How to write a download progress indicator in Python?

There's a text progress bar library for python at http://pypi.python.org/pypi/progressbar/2.2 that you might find useful:

This library provides a text mode progressbar. This is tipically used to display the progress of a long running operation, providing a visual clue that processing is underway.

The ProgressBar class manages the progress, and the format of the line is given by a number of widgets. A widget is an object that may display diferently depending on the state of the progress. There are three types of widget: - a string, which always shows itself; - a ProgressBarWidget, which may return a diferent value every time it's update method is called; and - a ProgressBarWidgetHFill, which is like ProgressBarWidget, except it expands to fill the remaining width of the line.

The progressbar module is very easy to use, yet very powerful. And automatically supports features like auto-resizing when available.

You might also try:

sys.stdout.write("\r%2d%%" % percent)
sys.stdout.flush()

Using a single carriage return at the beginning of your string rather than several backspaces. Your cursor will still blink, but it'll blink after the percent sign rather than under the first digit, and with one control character instead of three you may get less flicker.

For what it's worth, here's the code I used to get it working:

from urllib import urlretrieve
from progressbar import ProgressBar, Percentage, Bar

url = "http://......."
fileName = "file"
pbar = ProgressBar(widgets=[Percentage(), Bar()])
urlretrieve(url, fileName, reporthook=dlProgress)

def dlProgress(count, blockSize, totalSize):
    pbar.update( int(count * blockSize * 100 / totalSize) )

If you use the curses package, you have much greater control of the console. It also comes at a higher cost in code complexity and is probably unnecessary unless you are developing a large console-based app.

For a simple solution, you can always put the spinning wheel at the end of the status messge (the sequence of characters |, \, -, / which actually looks nice under blinking cursor.