elmi/htmltreediff

Structure-aware diff for html and xml documents

HTML Tree Diff

Structure aware diff of XML and HTML documents.

The intended use is to concisely show the edits that have been made in a document, so that authors of html content can review their work.

What do we mean by "HTML Tree Diff"?

• HTML: The inputs to the diff function are HTML documents
• Tree: It considers the full XML tree structure of the inputs, not just text based changes.
• Diff: The output is human-readable HTML, using <ins> and <del> tags to show the changes.

Command line interface

You can execute htmltreediff.cli directly as a python module, passing it html files to diff:

$ python -m htmltreediff.cli one.html two.html
<h1>
  <del>
    one
  </del>
  <ins>
    two
  </ins>
</h1>

Python API

You can also use htmltreediff from within a python program as a library.

For HTML Changes:

>>> from htmltreediff import diff
>>> print diff('<h1>...one...</h1>', '<h1>...two...</h1>', pretty=True)
<h1>
  ...
  <del>
    one
  </del>
  <ins>
    two
  </ins>
  ...
</h1>

And also for text-only changes:

>>> print diff(
...     'The quick brown fox jumps over the lazy dog.',
...     'The very quick brown foxes jump over the dog.',
...     plaintext=False,
... )
The <ins>very </ins>quick brown <del>fox jumps</del><ins>foxes jump</ins> over the<del> lazy</del> dog.

Running the unit tests

The unit test suite requires the packages nose and coverage to run. Just run the run_tests.sh script, and all the tests will run, with code coverage. Code coverage should always be at 100%.