Programming Forums > Script Programming > Other Scripting Languages

bulio · Jan 19th, 2007, 9:24 PM

Ok, I got it working. Here's what I have:

from os import path
from urllib import urlopen
from urlparse import urlsplit
from BeautifulSoup import BeautifulSoup
from httplib import InvalidURL
 
savedir = 'E:\Documents and Settings\Mark-James McDougall\Desktop\DTA'
 
url = 'http://bombingscience.com/graffitiforum/index.php?showtopic=4900&st=%s'
 
main_url = 'http://bombingscience.com/'
 
 
for i in range(0, 526):
 
  this_url = url % i
 
  try:
    soup = BeautifulSoup(urlopen(this_url))
 
  except InvalidURL, e:
    print 'url <%s> did not open: %s' % (this_url, e)
    print sys.exit(1)
 
  for img in soup.findAll('img'):
    src = img['src']
 
    # if it's from the ad server, let's ignore this image
    if 'adserver' in src:
      print 'This looks like an ad, skipping: %s' % src
      continue
 
    if not src.startswith('http://'):
      image_url = main_url + src.strip('/')
    else:
      image_url = src
 
    try:
      image = urlopen(image_url).read()
      relative_path = urlsplit(src)[2]
 
      filename = relative_path.split('/')[-1]
 
      open(path.join(savedir, filename), 'wb').write(image)
      print 'got %s successfully' % image_url
 
    except IOError, e:
      print 'could not open this image: <%s>' % image_url

Although, it seems that a bunch of images get downloaded and some work properly, but others don't appear on my PC. The size and filename is there, but no image.

Any idea why?

Arevos · Jan 20th, 2007, 6:57 AM

Quote:

Originally Posted by bulio

Although, it seems that a bunch of images get downloaded and some work properly, but others don't appear on my PC. The size and filename is there, but no image.

Any idea why?

I'm not sure. Have you tried visiting the URLs that failed with a browser?

The only thing I can think of is that perhaps the relative URLs aren't being correctly parsed. Try replacing these lines:

 python Syntax (Toggle Plain Text) 
    if not src.startswith('http://'):
      image_url = main_url + src.strip('/')
    else:
      image_url = src
    if not src.startswith('http://'):
      image_url = main_url + src.strip('/')
    else:
      image_url = src

With this:

python Syntax (Toggle Plain Text)

    image_url = urljoin(this_url, src)

And add urljoin to the list of functions you import from urlparse:

 python Syntax (Toggle Plain Text) 
from urlparse import urlsplit, urljoin
from urlparse import urlsplit, urljoin

urljoin will turn any relative link into an absolute one, whilst leaving absolute URLs intact. e.g.

 python Syntax (Toggle Plain Text) 
>>> urljoin("http://www.foo.com", "bar/foobar.png")
"http://www.foo.com/bar/foobar.png"
>>> urljoin("http://www.foo.com", "http://www.world.com/bar/foobar.png")
"http://www.world.com/bar/foobar.png"
>>> urljoin("http://www.foo.com", "bar/foobar.png")
"http://www.foo.com/bar/foobar.png"
>>> urljoin("http://www.foo.com", "http://www.world.com/bar/foobar.png")
"http://www.world.com/bar/foobar.png"

Your code does the same thing, but there may be URLs it falls over on, giving an incorrect final URL. urljoin should work correctly for any valid URL. Whether this is the problem, I'm not sure, but it's the only thing I can currently think of.

Also, you have:

(Toggle Plain Text)

for i in range(0, 526)

Which will go up by increments of 1 each time. The URLs, however, go up in increments of 15 (e.g. st=0, st=15, st=30...) :

(Toggle Plain Text)

for i in range(0, 526, 15)

Whilst either should work, you're probably iterating over the same posts multiple times.

Duck · Jan 20th, 2007, 11:08 AM

(you could use HtTrack to download the website (or parts of) then you'd have all the image files etc)

bulio · Jan 21st, 2007, 12:24 PM

Areos, your code works great! Now if only I could find out how to only download the images, not the signatures or avatars

bulio · Jan 21st, 2007, 2:15 PM

Oh and finally, what would I need to change if I wanted to begin downloading images from say, page 300 of a forum thread?

I'm assuming I'd change:

(Toggle Plain Text)

for i in range(0, 526, 15)

To this:

(Toggle Plain Text)

 for i in range(4500, 526, 15)

Since st=4500 would be the 300th page.

Also, it seems like around 40-60 images didn't get downloaded. Any idea why soem are getting downloaded no problem, but some aren't?

Arevos · Jan 21st, 2007, 3:01 PM

The arguments in range are (start, end, increment). The first argument is the starting number, the second is the number after the ending number, the third is the increment.

So (0, 526, 15) will go from 0 to 525 in increments of 15. range(4500, 526, 15) won't do anything, since the end (526) is less than the start(4500).

bulio · Jan 21st, 2007, 3:14 PM

I don't understand why some images are getting downloaded fine, when others aren't even getting downloaded at all. For example:

http://bombingscience.com/graffitifo...ic=4900&st=450

Not one of those images were downloaded.

Arevos · Jan 21st, 2007, 4:45 PM

Did the page load correctly or did it timeout? Did the program say the images were being downloaded?

