Check for `urllib.urlretrieve(url, file_name)` Completion Status

Question

How do I check to see if `urllib.urlretrieve(url, file_name)` has completed before allowing my program to advance to the next statement? Take for example the following code snippet: ``` import traceback import sys import Image from urllib import urlretrieve try: print "Downloading gif....." urlretrieve(imgUrl, "tides.gif") # Allow time for image to download/save: time.sleep(5) print "Gif Downloaded." except: print "Failed to Download new GIF" raw_input('Press Enter to exit...') sys.exit() try: print "Converting GIF to JPG...." Image.open("tides.gif").convert('RGB').save("tides.jpg") print "Image Converted" except Exception, e: print "Conversion FAIL:", sys.exc_info()[0] traceback.print_exc() pass ``` When the download of 'tides.gif' via `urlretrieve(imgUrl, "tides.gif")` takes longer than `time.sleep(seconds)` resulting in an empty or not-complete file, `Image.open("tides.gif")` raises an `IOError` (due to a tides.gif file of size 0 kB). How can I check the status of `urlretrieve(imgU…

Accepted Answer

Requests is nicer than urllib but you should be able to do this to synchronously download the file:

```
import urllib
f = urllib.urlopen(imgUrl)
with open("tides.gif", "wb") as imgFile:
    imgFile.write(f.read())
# you won't get to this print until you've downloaded
# all of the image at imgUrl or an exception is raised
print "Got it!"
```

The downside of this is it will need to buffer the whole file in memory so if you're downloading a lot of images at once you may end up using a ton of ram. It's unlikely, but still worth knowing.

Check for `urllib.urlretrieve(url, file_name)` Completion Status

Solution

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