[#4396] Added the attributes retrival functionality

This is not the whole prefill plugin functionality. This commit handles
the procedures in order to be able to send to the frontend the available
attributes (for mapping the form variable with the objecttype attribute)
depending on the selected objecttype's version.

src/openapi.yaml

@@ -8537,6 +8537,8 @@ components:
 
             * `main` - Main
             * `authorizee` - Authorizee
+        prefillOptions:
+          $ref: '#/components/schemas/FormVariableOptions'
         dataType:
           allOf:
           - $ref: '#/components/schemas/DataTypeEnum'
@@ -8568,6 +8570,27 @@ components:
       - key
       - name
       - source
+    FormVariableOptions:
+      type: object
+      properties:
+        prefillPlugin:
+          type: string
+          description: The selected prefill plugin.
+        objectsApiGroup:
+          type: integer
+          description: Which Objects API group to use.
+        objecttypeUuid:
+          type: string
+          format: uuid
+          title: objecttype
+          description: 'UUID of the objecttype in the Objecttypes API. '
+        objecttypeVersion:
+          type: integer
+          description: Version of the objecttype in the Objecttypes API.
+        variablesMapping:
+          type: array
+          items:
+            $ref: '#/components/schemas/ObjecttypeVariableMapping'
     FormVersion:
       type: object
       properties:
@@ -9121,6 +9144,26 @@ components:
       - namePlural
       - url
       - uuid
+    ObjecttypeVariableMapping:
+      type: object
+      description: A mapping between a form variable key and the corresponding Objecttype
+        attribute.
+      properties:
+        variableKey:
+          type: string
+          description: The 'dotted' path to a form variable key. The format should
+            comply to how Formio handles nested component keys.
+          pattern: ^(\w|\w[\w.\-]*\w)$
+        targetPath:
+          type: array
+          items:
+            type: string
+            title: Segment of a JSON path
+          description: Representation of the JSON target location as a list of string
+            segments.
+      required:
+      - targetPath
+      - variableKey
     ObjecttypeVersion:
       type: object
       properties:
@@ -9627,19 +9670,6 @@ components:
       description: |-
         * `main` - Main
         * `authorizee` - Authorizee
-    PrefillObjectsAPIAttribute:
-      type: object
-      properties:
-        value:
-          type: string
-          title: ID
-          description: The unique attribute identifier
-        label:
-          type: string
-          description: The human-readable name for an attribute.
-      required:
-      - label
-      - value
     PrefillPlugin:
       type: object
       properties:

src/openforms/forms/admin/form_variable.py

@@ -18,6 +18,7 @@ class FormVariableAdmin(admin.ModelAdmin):
         "prefill_plugin",
         "prefill_attribute",
         "prefill_identifier_role",
+        "prefill_options",
         "data_type",
         "is_sensitive_data",
         "initial_value",
@@ -31,6 +32,7 @@ class FormVariableAdmin(admin.ModelAdmin):
         "prefill_plugin",
         "prefill_attribute",
         "prefill_identifier_role",
+        "prefill_options",
         "data_type",
         "data_format",
         "is_sensitive_data",

src/openforms/forms/api/serializers/form_variable.py

@@ -1,13 +1,21 @@
 from collections import defaultdict
 
+from django.db.models import Q
 from django.urls import reverse
 from django.utils.translation import gettext_lazy as _
 
+from drf_spectacular.utils import OpenApiExample, extend_schema_serializer
 from rest_framework import serializers
 from rest_framework.exceptions import ValidationError
 
-from openforms.api.fields import RelatedFieldFromContext
+from openforms.api.fields import (
+    PrimaryKeyRelatedAsChoicesField,
+    RelatedFieldFromContext,
+)
 from openforms.api.serializers import ListWithChildSerializer
+from openforms.formio.api.fields import FormioVariableKeyField
+from openforms.registrations.contrib.objects_api.models import ObjectsAPIGroupConfig
+from openforms.utils.mixins import JsonSchemaSerializerMixin
 from openforms.variables.api.serializers import ServiceFetchConfigurationSerializer
 from openforms.variables.constants import FormVariableSources
 from openforms.variables.models import ServiceFetchConfiguration
@@ -16,6 +24,67 @@
 from ...models import Form, FormDefinition, FormVariable
 
