More versatile FileModal

[maxime-rainville]

The current FileLink modal is reusing the modal used to create WYSIWYG FileLink ... which doesn't allow more complex use case.

There could be a cool use case for providing a flexible Modal that allows you to pick a File and attach extra bit of MetaData to it. e.g. Select an image for a Slide in a carousel.

Basically any ManyMany relation between a file and another object with some metadata stored on the relation table could use this.

[maxime-rainville]

The InsertMediaModal is a component in AssetAdmin that allows to render the assets section in a Modal to select a file in various context. Each use case of this Modal is hard coded into it. The following use case are supported:

• Select a file in an UploadField
• Insert an image in a WYSIWIG
• Insert a link to a file in the WYSIWYG

The problem is that getting any other use case working would require us to hardcode them in asset-admin.

The SPIKE Identify opportunities to refactor InsertMediaModal identified some refactoring opportunities that could make the modal more flexible. The work highlighted in there would be a pre-requiste to getting this card working.

An alternative could be to take the same approach we ended up taking in LinkField v4: get the UploadField working in a Form Schema modal.

[maxime-rainville]

It's worth pointing that this could fulfill an old dream of mine: basically, allowing a dev to define some bit of metadata to attach to file when displaying it in context.

Example where this could be helpful:

• I want to have a list of banners with a call to action and a link
• I want to attach focus point to a specific instance of an image on a page

silverstripe/silverstripe-asset-admin#1021