scraper for /r/wallpapers

#!/usr/bin/python

#imports
import urllib2
import os
from array import array

#variables
sourceholder = ""
index = 0
indexstart = 0
indexend = 0
imagepaths = []
holder = ""
path = "/home/hojlind/Pictures/Wallpapers"
time = 600

#get the htmlcode
#response =
req = urllib2.Request('http://www.reddit.com/r/wallpapers')
req.add_unredirected_header('User-Agent', 'Hojlinds wallpaper getter')
sourceholder = urllib2.urlopen(req).read()

while index < len(sourceholder):
    indexstart = sourceholder.find("<a class=\"title \"", index)
    indexend = sourceholder.find("</a>", index)

    if indexend == -1:
        break

    #print "start" + str(indexstart)
    #print "end" + str(indexend)

    if sourceholder[indexstart : indexend].find("g") != -1 or sourceholder[indexstart : indexend].find("jpg") != -1 or sourceholder[indexstart : indexend].find("imgur") != -1:
        imagepaths.append(sourceholder[indexstart : indexend + 4])

    index = indexend + 4

#only sort the images we have a direct link to
for i in range(len(imagepaths)):

    indexstart = imagepaths[i].find("href=")

    indexend = imagepaths[i].find("jpg")

    if indexend == -1 :
        indexend = imagepaths[i].find("png")

    imagepaths[i] = imagepaths[i][indexstart + 6 : indexend + 3]

#remove all empty elements
imagepaths = filter(None, imagepaths)

#get the pictures
if not os.path.exists(path):
    os.makedirs(path)

for i in range(len(imagepaths)):
    if imagepaths[i].find("jpg") != -1 :
        filename = "wallpaper" + str(i) + ".jpg"

    else :
        filename = "wallpaper" + str(i) + ".png"

    f = open(os.path.join(path, filename), "w")

    reqImage = urllib2.Request(imagepaths[i])
    reqImage.add_unredirected_header('User-Agent', 'Hojlinds wallpaper getter')

    f.write(urllib2.urlopen(reqImage).read())

    f.close()

#write all images into the xml file so that the slideshow actually works
#first open the file and set up all the static stuff
filename = "changer.xml"

f = open(os.path.join(path, filename), "w")

f.write("<background>\n<starttime>\n<year>2009</year>\n<month>08</month>\n<day>04</day>\n<hour>00</hour>\n<minute>00</minute>\n<second>00</second>\n</starttime>")

for i in range(len(imagepaths)) :

    if imagepaths[i].find("jpg") != -1 :
        filename = "wallpaper" + str(i) + ".jpg"

    else :
        filename = "wallpaper" + str(i) + ".png"

    if i > 0 :

        if imagepaths[i-1].find("jpg") != -1 :
            prevfilename = "wallpaper" + str(i-1) + ".jpg"

        else :
            prevfilename = "wallpaper" + str(i-1) + ".png"

        f.write("<transition>\n<duration>5.0</duration>\n<from>" + str(os.path.join(path, prevfilename)) + "</from>\n<to>" + str(os.path.join(path, filename)) + "</to>\n</transition>")

    f.write("<static>\n<duration>" + str(time) + "</duration>\n<file>" + str(os.path.join(path, filename)) + "</file>\n</static>")

    if i == (len(imagepaths) - 1) :

        if imagepaths[0].find("jpg") != -1 :
            prevfilename = "wallpaper" + str(i-1) + ".jpg"

        else :
            prevfilename = "wallpaper" + str(i-1) + ".png"

        f.write("<transition>\n<duration>5.0</duration>\n<from>" + str(os.path.join(path, filename)) + "</from>\n<to>" + str(os.path.join(path, prevfilename)) + "</to>\n</transition>")


f.write("</background>")