Four Views of a Book Press by 802

You’re all probably tired of hearing me talking about my script to split the XML-like file that WordPress generates when you use the Export feature. Tonight I have finally added the final touches to it and can now share it here with you.

If you don’t remember, I wrote it because my good friend Evandro from QuartoEstudio.com is always getting asked by some of his clients to migrate an existing web blog to a new host/domain and hands him a tarball containing the exported content of a WordPress blog in XML format. The problem resides on the issue that some web hosting providers will limit how big a file can be uploaded via a POST method, and depending on how big this XML file is, you may have to manually break it into smaller files first.

Along the way I learned a bit more about OptParse, LXML and Beautiful Soup, so the entire experience was very productive and fun. In the end, I solved my issue by simple using the *strip_cdata=False* argument to the XMLParser class. Got to love when the solution is that simple!

So, without further ado, I present you ChoppedPress(download)! In the next few days (or weeks, depending on what my schedule looks like) I will make it more robust and add more error handling, etc. In the meantime, I hope you will find it useful.

# -*- coding: utf-8 -*-

"""
Copyright (c) 2010, Og Maciel

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted
provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this list of
      conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, this list
      of conditions and the following disclaimer in the documentation and/or other materials
      provided with the distribution.
    * Neither the name of the Og Maciel nor the names of its contributors may be used to
      endorse or promote products derived from this software without specific prior written
      permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""

import os
import sys

try:
    from lxml import etree
except ImportError:
    print "Please install lxml and try again: http://codespeak.net/lxml/"
    sys.exit(-1)

from optparse import OptionParser

# This is the default xml tag for wordpress
WP_TAG = "/rss/channel/item"
OUTFILE = "outfile"
CHUNKSIZE = 2
TMPFILE = "/tmp/template.xml"

# Function found on ActiveState Code
# Licensed under the PSF license
# http://code.activestate.com/recipes/425397-split-a-list-into-roughly-equal-sized-pieces/
def split_seq(seq, size):
    newseq = []
    splitsize = 1.0/size*len(seq)
    for i in range(size):
            newseq.append(seq[int(round(i*splitsize)):int(round((i+1)*splitsize))])

    return newseq

def chopit(xmlfile, outfile=OUTFILE, xmltag=WP_TAG, chunksize=CHUNKSIZE):
    parser = etree.XMLParser(resolve_entities=False, encoding="utf-8", strip_cdata=False)
    doc = etree.parse(xmlfile, parser)

    matches = doc.xpath(xmltag)
    print "Found %s blog posts!" % len(matches)
    matcheslist = split_seq(matches, chunksize)

    channel = doc.getroot().find('channel')

    # Create an empty wordpress xml file
    for e in matches:
        channel.remove(e)
    doc.write(TMPFILE, encoding="utf-8", method="xml", pretty_print=True)

    # Now, create smaller wordpress xml files
    ctr = len(matcheslist)
    print "Breaking WordPress XML into %s smaller files." % ctr
    for entities in matcheslist:
        doc = etree.parse(TMPFILE)
        channel = doc.getroot().find('channel')
        for entity in entities:
            channel.append(entity)

        output = '%s%03d.xml' % (outfile, ctr)
        doc.write(output, encoding='utf-8', method="xml", pretty_print=True)
        print " - File %s has %s posts." % (output, len(entities))
        ctr -= 1
    print "Done!"

def main():

    description = "ChoppedPress lets you split the WordPress XML export file "
    "into smaller files that can be used to import your posts, comments, tags"
    " and categories into a new WordPress installation."

    usage = "Usage:  %prog  [[] [] []]"
    epilog = "Constructive comments and feedback can be sent to ogmaciel at gnome dot org."
    version = "%prog version 0.1"

    parser = OptionParser(usage=usage, description=description, epilog=epilog, version=version)
    parser.add_option('-i', '--infile', dest='infile', metavar='', help='The XML file generated by WordPress')
    parser.add_option('-o', '--outfile', dest='outfile', default='out', metavar='', help='The name for the smaller XML files. [default: %default]')
    parser.add_option('-t', '--tag', dest='tag', default='/rss/channel/item', help='The XML tag that represents your data. [default: %default]')
    parser.add_option('-n', '--number', dest='number', default=2, type=int, help='How many new files should be generated. [default: %default]')

    # Verify arguments
    (opts, args) = parser.parse_args()

    if not opts.infile:
        parser.print_help()
        sys.exit(-1)

    chopit(opts.infile, opts.outfile, opts.tag, opts.number)

if __name__ == "__main__":
    main()

The usage should be pretty straight forward too:

$ python choppedpress
Usage:  choppedpress  <INFILE> [[<OUTFILE>] [<TAG>] [<NUMBER>]]

ChoppedPress lets you split the WordPress XML export file into smaller files
that can be used to import your posts, comments, tags and categories into a
new WordPress installation.

Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  -i , --infile=
                        The XML file generated by WordPress
  -o , --outfile=
                        The name for the smaller XML files. [default: out]
  -t TAG, --tag=TAG     The XML tag that represents your data. [default:
                        /rss/channel/item]
  -n NUMBER, --number=NUMBER
                        How many new files should be generated. [default: 2]

Constructive comments and feedback can be sent to ogmaciel at gnome dot org.

If you have any constructive comment or suggestion, please drop me a line or comment here.


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