Ability to filter image caption

[kallehauge]

Is your feature request related to a problem? Please describe.
I would like to be able to alter the caption text on the initial insert of an image (default image block), like it is possible with ex image_add_caption_text in the classic WYSIWYG editor.

(I guess this could be expanded to alter things like alt attribute text etc as well?)

Describe the solution you'd like
I would like a filter or some sort of option to alter and/or override the caption text.
The way it works right now with Gutenberg, if I understand it correctly, then the Media window is loaded with the image and their metadata "on demand" and if one or multiple images are selected then they will get injected directly into the editor, so there is no place to change this before insertion. So the only potential option would be to change the values already when the window is opened but this surely seems like a bad workaround.

What would be really ideal from a plugin/theme developers perspective would be to get access to the data here:

gutenberg/edit-post/hooks/blocks/media-upload/index.js

Line 177 in be346ba

return ! mediaObject.caption ?

[draganescu]

@youknowriad this issue has been added to the Extensibility project which I see you've closed. Should we remove issues that are still relevant from closed projects?

[youknowriad]

Yes, we can remove the project assignment, it's not that important though. Other closed project assignments might be important to keep track of though (other than Extensibilty)

[vreemt]

it might be good to add this to #28923 and possibly get a progress update please & thank you

[jordesign]

@kallehauge Does the fact that the caption tool is available in the toolbar resolve this for you? Or is this still something to keep in mind?

[kallehauge]

Uh! It's been a while @jordesign, but I believe I had a few different instances where dynamically defining the caption during insert made sense (there might be different workarounds for some of them, now).

• I believe one of them was translation related, so if different translations was stored as metadata on the attachment, it wasn't possible to change the string that's being used.
• Another instance I vaguely remember is inserting copyright information (either the attachment owner or a metadata value).

TL;DR: I believe it's still as valid for the same use-cases that the older classic editor image_add_caption_text filter satisfies (automating work for the editor and allowing 3. parties to generally modify the value)

[jordesign]

Thanks for checking in @kallehauge - given all that it makes sense to leave it open for now 👍