Public Python API¶
Flake8 3.0.0 presently does not have a public, stable Python API.
When it does it will be located in
flake8.api and that will
be documented here.
When Flake8 broke its hard dependency on the tricky internals of
pycodestyle, it lost the easy backwards compatibility as well. To help
existing users of that API we have
flake8.api.legacy. This module
includes a couple classes (which are documented below) and a function.
The main usage that the developers of Flake8 observed was using the
get_style_guide() function and then calling
check_files(). To a lesser extent,
people also seemed to use the
method on what
check_files returns. We then sought to preserve that
API in this module.
Let’s look at an example piece of code together:
from flake8.api import legacy as flake8 style_guide = flake8.get_style_guide(ignore=['E24', 'W503']) report = style_guide.check_files([...]) assert report.get_statistics('E') == , 'Flake8 found violations'
This represents the basic universal usage of all existing Flake8 2.x integrations. Each example we found was obviously slightly different, but this is kind of the gist, so let’s walk through this.
Everything that is backwards compatible for our API is in the
flake8.api.legacy submodule. This is to indicate, clearly, that
the old API is being used.
We create a
flake8.api.legacy.StyleGuide by calling
flake8.api.legacy.get_style_guide(). We can pass options
flake8.api.legacy.get_style_guide() that correspond to the command-line options one might use.
For example, we can pass
Our legacy API, does not enforce legacy behaviour, so we can combine
select like we might on the command-line, e.g.,
style_guide = flake8.get_style_guide( ignore=['E24', 'W5'], select=['E', 'W', 'F'], format='pylint', )
Once we have our
flake8.api.legacy.StyleGuide we can use the same methods that we used before,
These are not perfectly backwards compatible. Not all arguments are respected, and some of the types necessary for something to work have changed.
Most people, we observed, were using
check_files(). You can use this to specify
a list of filenames or directories to check. In Flake8 3.0, however, we
return a different object that has similar methods. We return a
has the method
Most usage of this method that we noted was as documented above. Keep in mind, however, that it provides a list of strings and not anything more malleable.