Wagtail -扩展PageChooserBlock以支持外部URL

from wagtail.core.blocks import PageChooserBlock

class ExternalURLBlock(PageChooserBlock):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.field.widget.can_choose_root = False
        self.field.widget.can_choose_non_page = True

from wagtail.api import APIField

class ExternalURLBlock(PageChooserBlock):
    def get_api_representation(self, value, context=None):
        if value:
            return {
                'title': value,
                'url': value,
            }
        return None

    # ...

from wagtail.core.models import Page
from wagtail.core.fields import StreamField
from wagtail.admin.edit_handlers import FieldPanel
from wagtail.core import blocks

class MyPage(Page):
    body = StreamField([
        ('external_url', ExternalURLBlock()),
        # ...
    ])

    content_panels = Page.content_panels + [
        StreamFieldPanel('body'),
    ]