RelationList Widget

[arky]

If your content type uses 'Relation List' then there a not usable since there is dedicated widget to handle this type. I think current placeholder refers to Object Browser Widget. I think Relation Choice might also suffer from limited functionality.

Is your feature request related to a problem? Please describe.
This lack of widget makes selection and adding of relations in Volto impossible.

Describe the solution you'd like
Add a new widget based on existing volto list widgets.

volto/src/config/Widgets.jsx

Lines 76 to 79 in d1ebf8c

	factory: {
	'Relation List': ObjectBrowserWidget,
	'Relation Choice': ReferenceWidget,
	},

[arky]

There is some work done by @nileshgulia1 in this source tree https://github.com/plone/volto/tree/relations-volto

Some work needs to be done based on new plone.restapi endpoint @relations https://github.com/plone/plone.restapi/tree/relations-documentation-etc

[arky]

@ksuess @nileshgulia1 This bug is quite critical to enable users to select and add relations in Volto. It is my understanding that the blocker in plone.restapi has now been resolved by new proposal by @pbauer https://github.com/plone/plone.restapi/tree/relations-documentation-etc

Really appreciate your continue support and contributions in making relations work out of box in Volto! Thank you.

[nileshgulia1]

Katja drafted a PR for relations controlpanel: #3382

[ksuess]

A bug fix is needed to feed the ObjectBrowserWidget with the vocabulary of the field.
This is not related to a @relations endpoint.
This bug fix could also be accompanied with a replacement of the widget for the RelationChoice field by ObjectBrowserWidget (single mode).

[ericof]

So, it seems there is a simple way to make this work as expected. Passing pattern_options and frontendOptions via directives.widget turns the current ObjectBrowserWidget more friendly to relations.

Take a look at the implementation bellow

from plone.autoform import directives
from z3c.relationfield.schema import RelationChoice
from z3c.relationfield.schema import RelationList
from plone.app.z3cform.widget import RelatedItemsFieldWidget

...

    campus2 = RelationList(
        title=_("person_campus", default="Campus"),
        required=False,
        default=list(),
        value_type=RelationChoice(
            title=_("person_campus", default="Campus"),
            vocabulary="plone.app.vocabularies.Catalog",
        ),
    )
    directives.widget(
        "campus",
        RelatedItemsFieldWidget,
        pattern_options={
            "selectableTypes": ['campus']
        },
        frontendOptions={
            "widget": "object_browser",
            "widgetProps": {"mode": "multiple", "return": "multiple"},
        },
    )

To be honest, the only thing I would like to have more was a way to pass a start point for the ObjectBrowserWidget start the search tree.

@arky, @ksuess, @nileshgulia1, what do you think?

[ksuess]

Unfortunatly this does not work for me:

• No selection possible on new document in Volto
• No display of related items in Volto on document with related items selected in backend.

I think ObjectBrowserWidget needs some attention.

• bug fix: this.props.mode === 'multiple' ? [...(this.props.value || [])] : [];
• bug fix for the return value on 'multiple'

BTW your frontendOptions is the default for factory Relation List which is the case for RelatedItemsFieldWidget

[ksuess]

Also still open:

• Support for StaticCatalogVocabulary

[sneridagh]

@arky added to the 16 Milestone.

[arky]

Thank you @sneridagh for including this in the release milestone.The ability to add multiple relationships in Volto would make relations first class citizen in Plone 6.

[sneridagh]

@arky I think this is solved already thanks to the work done in #4614 Please feel free to re-open if it's not the case.

[arky]

Thank you! \o/

[ksuess]

See documentation: https://docs.plone.org/volto/recipes/widget.html#relation-fields