FormField population strategy

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 1.0.0-rc.12 : 22.09.2024
+
+- **Added**: `FormField` population strategy
+
 ## 1.0.0-rc.11 : 16.08.2024
 
 - **Fixed**: Proper manipulation with `BaseStrategy` instances during population

README.md

@@ -75,7 +75,7 @@ DJANGO_API_FORMS_POPULATION_STRATEGIES = {
     'django_api_forms.fields.FormFieldList': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django_api_forms.fields.FileField': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django_api_forms.fields.ImageField': 'django_api_forms.population_strategies.IgnoreStrategy',
-    'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.IgnoreStrategy',
+    'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.FormFieldStrategy',
     'django.forms.models.ModelMultipleChoiceField': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django.forms.models.ModelChoiceField': 'django_api_forms.population_strategies.ModelChoiceFieldStrategy'
 }
@@ -134,7 +134,7 @@ DJANGO_API_FORMS_PARSERS = {
 }
 ```
 
-**Django API Forms equivalent + validation**
+**Django API Forms equivalent + validation + population**
 
 ```python
 from enum import Enum
@@ -143,6 +143,7 @@ from django.core.exceptions import ValidationError
 from django.forms import fields
 
 from django_api_forms import FieldList, FormField, FormFieldList, DictionaryField, EnumField, AnyField, Form
+from tests.testapp.models import Artist, Album
 
 
 class AlbumType(Enum):
@@ -170,7 +171,7 @@ class SongForm(Form):
 class AlbumForm(Form):
     title = fields.CharField(max_length=100)
     year = fields.IntegerField()
-    artist = FormField(form=ArtistForm)
+    artist = FormField(form=ArtistForm, model=Artist)
     songs = FormFieldList(form=SongForm)
     type = EnumField(enum=AlbumType, required=True)
     metadata = DictionaryField(value_field=fields.DateTimeField())
@@ -180,7 +181,7 @@ class AlbumForm(Form):
             raise ValidationError("Year 1992 is forbidden!", 'forbidden-value')
         if 'param' not in self.extras:
             self.add_error(
-                ('param', ),
+                ('param',),
                 ValidationError("You can use extra optional arguments in form validation!", code='param-where')
             )
         return self.cleaned_data['year']
@@ -195,7 +196,6 @@ class AlbumForm(Form):
         return self.cleaned_data
 
 
-
 """
 Django view example
 """
@@ -208,6 +208,14 @@ def create_album(request):
     # Cleaned valid payload
     payload = form.cleaned_data
     print(payload)
+
+    # Populate cleaned data into Django model
+    album = Album()
+    form.populate(album)
+
+    # Save populated objects
+    album.artist.save()
+    album.save()
 ```
 
 If you want example with whole Django project, check out repository created by [pawl](https://github.com/pawl)

django_api_forms/fields.py

@@ -1,10 +1,10 @@
+import re
 import typing
 import warnings
 from base64 import b64decode
 from enum import Enum
 from io import BytesIO
 from mimetypes import guess_type
-import re
 
 from django.core.exceptions import ValidationError
 from django.core.files import File
@@ -86,15 +86,19 @@ def to_python(self, value) -> typing.List:
 
 
 class FormField(Field):
-    def __init__(self, form: typing.Type, **kwargs):
+    def __init__(self, form: typing.Type, model=None, **kwargs):
         self._form = form
-
+        self._model = model
         super().__init__(**kwargs)
 
     @property
     def form(self):
         return self._form
 
+    @property
+    def model(self):
+        return self._model
+
     def to_python(self, value) -> typing.Union[typing.Dict, None]:
         if not value:
             return {}
@@ -142,7 +146,7 @@ def to_python(self, value):
                 result.append(form.cleaned_data)
             else:
                 for error in form.errors:
-                    error.prepend((position, ))
+                    error.prepend((position,))
                     errors.append(error)
 
         if errors:
@@ -208,7 +212,7 @@ def to_python(self, value) -> dict:
                     key = self._key_field.clean(key)
                 result[key] = self._value_field.clean(item)
             except ValidationError as e:
-                errors[key] = DetailValidationError(e, (key, ))
+                errors[key] = DetailValidationError(e, (key,))
 
         if errors:
             raise ValidationError(errors)

django_api_forms/population_strategies.py

@@ -1,3 +1,6 @@
+import copy
+
+
 class BaseStrategy:
     def __call__(self, field, obj, key: str, value):
         setattr(obj, key, value)
@@ -34,3 +37,22 @@ def __call__(self, field, obj, key: str, value):
         if key.endswith(postfix_to_remove):
             model_key = key[:-len(postfix_to_remove)]
         setattr(obj, model_key, value)
+
+
+class FormFieldStrategy(BaseStrategy):
+    def __call__(self, field, obj, key: str, value):
+        model = field.model
+        if model:
+            from django_api_forms.settings import Settings
+
+            model = model()
+            form = field.form
+
+            form.cleaned_data = value
+            form.fields = copy.deepcopy(getattr(form, 'base_fields'))
+            form.settings = Settings()
+            form.errors = None
+
+            populated_model = form.populate(form, model)
+
+            setattr(obj, key, populated_model)

django_api_forms/settings.py

@@ -5,7 +5,7 @@
         'django_api_forms.fields.FormFieldList': 'django_api_forms.population_strategies.IgnoreStrategy',
         'django_api_forms.fields.FileField': 'django_api_forms.population_strategies.IgnoreStrategy',
         'django_api_forms.fields.ImageField': 'django_api_forms.population_strategies.IgnoreStrategy',
-        'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.IgnoreStrategy',
+        'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.FormFieldStrategy',
         'django.forms.models.ModelMultipleChoiceField': 'django_api_forms.population_strategies.IgnoreStrategy',
         'django.forms.models.ModelChoiceField': 'django_api_forms.population_strategies.ModelChoiceFieldStrategy'
     },

django_api_forms/version.py

@@ -1 +1 @@
-__version__ = '1.0.0-rc.10'
+__version__ = '1.0.0-rc.12'

docs/example.md

@@ -7,7 +7,7 @@ DJANGO_API_FORMS_POPULATION_STRATEGIES = {
     'django_api_forms.fields.FormFieldList': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django_api_forms.fields.FileField': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django_api_forms.fields.ImageField': 'django_api_forms.population_strategies.IgnoreStrategy',
-    'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.IgnoreStrategy',
+    'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.FormFieldStrategy',
     'django.forms.models.ModelMultipleChoiceField': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django.forms.models.ModelChoiceField': 'django_api_forms.population_strategies.ModelChoiceFieldStrategy'
 }
@@ -78,6 +78,7 @@ from django.core.exceptions import ValidationError
 from django.forms import fields
 
 from django_api_forms import FieldList, FormField, FormFieldList, DictionaryField, EnumField, AnyField, Form
+from tests.testapp.models import Artist, Album
 
 
 class AlbumType(Enum):
@@ -105,7 +106,7 @@ class SongForm(Form):
 class AlbumForm(Form):
     title = fields.CharField(max_length=100)
     year = fields.IntegerField()
-    artist = FormField(form=ArtistForm)
+    artist = FormField(form=ArtistForm, model=Artist)
     songs = FormFieldList(form=SongForm)
     type = EnumField(enum=AlbumType, required=True)
     metadata = DictionaryField(value_field=fields.DateTimeField())
@@ -141,4 +142,12 @@ def create_album(request):
     # Cleaned valid payload
     payload = form.cleaned_data
     print(payload)
+
+    # Populate cleaned data into Django model
+    album = Album()
+    form.populate(album)
+
+    # Save populated objects
+    album.artist.save()
+    album.save()
 ```

