Best practices for add-ons
Best practices for add-ons#
Although the add-on framework is relatively new in Volto's world, there are quite a few generic add-ons that can be used in any Volto project.
Based on the experience gained developing some of these add-ons, we recommend that you follow (no need for strictness, of course) these rough guidelines:
Integrate your add-on with Volto's add-on framework#
Just like Plone add-ons provide some features by default, Volto add-ons should register some features by default. For example, if your add-on provides widgets, register the most basic configuration of that widget with a name that can be used.
On more complicated cases, see if you can structure your code to use the
settings configuration registry, or stash your configuration in your block
registration, for example.
As an example: let's say we're building a Color Picker widget and we want to
provide a palette of colors from which to choose. The widget should integrate
with a default
settings.colorWidgetPalette, which would be a list of colors.
And of course, also provide a widget factory so it can be used to create multiple instances of that color widget with custom color palettes.
Provide additional configuration#
An add-on can ship with multiple Volto configuration loaders. This makes it possible to provide configuration methods for demo purposes, for example, or to ship with a default "shallow" integration, then provide another separate configuration loader for a deeper integration.
Avoid shadowing Volto files#
This rule is meant to be broken. If you find that you need to customize a particular file from Volto and you have multiple projects, better to create an add-on that holds that customized file, so that you have a single place to maintain that "file fork", but otherwise it's a good idea to avoid shipping generic add-ons with Volto customizations. Make sure to include this information as a warning in your add-on description!
See if your use case is generic enough, maybe Volto needs to be extended to cover that use case, directly in core.
Deadlines can be rough and documentation tends to be pushed as last priority, but please add a minimal Readme with a couple of lines and, most importantly, a screenshot.
Ideally, the Readme should also include install instructions and details on any possible settings.
Testing the add-on#
It is not easy, right now, to ship an add-on with a self-bootstraping and testing framework. But you can create a separate minimal Volto project that can hold the Cypress integration tests and trigger the CI tests.
Even if you think your add-on is not generic or it's tricky to integrate, please
consider including your add-on in the
list. This provides visibility to your add-on but also further solidifies
Volto's possition in our Plone community.