Explain XKCD Comic Bot

#!/usr/bin/python
#coding: utf-8
"""
This bot reads data from xkcd.com and creates the appropriate pages.
This bot is designed specifically for explainxkcd.com.
No changes are made if the pages already exist.

Specific arguments:
-test           Don't actually make any changes
-latest         Create pages for the latest comic
-all            Create pages for all comics
-start:xxx      Specify the comic number to start at (inclusive).
                This requires -all. Defaults to 1.
-end:xxx        Specify the comic number to end at (inclusive).
                This requires -all. Defaults to 99999.

Example usage:
# Make sure everthing is set up properly, but don't actually do anything
python xkcd.py -latest -test
# Add pages for the latest comic (if they don't exist yet)
python xkcd.py -latest
# Add pages for all comics (if they don't exist yet)
python xkcd.py -all
# Add pages for comics 50-100 (if they don't exist yet)
python xkcd.py -all -start:50 -end:100
"""
#
# Distributed under the terms of the MIT license.
#
#
# This script is based on pagefromfile.py, which has the following license:
#
## (C) Andre Engels, 2004
## (C) Pywikipedia bot team, 2005-2010
##
## Distributed under the terms of the MIT license.
#
__version__='$Id$'
#

import re
import wikipedia as pywikibot
import urllib
import json
import datetime
import upload

def formatComicPage(data, imageFilename):
    # Parse the date
    date = datetime.date(int(data['year']), int(data['month']), int(data['day']))
    # Format as "August 01, 2012", then replace "01" with "1"
    dateText = re.sub(r"\b0([0-9])\b", r"\1", date.strftime("%B %d, %Y"))
    # Return the contents of the comic page
    return """{{ComicHeader|%d|%s}}

[[File:%s|%s]]

== Image Text ==
%s

== Description ==
This comic doesn't have a description yet. Why don't you add one?
""" % (data['num'], dateText, imageFilename, data['alt'], data['alt'])

class XKCDRobot:

    def __init__(self, test, createAll, createLatest, start, end):
        self.test = test
        self.createAll = createAll
        self.createLatest = createLatest
        self.start = start
        self.end = end

    def run(self):
        pywikibot.output(u"")
        if self.test:
            pywikibot.output(u"TESTING - Nothing will actually be done.")
        if self.createLatest:
            self.addLatestComic()
        if self.createAll:
            self.addAllComics()

    def addAllComics(self):
        pywikibot.output(u"Adding all comics from %d to %d..." % (self.start, self.end))
        num = self.start
        while num <= self.end:
            try:
                pywikibot.output(u"Reading comic data for %d..." % num)
                data = self.getComicData(num)
                pywikibot.output(u"Read comic data (%s: '%s')." % (data['num'], data['safe_title']))
            except ValueError:
                # Likely a 404, which means we're done
                break
            self.addComic(data)
            num += 1

    def addLatestComic(self):
        pywikibot.output(u"Reading latest comic data...")
        data = self.getComicData()
        pywikibot.output(u"Read latest comic data (%s: %s)." % (data['num'], data['safe_title']))
        self.addComic(data)

    def getComicData(self, num = None):
        if num == None:
            # Latest
            url = "http://xkcd.com/info.0.json"
        else:
            url = "http://xkcd.com/%d/info.0.json" % num
        return json.load(urllib.urlopen(url))

    def addComic(self, data):
        self.createRedirectPage(data)
        self.createComicPage(data)

    def createRedirectPage(self, data):
        page = self.getPage(str(data['num']))
        if not page.exists():
            pywikibot.output(u"Creating redirect page for %s..." % data['num'])
            contents = "#REDIRECT [[%s]]" % data['safe_title']
            self.writePage(page, contents, "Created page with redirect to '%s'." % data['safe_title'])
            pywikibot.output(u"Created redirect page." % data['num'])
        else:
            pywikibot.output(u"Redirect page already exists for %s." % data['num'])

    def createComicPage(self, data):
        page = self.getPage(data['safe_title'])
        if not page.exists():
            # Upload image first
            imageFilename = data['safe_title'].replace(" ", "_") + ".png"
            pywikibot.output(u"Uploading image '%s' for %s..." % (imageFilename, data['num']))
            if not self.test:
                uploadBot = upload.UploadRobot(data['img'], \
                                               description="Image for comic '%s'" % data['safe_title'], \
                                               useFilename = imageFilename, \
                                               verifyDescription = False, \
                                               targetSite = pywikibot.getSite(), \
                                               uploadByUrl=True)
            pywikibot.output(u"Uploaded image.")
            pywikibot.output(u"Creating comic page '%s' for %s..." % (data['safe_title'], data['num']))
            contents = formatComicPage(data, imageFilename)
            self.writePage(page, contents, "Created comic stub")
            pywikibot.output(u"Created comic page.")
        else:
            pywikibot.output(u"Comic page already exists for %s." % data['num'])

    def getPage(self, name):
        mysite = pywikibot.getSite()
        page = pywikibot.Page(mysite, name)
        return page

    def writePage(self, page, contents, comment):
        try:
            if not self.test:
                page.put(contents, comment = comment)
        except pywikibot.LockedPage:
            pywikibot.output(u"Page is locked; skipping.")
        except pywikibot.EditConflict:
            pywikibot.output(u'Skipping because of edit conflict')
        except pywikibot.SpamfilterError, error:
            pywikibot.output(
                u'Cannot change because of spam blacklist entry %s'
                % (error.url))

def main():
    createAll = False
    createLatest = False
    test = False
    start = 1
    end = 99999

    for arg in pywikibot.handleArgs():
        if arg.startswith("-start:"):
            start = int(arg[7:])
        elif arg.startswith("-end:"):
            end = int(arg[5:])
        elif arg == "-latest":
            createLatest = True
        elif arg == "-all":
            createAll = True
        elif arg == "-test":
            test = True
        else:
            pywikibot.output(u"Disregarding unknown argument %s." % arg)

    bot = XKCDRobot(test, createAll, createLatest, start, end)
    bot.run()

if __name__ == "__main__":
    try:
        main()
    finally:
        pywikibot.stopme()