 
+@extend_schema_serializer(
+    examples=[
+        OpenApiExample(
+            name="Variable mapping example",
+            value={
+                "variable_key": "a_component_variable",
+                "target_path": ["path", "to.the", "target"],
+            },
+        )
+    ]
+)
+class ObjecttypeVariableMappingSerializer(serializers.Serializer):
+    """A mapping between a form variable key and the corresponding Objecttype attribute."""
+
+    variable_key = FormioVariableKeyField(
+        label=_("variable key"),
+        help_text=_(
+            "The 'dotted' path to a form variable key. The format should comply to how Formio handles nested component keys."
+        ),
+    )
+    target_path = serializers.ListField(
+        child=serializers.CharField(label=_("Segment of a JSON path")),
+        label=_("target path"),
+        help_text=_(
+            "Representation of the JSON target location as a list of string segments."
+        ),
+    )
+
+
+class FormVariableOptionsSerializer(JsonSchemaSerializerMixin, serializers.Serializer):
+    prefill_plugin = serializers.CharField(
+        required=False, help_text=_("The selected prefill plugin.")
+    )
+    objects_api_group = PrimaryKeyRelatedAsChoicesField(
+        queryset=ObjectsAPIGroupConfig.objects.exclude(
+            Q(objects_service=None)
+            | Q(objecttypes_service=None)
+            | Q(drc_service=None)
+            | Q(catalogi_service=None)
+        ),
+        label=("Objects API group"),
+        required=False,
+        help_text=_("Which Objects API group to use."),
+    )
+    objecttype_uuid = serializers.UUIDField(
+        label=_("objecttype"),
+        required=False,
+        help_text=_("UUID of the objecttype in the Objecttypes API. "),
+    )
+    objecttype_version = serializers.IntegerField(
+        label=_("objecttype version"),
+        required=False,
+        help_text=_("Version of the objecttype in the Objecttypes API."),
+    )
+    variables_mapping = ObjecttypeVariableMappingSerializer(
+        label=_("variables mapping"),
+        many=True,
+        required=False,
+    )
+
+
 class FormVariableListSerializer(ListWithChildSerializer):
     def get_child_serializer_class(self):
         return FormVariableSerializer
@@ -110,6 +179,7 @@ class FormVariableSerializer(serializers.HyperlinkedModelSerializer):
     service_fetch_configuration = ServiceFetchConfigurationSerializer(
         required=False, allow_null=True
     )
+    prefill_options = FormVariableOptionsSerializer(required=False)
 
     class Meta:
         model = FormVariable
@@ -124,6 +194,7 @@ class Meta:
             "prefill_plugin",
             "prefill_attribute",
             "prefill_identifier_role",
+            "prefill_options",
             "data_type",
             "data_format",
             "is_sensitive_data",

src/openforms/forms/api/typing.py

@@ -0,0 +1,20 @@
+from typing import TYPE_CHECKING, Required, TypedDict
+
+if TYPE_CHECKING:
+    from openforms.registrations.contrib.objects_api.models import ObjectsAPIGroupConfig
+
+
+class _BasePrefillOptions(TypedDict):
+    prefill_plugin: str
+
+
+class ObjecttypeVariableMapping(TypedDict):
+    variable_key: str
+    target_path: list[str]
+
+
+class ObjectsAPIPrefillOptions(_BasePrefillOptions):
+    objects_api_group: Required[ObjectsAPIGroupConfig]
+    objecttype_uuid: Required[str]
+    objecttype_version: Required[int]
+    variables_mapping: Required[list[ObjecttypeVariableMapping]]

src/openforms/forms/migrations/0098_formvariable_prefill_options.py

@@ -0,0 +1,20 @@
+# Generated by Django 4.2.15 on 2024-08-21 11:04
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("forms", "0097_v267_to_v270"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="formvariable",
+            name="prefill_options",
+            field=models.JSONField(
+                blank=True, default=dict, verbose_name="prefill options"
+            ),
+        ),
+    ]

