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LiquidBT Plugins

LiquidBT plugins are classes that extend or modify functionality of LiquidBT.

Use a Plugin

To use a plugin, you need to:

  1. Import it at the top of your LiquidBT configuration file.
  2. Create an instance of the plugin's class in the plugins list that you pass to liquidbt.main.
  3. The plugin will be loaded!

Make a Plugin

Making a plugin is simple.

  1. Create a new Python package following the naming scheme liquidbt_plugin_pluginname.
  2. In your, add this import:
    from liquidbt.plugins import Plugin
  3. Add a class with the name of your plugin that extends the forementioned Plugin class. In this class, you can override any of the mentioned fields in the up-to-date API reference.
  4. Instruct your users to import and use your plugin. Easy as that.

By default, plugins only can add, but using the build plugin, you can change functionality. See Transformer Plugins.

Transformer Plugins

A transformer plugin is a plugin that can change the code (not the source, the code that is compiled by setuptools).

To make a transformer, your plugin must extend a different class then typical plugins:

from liquidbt.plugins import TransformerPlugin

class MyPlugin(TransformerPlugin):
    # ...

Class Inheritence

The TransformerPlugin class extends the plugin class, so any functions you can add to Plugins can also be added to TransformerPlugins.

To actually change the code, you will need to add the process_code(code: str) -> str method to the class. This method accepts the parameter code, which is a multiline string of the current file being evaluated's contents. It must return the changed version of the code (also a multiline string).

Avoiding Transformation

If you don't need to modify the file's contents, (for example if you make a plugin that comments out all code (bear with me here), and you want to skip certain files) you can just return the code parameter, which will ensure that your plugin doesn't change anything. But do not return None or something like it, as the file's code will be composed of what you returned.

Dangers of Creating Transformer Plugins

While the TransformerPlugin class API is in LiquidBT's core package, it isn't actually implemented there (other then checking if any of the plugins are transformers, to prevent potential issues). The build plugin must be loaded before any transformers, otherwise errors will be thrown. This means instructing users to put the build plugin first in the plugin list.

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