Feature Request: Live Fields

[mhnbcu]

I'm anticipating a potential need for our editors that I can only naively describe off-hand as "live fields".

This can be summed up as the capability to have a dependent field or widget of the administration user interface change value automatically (without saving) in response to a value change in another field.

For example, our editors will need the ability to specify the "type of shot" a photo is on upload. Having the focal point on the image update the focal point preview rectangle automatically would ease the workflow and add confidence in the intended result for the editor prior to saving. Note: If Celery and queued feature detection is enabled then a "barber pole progress bar" or something similar could display until the job is complete.

Another example would be if a user changed a "Country" field on a Location page. Then perhaps a field named "Region" could automatically dump its value and refresh with a select list of relevant regions for the newly selected country.

This seems like it would be a large undertaking if it is value to the project.

What do you think about this feature request?

[davecranwell]

We've discussed this before and it was originally tabled early 2014 as something that a proposed ground-up refactor of the edit handler system might address.

#161 and #381 both touch on it.

In the event however we moved tangentially towards developing StreamField. It's still an idea we're interested in but it's just a question of priorities.

[mhnbcu]

@davecranwell thank you for the quick response!

The CalculatedFieldPanel concept mentioned by @kaedroho in #161 (comment) looks promising. The need in #381 has some similarity to the first example outlined in the opening comment in this issue.

Perhaps a good abstraction project, one without an official API initially, could help scope the work?

Being able to specify what feature detection to use for an image seems like a good candidate. Such a capability could provide customization options for field name and labels to cascade mapping in the Image model. See example in wagtail/Willow#5 (comment)

Then the scope would mainly be determining the mechanism to refresh the image focal point. Whatever the mechanism for the feature could have its API worked out over a couple of minor releases.

I fully understand the prioritization component to all this. Having this capability, like Streamfield, would [be one more capability that] really sets Wagtail apart.

[thibaudcolas]

👋 I believe this has been implemented as part of the Stimulus adoption, and #10133. We now have a way to do client-side extensions of this type to have inter-dependent UI components, and for fields specifically, a way to attach client-side behavior to a single field.