src/openforms/forms/models/form_variable.py

@@ -161,6 +161,11 @@ class FormVariable(models.Model):
         default=IdentifierRoles.main,
         max_length=100,
     )
+    prefill_options = models.JSONField(
+        _("prefill options"),
+        default=dict,
+        blank=True,
+    )
     data_type = models.CharField(
         verbose_name=_("data type"),
         help_text=_("The type of the value that will be associated with this variable"),

src/openforms/prefill/api/serializers.py

@@ -64,14 +64,3 @@ class PrefillAttributeSerializer(serializers.Serializer):
         label=_("Label"),
         help_text=_("The human-readable name for an attribute."),
     )
-
-
-class PrefillObjectsAPIAttributeSerializer(serializers.Serializer):
-    value = serializers.CharField(
-        label=_("ID"),
-        help_text=_("The unique attribute identifier"),
-    )
-    label = serializers.CharField(
-        label=_("Label"),
-        help_text=_("The human-readable name for an attribute."),
-    )

src/openforms/prefill/contrib/objects_api/plugin.py

@@ -10,6 +10,7 @@
 from ...base import BasePlugin
 from ...constants import IdentifierRoles
 from ...registry import register
+from .utils import retrieve_properties
 
 logger = logging.getLogger(__name__)
 
@@ -25,7 +26,8 @@ class ObjectsAPIPrefill(BasePlugin):
     def get_available_attributes(
         reference: dict[str, Any] | None = None,
     ) -> Iterable[tuple[str, str]]:
-        pass
+        assert reference is not None
+        return retrieve_properties(reference)
 
     @classmethod
     def get_prefill_values(
@@ -41,3 +43,6 @@ def get_co_sign_values(
         cls, submission: Submission, identifier: str
     ) -> tuple[dict[str, Any], str]:
         pass
+
+    def check_config(self):
+        pass

src/openforms/prefill/contrib/objects_api/tests/files/vcr_cassettes/ObjectsAPIPrefillPluginTests/ObjectsAPIPrefillPluginTests.test_available_attributes.yaml

@@ -0,0 +1,46 @@
+interactions:
+- request:
+    body: null
+    headers:
+      Accept:
+      - '*/*'
+      Accept-Encoding:
+      - gzip, deflate, br
+      Authorization:
+      - Token 171be5abaf41e7856b423ad513df1ef8f867ff48
+      Connection:
+      - keep-alive
+      User-Agent:
+      - python-requests/2.32.2
+    method: GET
+    uri: http://localhost:8001/api/v2/objecttypes/8e46e0a5-b1b4-449b-b9e9-fa3cea655f48/versions/3
+  response:
+    body:
+      string: '{"url":"http://objecttypes-web:8000/api/v2/objecttypes/8e46e0a5-b1b4-449b-b9e9-fa3cea655f48/versions/3","version":3,"objectType":"http://objecttypes-web:8000/api/v2/objecttypes/8e46e0a5-b1b4-449b-b9e9-fa3cea655f48","status":"draft","jsonSchema":{"$id":"https://example.com/person.schema.json","type":"object","title":"Person","$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"age":{"type":"integer","minimum":18},"name":{"type":"object","properties":{"last.name":{"type":"string"}}},"nested":{"type":"object","properties":{"unrelated":{"type":"string"},"submission_payment_amount":{"type":"number","multipleOf":0.01}}},"submission_date":{"type":"string","format":"date-time"},"submission_csv_url":{"type":"string","format":"uri"},"submission_pdf_url":{"type":"string","format":"uri"},"submission_payment_completed":{"type":"boolean"},"submission_payment_public_ids":{"type":"array"}}},"createdAt":"2024-02-08","modifiedAt":"2024-02-08","publishedAt":"2024-02-08"}'
+    headers:
+      Allow:
+      - GET, PUT, PATCH, DELETE, HEAD, OPTIONS
+      Connection:
+      - keep-alive
+      Content-Length:
+      - '985'
+      Content-Type:
+      - application/json
+      Cross-Origin-Opener-Policy:
+      - same-origin
+      Date:
+      - Wed, 28 Aug 2024 08:04:23 GMT
+      Referrer-Policy:
+      - same-origin
+      Server:
+      - nginx/1.27.0
+      Vary:
+      - origin
+      X-Content-Type-Options:
+      - nosniff
+      X-Frame-Options:
+      - DENY
+    status:
+      code: 200
+      message: OK
+version: 1