Wagtail Grapple

You can attach additional GraphQL interfaces to Wagtail Pages, Django models, or StreamField blocks by defining the graphql_interfaces attribute. This attribute accepts a list or a tuple of interface classes. These interfaces will be appended to the base interfaces already provided by Grapple.

Implementation Examples

For a Wagtail Page model:

from wagtail.models import Page
from .interfaces import MyInterface

class MyPage(Page):
    graphql_interfaces = (MyInterface,)

For a standard Django model:

from django.db import models
from .interfaces import MyInterface

class MyModel(models.Model):
    graphql_interfaces = (MyInterface,)

For a StreamField block:

from wagtail.core import blocks
from .interfaces import MyInterface

class MyStructBlock(blocks.StructBlock):
    graphql_interfaces = (MyInterface,)

# Example interface definition
class MyInterface(graphene.Interface):
    custom_field = graphene.String()

# Adding to a Page model
class MyPage(Page):
    graphql_interfaces = (MyInterface,)

Grapple automatically builds GraphQL types by iterating over your project's models. To expose specific fields via GraphQL, add a graphql_fields attribute to your Wagtail model. This attribute should be a list of Grapple-specific field types (like GraphQLString, GraphQLRichText, or GraphQLStreamfield) that map to your model's existing fields.

When you define graphql_fields, the structure of the resulting GraphQL type is determined by the list you provide. For example, a StreamField in Wagtail can be exposed using GraphQLStreamfield to allow querying its block structure and raw values in GraphQL.

from django.db import models
from grapple.models import GraphQLRichText, GraphQLStreamfield, GraphQLString
from wagtail import blocks
from wagtail.models import Page
from wagtail.images.blocks import ImageBlock
from wagtail.fields import RichTextField, StreamField
from wagtail.admin.edit_handlers import FieldPanel

class BlogPage(Page):
    author = models.CharField(max_length=255)
    date = models.DateField("Post date")
    summary = RichTextField()
    body = StreamField(
        [
            ("heading", blocks.CharBlock(classname="full title")),
            ("paragraph", blocks.RichTextBlock()),
            ("image", ImageBlock()),
        ]
    )

    content_panels = Page.content_panels + [
        FieldPanel("author"),
        FieldPanel("date"),
        FieldPanel("summary"),
        FieldPanel("body"),
    ]

    # Define which fields are exposed to GraphQL
    graphql_fields = [
        GraphQLString("heading"),
        GraphQLString("date"),
        GraphQLString("author"),
        GraphQLRichText("summary"),
        GraphQLStreamfield("body"),
    ]

To enable Grapple, you must perform three configuration steps in your Django settings and URL configuration:

1. Add to INSTALLED_APPS: Include "grapple" and "graphene_django" in your INSTALLED_APPS list.
2. Configure Grapple and Graphene:
   • Set GRAPHENE = {"SCHEMA": "grapple.schema.schema"} to point to the Grapple schema.
   • Set GRAPPLE = {"APPS": ["app_name"]} where "app_name" is the list of Django apps you want Grapple to scan for models to generate GraphQL types.
3. Register GraphQL URLs: Include grapple_urls in your urlpatterns in urls.py.

# settings.py
INSTALLED_APPS = [
    # ...
    "grapple",
    "graphene_django",
    # ...
]

# Grapple Config:
GRAPHENE = {"SCHEMA": "grapple.schema.schema"}
GRAPPLE = {
    "APPS": ["home"],
}

# urls.py
from django.urls import path, include
from grapple import urls as grapple_urls

urlpatterns = [
    # ...
    path("", include(grapple_urls)),
    # ...
]