Perhaps if you farmed out the functionality to a method, then you could call it just for page 450. Something like:

 python Syntax (Toggle Plain Text) 
for i in range(0, 526, 15):
    save_images(url % i)
for i in range(0, 526, 15):
    save_images(url % i)

And then if you wanted to check a particular page:

 python Syntax (Toggle Plain Text) 
save_images(url % 450)
save_images(url % 450)

I tested it on 450, and it seems to work fine. Perhaps the page is timing out, or maybe it doesn't like you requesting so many pages so quickly. Perhaps put in a "time.sleep" function at the end of the loop to ensure that it waits a few seconds before the next page.

Jan 19th, 2007, 9:24 PM	#11
bulio Hobbyist Programmer Join Date: Jul 2004 Location: Location Posts: 138 Rep Power: 5	Ok, I got it working. Here's what I have: (Toggle Plain Text) from os import path from urllib import urlopen from urlparse import urlsplit from BeautifulSoup import BeautifulSoup from httplib import InvalidURL savedir = 'E:\Documents and Settings\Mark-James McDougall\Desktop\DTA' url = 'http://bombingscience.com/graffitiforum/index.php?showtopic=4900&st=%s' main_url = 'http://bombingscience.com/' for i in range(0, 526): this_url = url % i try: soup = BeautifulSoup(urlopen(this_url)) except InvalidURL, e: print 'url <%s> did not open: %s' % (this_url, e) print sys.exit(1) for img in soup.findAll('img'): src = img['src'] # if it's from the ad server, let's ignore this image if 'adserver' in src: print 'This looks like an ad, skipping: %s' % src continue if not src.startswith('http://'): image_url = main_url + src.strip('/') else: image_url = src try: image = urlopen(image_url).read() relative_path = urlsplit(src)[2] filename = relative_path.split('/')[-1] open(path.join(savedir, filename), 'wb').write(image) print 'got %s successfully' % image_url except IOError, e: print 'could not open this image: <%s>' % image_url from os import path from urllib import urlopen from urlparse import urlsplit from BeautifulSoup import BeautifulSoup from httplib import InvalidURL savedir = 'E:\Documents and Settings\Mark-James McDougall\Desktop\DTA' url = 'http://bombingscience.com/graffitiforum/index.php?showtopic=4900&st=%s' main_url = 'http://bombingscience.com/' for i in range(0, 526): this_url = url % i try: soup = BeautifulSoup(urlopen(this_url)) except InvalidURL, e: print 'url <%s> did not open: %s' % (this_url, e) print sys.exit(1) for img in soup.findAll('img'): src = img['src'] # if it's from the ad server, let's ignore this image if 'adserver' in src: print 'This looks like an ad, skipping: %s' % src continue if not src.startswith('http://'): image_url = main_url + src.strip('/') else: image_url = src try: image = urlopen(image_url).read() relative_path = urlsplit(src)[2] filename = relative_path.split('/')[-1] open(path.join(savedir, filename), 'wb').write(image) print 'got %s successfully' % image_url except IOError, e: print 'could not open this image: <%s>' % image_url Although, it seems that a bunch of images get downloaded and some work properly, but others don't appear on my PC. The size and filename is there, but no image. Any idea why?

Jan 21st, 2007, 2:15 PM	#15
bulio Hobbyist Programmer Join Date: Jul 2004 Location: Location Posts: 138 Rep Power: 5	Oh and finally, what would I need to change if I wanted to begin downloading images from say, page 300 of a forum thread? I'm assuming I'd change: (Toggle Plain Text) for i in range(0, 526, 15) for i in range(0, 526, 15) To this: (Toggle Plain Text) for i in range(4500, 526, 15) for i in range(4500, 526, 15) Since st=4500 would be the 300th page. Also, it seems like around 40-60 images didn't get downloaded. Any idea why soem are getting downloaded no problem, but some aren't? Last edited by bulio; Jan 21st, 2007 at 2:35 PM.

Jan 21st, 2007, 4:45 PM	#18
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 4	Did the page load correctly or did it timeout? Did the program say the images were being downloaded? Perhaps if you farmed out the functionality to a method, then you could call it just for page 450. Something like: python Syntax (Toggle Plain Text) for i in range(0, 526, 15): save_images(url % i) for i in range(0, 526, 15): save_images(url % i) And then if you wanted to check a particular page: python Syntax (Toggle Plain Text) save_images(url % 450) save_images(url % 450) I tested it on 450, and it seems to work fine. Perhaps the page is timing out, or maybe it doesn't like you requesting so many pages so quickly. Perhaps put in a "time.sleep" function at the end of the loop to ensure that it waits a few seconds before the next page.

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Jan 20th, 2007, 11:08 AM	#13
Duck Programmer Join Date: Jun 2006 Location: England London Posts: 72 Rep Power: 3	(you could use HtTrack to download the website (or parts of) then you'd have all the image files etc)

Jan 21st, 2007, 12:24 PM	#14
bulio Hobbyist Programmer Join Date: Jul 2004 Location: Location Posts: 138 Rep Power: 5	Areos, your code works great! Now if only I could find out how to only download the images, not the signatures or avatars

Jan 21st, 2007, 3:01 PM	#16
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 4	The arguments in range are (start, end, increment). The first argument is the starting number, the second is the number after the ending number, the third is the increment. So (0, 526, 15) will go from 0 to 525 in increments of 15. range(4500, 526, 15) won't do anything, since the end (526) is less than the start(4500).

Jan 21st, 2007, 3:14 PM	#17
bulio Hobbyist Programmer Join Date: Jul 2004 Location: Location Posts: 138 Rep Power: 5	I don't understand why some images are getting downloaded fine, when others aren't even getting downloaded at all. For example: http://bombingscience.com/graffitifo...ic=4900&st=450 Not one of those images were downloaded.

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How could I do this?