🎩 What? Why?

This PR replaces CarrierWave attachments with ActiveStorage:

• The namespace isolation of each module engine doesn't give us access to the methods to generate the urls provided by AS. The inclusion of these methods in each engine causes a drop performance (the duration of tests are doubled) so I've added all paths methods to the base uploader class. The HasUploadValidations concern adds an instance method to the classes to access the url helper methods:

For example:

user.avatar.url

changes to

user.attached_uploader(:avatar).path

CarrierWave also has a system of versions to define different sizes of images, for example. ActiveStorage has something similar, variants, but does not admit named variants by default. I've moved the CarrierWave versions definitions to a hash in the uploaders which can be used to generate named variants:

For example

user.avatar.big.url

changes to:

user.attached_uploader(:avatar).path(variant: :big) or user.attached_uploader(:avatar).variant_path(:big)

Other methods are available to generate full URLs:

user.attached_uploader(:avatar).url(host: user.organization.host)
user.attached_uploader(:avatar).url(variant: :big, host: user.organization.host)
user.attached_uploader(:avatar).variant_url(:big, host: user.organization.host)

• This PR removes inheritance of application uploaders from CarrierWave and implements some logic provided by it. For example CarrierWave uploaders define their own processors to perform some validations. These validations has been moved to extenal validators:
  • OrganizationPresentValidator Checks the presence of an organization in the instance of the model. This is important because some configurations for the validations are defined in the organization
  • UploaderImageDimensionsValidator Checks dimension of the images and compares them with the maximum values set in the upoader

Other relevant changes of this PR:

• Transforms the upload form builder method to work with ActiveStorage attributes: With CarrierWave when the attachment attributes were called the application returned a CarrierWave uploader, while with ActiveStorage an instance of ActiveStorage::Attached::One is returned. With attached_uploader we can access to the logic provided by the uploader. This has been used to change upload builder method which generates different output depending on the uploader configuration.
• Removes some not null constraints on columns used by CarrierWave In a future PR these columns should be removed completely (see Plan migration of existing CarrierWave attachments to ActiveStorage #7796)
• Changes seeds to generate ActiveStorage attachments
• Implements remote_url= method provided by CarrierWave to attach a file from a URL in Decidim::ApplicationUploader
• Changes content blocks attachments by defining a new Decidim::ContentBlockAttachment model which stores the name of each attachment defined in the content block manifest to use the correspoding uploader (see Migrate content block images to ActiveStorage #7739)

📌 Related Issues

Link your PR to an issue

• Related to Plan migration of existing CarrierWave attachments to ActiveStorage #7796
• Fixes Migrate from Carrierwave to ActiveStorage #7290
• Fixes Migrate content block images to ActiveStorage #7739

Testing

The interface behavior should be the same as before this PR

📋 Checklist

🚨 Please review the guidelines for contributing to this repository.

• ❓ CONSIDER adding a unit test if your PR resolves an issue.
• ✔️ DO check open PR's to avoid duplicates.
• ✔️ DO keep pull requests small so they can be easily reviewed.
• ✔️ DO build locally before pushing.
• ✔️ DO make sure tests pass.
• ✔️ DO make sure any new changes are documented in docs/.
• ✔️ DO add and modify seeds if necessary.
• ✔️ DO add CHANGELOG upgrade notes if required.
• ✔️ DO add to GraphQL API if there are new public fields.
• ✔️ DO add link to MetaDecidim if it's a new feature.
• ❌AVOID breaking the continuous integration build.
• ❌AVOID making significant changes to the overall architecture.

📷 Screenshots

Please add screenshots of the changes you're proposing

♥️ Thank you!