obama fever

OBAMA WON! Truly a day to remember. So, in the spirit of science funding not being slashed to death I am going to release one of my first python scripts that downloads all images off of the NASA Astronomy Picture of the Day (apod).

I tried keeping the code commented so that it could also serve as a good learning tool. One thing I'd like to include is some way of saving the description of the image. This could be done by saving it into a text file with the same filename as the image, but I suspect there is a better way (using ImageMagick to embed the information?). If you have an idea or preference, post a comment! So, here it goes:

#!/bin/env python
#
# Copyright 2008 Michael Gorelick 
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see:
# http://www.gnu.org/licenses/gpl.html.

import re, urllib, sys, os

### Check/Do Help
help = """NASA Image Getter - Michael G. (GPL 2008)
./%s [-h] [imagepath]
imagepath  - path to save images
-h, --help - this help"""%sys.argv[0]

if "-h" in sys.argv or "--help" in sys.argv:
exit(help)
elif len(sys.argv) == 1:
print "Not enough program arguments"
exit(help)

### CONFIG
allowedChars = '[-a-zA-Z0-9*:\'.,&!?\(\)//\n"+;_ ]'
allowedFiles = '[jpg|jpeg|png|gif|mov|avi|mpeg|mpg]'
url = "http://antwrp.gsfc.nasa.gov/apod/archivepix.html"
pbarwidth = 80
try:
imagePath = sys.argv[1]
os.makedirs(imagePath)
except Exception, e:
#errno == 17 means the directory already exists.
if e.errno != 17:
 exit(e)
print "Saving images to %s"%imagePath

##############################################
## This section looks for links to image pages
print "Searching for image pages in", url
html = urllib.urlopen(url).read()
pagePattern = re.compile('([0-9]{6}).html">(' + allowedChars + '*)')
pages = pagePattern.findall(html)
totalpages = len(pages)
print "Found", totalpages, "image pages."

#############################################
## Now we go to the pages and extract a list
##  of images and download
try:
alreadyHave = open(imagePath + "/tracker.log").readlines()
except IOError, e:
alreadyHave = ""
totalhave = len(alreadyHave)
try:
tracker = open(imagePath + "/tracker.log", 'a+')
except IOError, e:
exit(e)

base = url[0:url.rfind('/')]
imagePattern = re.compile('<a href="image/(' + allowedChars + '*.' + \
allowedFiles + ')"', re.IGNORECASE)
sanitizePattern = re.compile('[//\n\r\t]')
imageGet = urllib.URLopener()

for i, page in enumerate(pages):
try:
 if page[0]+"\n" not in alreadyHave:
   #Extract information from image page
   title = sanitizePattern.sub("", page[1])
   currentpage = base + "/ap" + page[0] + ".html"
   print "Getting " + title
   content = urllib.urlopen(currentpage).read()
   image = imagePattern.findall(content)

   #Parse data
   filename = imagePath + "/" + (title + \
     image[0][image[0].rfind('.'):]).replace(" ","_")
   print "\tFilename: " + filename
   url = base + "/image/" + image[0]
   print "\tURL: " + url

   print "\n[" + "="*(pbarwidth*(i-totalhave)/(totalpages-totalhave)) \
     +"@"+"="*(pbarwidth*(i-totalpages)/(totalhave-totalpages)-1)+"]",
   sys.stdout.flush()

   #Download
   imageGet.retrieve(url, filename)
   tracker.write(page[0] + "\n")

   print "\r" + " "*(pbarwidth+2),"\r",
   sys.stdout.flush()
except IndexError, e:
 print "\tImage not found\n"
except IOError, e:
 print "\t404 Error\n"

tracker.close()
print "Done"