Guidelines for Code Modification

Coding Style

Use syntax compatible with Python 2.6+ and 3.1+.
Use docstrings with pydoc in mind
Follow the PEP8 style guide: https://www.python.org/dev/peps/pep-0008/
Always run make test before submitting a new PR. pylint, flake8, pytest, doctest and shellcheck need to be installed. (If you don't change any shell scripts you can run make test_py and you don't need the shellcheck dependency but it's an awesome tool, so check it out : )
When breaking backward compatibility with old configuration files or plugins, please include a temporary workaround code that provides a compatibility layer and mark it with a comment that includes the word COMPAT. For examples, grep the code for the word COMPAT. :)

Patches

Send patches, created with git format-patch, to the email address

[email protected]

or open a pull request on GitHub.

Please use PGP-encryption for security-relevant patches or messages. PGP key IDs are shared along with releases on https://ranger.fm and can be attempted in reverse chronological order in case a maintainer is unresponsive.

Version Numbering

Three numbers, A.B.C, where

A changes on a rewrite
B changes when major configuration incompatibilities occur
C changes with each release

Starting Points

Good places to read about ranger internals are:

ranger/core/actions.py
ranger/container/fsobject.py

About the UI:

ranger/gui/widgets/browsercolumn.py
ranger/gui/widgets/view_miller.py
ranger/gui/ui.py

Common Changes

Adding options

Add a default value in rc.conf, along with a comment that describes the option.
Add the option to the ALLOWED_SETTINGS dictionary in the file ranger/container/settings.py in alphabetical order.
Add an entry in the man page by editing doc/ranger.pod, then rebuild the man page by running make man in the ranger root directory

The setting is now accessible with self.settings.my_option, assuming self is a subclass of ranger.core.shared.SettingsAware.

Adding colorschemes

Copy ranger/colorschemes/default.py to ranger/colorschemes/myscheme.py and modify it according to your needs. Alternatively, create a subclass of ranger.colorschemes.default.Default and override the use method, as it is done in the Jungle colorscheme.
Add this line to your ~/.config/ranger/rc.conf: set colorscheme myscheme

Change which programs start which file types

Edit the configuration file ~/.config/ranger/rifle.conf. The default one can be obtained by running ranger --copy-config rifle.

Change which file extensions have which mime type

Modify ranger/data/mime.types. You may also add your own entries to ~/.mime.types

Change which files are previewed in the auto preview

In ranger/container/file.py, change the constant PREVIEW_BLACKLIST

HACKING