Create fields for structural block types

I want to make a field that’s a simple list downloads. The following code accomplishes what I want using StreamField, but the API is a little weird.

class ResourcesPage(Page):
    files = StreamField([
        ('files', DocumentChooserBlock())
    ])

Ideally it would look something like this:

class ResourcesPage(Page):
    files = ListField(DocumentChooserBlock())

Here I’ve created a new imaginary type, ListField. There are a few possible solutions (such changing the way StreamField parameters work) but I think it makes sense to have a wrapper field around each of the structural block types.

Here’s an example of how an implementation could look:

from wagtail.wagtailcore.fields import StructField, ListField, StreamField
from wagtail.wagtaildocs.blocks import DocumentChooserBlock
from wagtail.wagtailimages.blocks import ImageChooserBlock
from wagtail.wagtailcore import blocks


class RecipePage(Page):
    # StructBlock wrapper
    chef = StructField([
        ('first_name', blocks.CharBlock(required=True)),
        ('surname', blocks.CharBlock(required=True)),
        ('photo', ImageChooserBlock()),
        ('biography', blocks.RichTextBlock())
    ])

    # ListBlock wrapper
    ingredients_list = ListField(blocks.CharBlock(label="Ingredient"))

    # StreamBlock (just a regular StreamField)
    instructions = StreamField([
        ('paragraph', blocks.RichTextBlock(icon="pilcrow")),
        ('h1', blocks.CharBlock(classname="title", icon="title"))
    ])

This could also help us determine how the fields should appear in the admin (example: #1549)

[gasman]

The core team has discussed this today, and we’re happy with the principle of adding ListField / StructField types in parallel with StreamField (or, perhaps more simply, allowing StreamField to accept ListBlock / StructBlock as the top-level block).

[ddiazpinto]

In my opinion, the best approach is to have an specific field for each structural block type:

• StructField for StructBlock
• ListField for ListBlock
• StreamField for StreamBlock

Regarding to the wagtail admin views:

• StructField wouldn’t need to include a “new” button, just render the block form.
• ListField wouldn’t need to show the stream menu to choose the model to add.
• StreamField would work as usual

Of course ListField could be considered just a particular case of StreamField and be omitted, but if ListBlock exists, I think ListField should exists too.