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%.