Skip to main content
Help us improve Python packaging – donate today!

Compares two XML documents by diffing their text, ignoring structure, and wraps changed text in <del>/<ins> tags.

Project Description

Compares the text inside two XML documents and marks up the differences with <del> and <ins> tags.

This is the result of about 7 years of trying to get this right and coded simply. I’ve used code like this in one form or another to compare bill text on GovTrack.us <https://www.govtrack.us>.

The comparison is completely blind to the structure of the two XML documents. It does a word-by-word comparison on the text content only, and then it goes back into the original documents and wraps changed text in new <del> and <ins> wrapper elements.

The documents are then concatenated to form a new document and the new document is printed on standard output. Or use this as a library and call compare yourself with two lxml.etree.Element nodes (the roots of your documents).

The script is written in Python 3. The module works with any Google Diff Match Patch-compatible differencing library. You provide it a differ function which takes two strings and returns a list of (op, length) tuples, where op is “+” (insertion), “-” (deletion), or “0” (no change). If will use my extension module <https://github.com/JoshData/diff_match_patch-python> if it is available, falling back on the pure-Python <https://code.google.com/p/google-diff-match-patch/source/browse/trunk/python3/diff_match_patch.py> if it is available, or else the not very useful Python built-in difflib.

Example

Comparing these two documents:

<html>
        Here is <b>some bold</b> text.
</html>

and:

<html>
        Here is <i>some italic</i> content that shows how <tt>xml_diff</tt> works.
</html>

Yields:

<documents>
        <html>
                Here is <b>some <del>bold</del></b><del> text</del>.
        </html>
        <html>
                Here is <i>some <ins>italic</ins></i><ins> content that shows how </ins><tt><ins>xml_diff</ins></tt><ins> works</ins>.
        </html>
</documents>

First install the module:

pip install xml_diff

On Ubuntu, apt-get installing python3-lxml or libxml2-dev and libxslt1-dev might be necessary. When installing from source, you’ll need lxml too (but pip will get it for you automatically).

Then call the module from the command line:

python -m xml_diff  --tags del,ins doc1.xml doc2.xml > changes.xml

For really fast comparisons, get Google’s Diff Match Patch library <https://code.google.com/p/google-diff-match-patch/>, as re-written and sped-up by @leutloff <https://github.com/leutloff/diff-match-patch-cpp-stl> and then turned into a Python extension module by me <https://github.com/JoshData/diff_match_patch-python>:

pip install diff_match_patch_python

The command-line tool (above) will use this library if it is available.

Use the module from Python like so:

import lxml.etree
from xml_diff import compare

dom1 = lxml.etree.parse("doc1.xml").getroot()
dom2 = lxml.etree.parse("doc2.xml").getroot()
compare(dom1, dom2)

The two DOMs are modified in-place.

If you can’t install diff_match_patch_python, you can also get the pure-Python version of diff_match_patch.py from <https://code.google.com/p/google-diff-match-patch/source/browse/trunk/python3/diff_match_patch.py>. (The command-line tool will fall back to this library if it is available.)

Or you can pass in your own comparison library as the third argument. (See xml_diff/__init__.py’s default_differ function for how it would work.)

Release history Release notifications

History Node

0.7.0

This version
History Node

0.6.0

History Node

0.5.0

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
xml_diff-0.6.0.tar.gz (11.0 kB) Copy SHA256 hash SHA256 Source None Aug 13, 2014

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging CloudAMQP CloudAMQP RabbitMQ AWS AWS Cloud computing Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page