feat: Add support for Django models (#101)

Issue #39: #39
PR #101: #101

Author: mRokita

Diff for: pyproject.toml

@@ -59,6 +59,7 @@ toml = "^0.10.2"
 wemake-python-styleguide = "^0.14.1"
 pydantic = "^1.8.1"
 marshmallow = "^3.11.1"
+Django = "^3.2"
 
 [tool.poetry.scripts]
 pytkdocs = "pytkdocs.cli:main"

Diff for: src/pytkdocs/loader.py

@@ -12,8 +12,9 @@
 import warnings
 from functools import lru_cache
 from itertools import chain
+from operator import attrgetter
 from pathlib import Path
-from typing import Any, Dict, List, Optional, Set, Union
+from typing import Any, Dict, List, Mapping, Optional, Set, Tuple, Union
 
 from pytkdocs.objects import Attribute, Class, Function, Method, Module, Object, Source
 from pytkdocs.parsers.attributes import get_class_attributes, get_instance_attributes, get_module_attributes, merge
@@ -508,6 +509,7 @@ def get_class_documentation(self, node: ObjectNode, select_members=None) -> Clas
         for attr_name, properties, add_method in (
             ("__fields__", ["pydantic-model"], self.get_pydantic_field_documentation),
             ("_declared_fields", ["marshmallow-model"], self.get_marshmallow_field_documentation),
+            ("_meta.get_fields", ["django-model"], self.get_django_field_documentation),
             ("__dataclass_fields__", ["dataclass"], self.get_annotated_dataclass_field),
         ):
             if self.detect_field_model(attr_name, direct_members, all_members):
@@ -530,14 +532,24 @@ def detect_field_model(self, attr_name: str, direct_members, all_members) -> boo
         Detect if an attribute is present in members.
 
         Arguments:
-            attr_name: The name of the attribute to detect.
+            attr_name: The name of the attribute to detect, can contain dots.
             direct_members: The direct members of the class.
             all_members: All members of the class.
 
         Returns:
             Whether the attribute is present.
         """
-        return attr_name in direct_members or (self.select_inherited_members and attr_name in all_members)
+
+        first_order_attr_name, remainder = split_attr_name(attr_name)
+        if not (
+            first_order_attr_name in direct_members
+            or (self.select_inherited_members and first_order_attr_name in all_members)
+        ):
+            return False
+
+        if remainder and not attrgetter(remainder)(all_members[first_order_attr_name]):
+            return False
+        return True
 
     def add_fields(
         self,
@@ -561,7 +573,10 @@ def add_fields(
             base_class: The class declaring the fields.
             add_method: The method to add the children object.
         """
-        for field_name, field in members[attr_name].items():
+
+        fields = get_fields(attr_name, members=members)
+
+        for field_name, field in fields.items():
             select_field = self.select(field_name, select_members)  # type: ignore
             is_inherited = field_is_inherited(field_name, attr_name, base_class)
 
@@ -683,6 +698,35 @@ def get_pydantic_field_documentation(node: ObjectNode) -> Attribute:
             properties=properties,
         )
 
+    @staticmethod
+    def get_django_field_documentation(node: ObjectNode) -> Attribute:
+        """
+        Get the documentation for a Django Field.
+
+        Arguments:
+            node: The node representing the Field and its parents.
+
+        Returns:
+            The documented attribute object.
+        """
+        prop = node.obj
+        path = node.dotted_path
+        properties = ["django-field"]
+
+        if prop.null:
+            properties.append("nullable")
+        if prop.blank:
+            properties.append("blank")
+
+        return Attribute(
+            name=node.name,
+            path=path,
+            file_path=node.file_path,
+            docstring=prop.verbose_name,
+            attr_type=prop.__class__,
+            properties=properties,
+        )
+
     @staticmethod
     def get_marshmallow_field_documentation(node: ObjectNode) -> Attribute:
         """
@@ -913,3 +957,39 @@ def field_is_inherited(field_name: str, fields_name: str, base_class: type) -> b
             *(getattr(parent_class, fields_name, {}).keys() for parent_class in base_class.__mro__[1:-1]),
         ),
     )
+
+
+def split_attr_name(attr_name: str) -> Tuple[str, Optional[str]]:
+    """
+    Split an attribute name into a first-order attribute name and remainder.
+
+    Args:
+        attr_name: Attribute name (a)
+
+    Returns:
+        Tuple containing:
+            first_order_attr_name: Name of the first order attribute (a)
+            remainder: The remainder (b.c)
+
+    """
+    first_order_attr_name, *remaining = attr_name.split(".", maxsplit=1)
+    remainder = remaining[0] if remaining else None
+    return first_order_attr_name, remainder
+
+
+def get_fields(attr_name: str, *, members: Mapping[str, Any] = None, class_obj=None) -> Dict[str, Any]:
+    if not (bool(members) ^ bool(class_obj)):
+        raise ValueError("Either members or class_obj is required.")
+    first_order_attr_name, remainder = split_attr_name(attr_name)
+    fields = members[first_order_attr_name] if members else dict(vars(class_obj)).get(first_order_attr_name, {})
+    if remainder:
+        fields = attrgetter(remainder)(fields)
+
+    if callable(fields):
+        fields = fields()
+
+    if not isinstance(fields, dict):
+        # Support Django models
+        fields = {getattr(f, "name", str(f)): f for f in fields if not getattr(f, "auto_created", False)}
+
+    return fields

Diff for: tests/fixtures/django.py

@@ -0,0 +1,23 @@
+from django import setup
+from django.conf import settings
+from django.db import models
+
+settings.configure()
+setup()
+
+
+class Person(models.Model):
+    """Simple Django Model for a person's information"""
+    name = models.CharField(verbose_name='Name')
+    age = models.IntegerField(verbose_name='Age')
+    parent = models.ForeignKey(verbose_name='Parent', to='Child', on_delete=models.CASCADE)
+
+    class Meta:
+        app_label = 'django'
+
+
+class Child(models.Model):
+    name: str = models.CharField(verbose_name='Name')
+
+    class Meta:
+        app_label = 'django'

Diff for: tests/test_loader.py

@@ -6,6 +6,7 @@
 from typing import Set
 
 import pytest
+from django.db.models.fields import CharField
 from marshmallow import fields
 from tests import FIXTURES_DIR
 
@@ -230,6 +231,16 @@ def test_loading_pydantic_model():
     assert "pydantic-field" in labels_attr.properties
 
 
+def test_loading_django_model():
+    """Handle Django models"""
+    loader = Loader()
+    obj = loader.get_object_documentation("tests.fixtures.django.Person")
+    assert obj.docstring == "Simple Django Model for a person's information"
+    name_attr = next(attr for attr in obj.attributes if attr.name == "name")
+    assert name_attr.type == CharField
+    assert name_attr.docstring == "Name"
+
+
 def test_loading_marshmallow_model():
     """Handle Marshmallow models."""
     loader = Loader()