProgBarDownloader"))
        ProgBarDownloader.resize(547, 96)
        self.gridLayout = QtGui.QGridLayout(ProgBarDownloader)
        self.gridLayout.setObjectName(_fromUtf8("gridLayout"))
        self.verticalLayout_2 = QtGui.QVBoxLayout()
        self.verticalLayout_2.setObjectName(_fromUtf8("verticalLayout_2"))
        self.horizontalLayout = QtGui.QHBoxLayout()
        self.horizontalLayout.setObjectName(_fromUtf8("horizontalLayout"))
        self.quitButton = QtGui.QPushButton(ProgBarDownloader)
        self.quitButton.setEnabled(True)
        self.quitButton.setObjectName(_fromUtf8("quitButton"))
        self.horizontalLayout.addWidget(self.quitButton)
        self.startButton = QtGui.QPushButton(ProgBarDownloader)
        self.startButton.setObjectName(_fromUtf8("startButton"))
        self.horizontalLayout.addWidget(self.startButton)
        self.urlEdit = QtGui.QComboBox(ProgBarDownloader)
        self.urlEdit.setMinimumSize(QtCore.QSize(350, 0))
        self.urlEdit.setEditable(True)
        self.urlEdit.setObjectName(_fromUtf8("urlEdit"))
        self.horizontalLayout.addWidget(self.urlEdit)
        self.verticalLayout_2.addLayout(self.horizontalLayout)
        self.verticalLayout = QtGui.QVBoxLayout()
        self.verticalLayout.setObjectName(_fromUtf8("verticalLayout"))
        self.label = QtGui.QLabel(ProgBarDownloader)
        self.label.setMinimumSize(QtCore.QSize(0, 25))
        font = QtGui.QFont()
        font.setPointSize(11)
        font.setBold(False)
        font.setWeight(50)
        self.label.setFont(font)
        self.label.setStyleSheet(_fromUtf8("background-color: rgb(50, 50, 50); color:rgb(204, 204, 255);"))
        self.label.setFrameShape(QtGui.QFrame.Box)
        self.label.setFrameShadow(QtGui.QFrame.Plain)
        self.label.setText(_fromUtf8(""))
        self.label.setAlignment(QtCore.Qt.AlignCenter)
        self.label.setObjectName(_fromUtf8("label"))
        self.verticalLayout.addWidget(self.label)
        self.progressBar = QtGui.QProgressBar(ProgBarDownloader)
        self.progressBar.setProperty("value", 0)
        self.progressBar.setObjectName(_fromUtf8("progressBar"))
        self.verticalLayout.addWidget(self.progressBar)
        self.verticalLayout_2.addLayout(self.verticalLayout)
        self.gridLayout.addLayout(self.verticalLayout_2, 0, 0, 1, 1)

        self.retranslateUi(ProgBarDownloader)
        QtCore.QObject.connect(self.urlEdit, QtCore.SIGNAL(_fromUtf8("currentIndexChanged(QString)")), self.urlEdit.setEditText)
        QtCore.QObject.connect(self.quitButton, QtCore.SIGNAL(_fromUtf8("clicked()")), ProgBarDownloader.close)
        QtCore.QMetaObject.connectSlotsByName(ProgBarDownloader)

    def retranslateUi(self, ProgBarDownloader):
        ProgBarDownloader.setWindowTitle(_translate("ProgBarDownloader", "Simple Progress Downloader", None))
        self.quitButton.setText(_translate("ProgBarDownloader", "Quit", None))
        self.startButton.setText(_translate("ProgBarDownloader", "Download", None))