docs/fields.md

@@ -101,6 +101,8 @@ Field used for embedded objects represented as another API form.
 - Normalizes to: A Python dictionary
 - Required arguments:
   - `form`: Type of a nested form
+- Optional arguments:
+  - `model`: Datastructure(Django model) instance for population
 
 **JSON example**
 
@@ -124,6 +126,7 @@ Field used for embedded objects represented as another API form.
 ```python
 from django_api_forms import Form, FormField, FieldList
 from django.forms import fields
+from tests.testapp.models import Artist
 
 
 class ArtistForm(Form):
@@ -135,7 +138,7 @@ class ArtistForm(Form):
 class AlbumForm(Form):
     title = fields.CharField(max_length=100)
     year = fields.IntegerField()
-    artist = FormField(form=ArtistForm)
+    artist = FormField(form=ArtistForm, model=Artist)
 ```
 
 ## FormFieldList

docs/tutorial.md

@@ -8,11 +8,11 @@ images/files, nesting).
 
 - payload parsing (according to the `Content-Type` HTTP header)
 - data validation and normalisation (using [Django validators](https://docs.djangoproject.com/en/4.1/ref/validators/)
-or custom `clean_` method)
+  or custom `clean_` method)
 - BASE64 file/image upload
 - construction of the basic validation response
 - filling objects attributes (if possible, see exceptions) using `setattr` function (super handy for Django database
-models)
+  models)
 
 ## Construction
 
@@ -24,6 +24,7 @@ any extra argument into `Form.create_from_request(request, param1=request.GET.ge
 ```python
 from tests.testapp.forms import AlbumForm
 
+
 def my_view(request):
     form = AlbumForm.create_from_request(request=request, param=request.GET.get('param'))
 ```
@@ -80,13 +81,13 @@ class BandForm(Form):
 This process is much more simple than in classic Django form. It consists of:
 
 1. Iterating over form attributes:
-   - calling `Field.clean(value)` method
-   - calling `Form.clean_<field_name>` method
-   - calling `Form.add_error((field_name, ), error)` in case of failures in clean methods
-   - if field is marked as dirty, normalized attribute is saved to `Form.clean_data` property
+    - calling `Field.clean(value)` method
+    - calling `Form.clean_<field_name>` method
+    - calling `Form.add_error((field_name, ), error)` in case of failures in clean methods
+    - if field is marked as dirty, normalized attribute is saved to `Form.clean_data` property
 2. Calling `Form.clean` method which returns final normalized values which will be presented in `Form.clean_data`
-(feel free to override it, by default does nothing, useful for conditional validation, you can still add errors
-using `Form.add_error()`). `Form.clean` is only called when there are no errors from previous section.
+   (feel free to override it, by default does nothing, useful for conditional validation, you can still add errors
+   using `Form.add_error()`). `Form.clean` is only called when there are no errors from previous section.
 
 Normalized data are available in `Form.clean_data` property (keys suppose to correspond with values from `Form.dirty`).
 Extra optional arguments are available in `Form.extras` property (keys suppose to correspond with values
@@ -106,13 +107,14 @@ from django.forms import fields
 from django.core.exceptions import ValidationError
 from django_api_forms import Form
 
+
 class BookForm(Form):
     title = fields.CharField(max_length=100)
     year = fields.IntegerField()
 
     def clean_title(self):
         if self.cleaned_data['title'] == "The Hitchhiker's Guide to the Galaxy":
-            self.add_error(('title', ), ValidationError("Too cool!", code='too-cool'))
+            self.add_error(('title',), ValidationError("Too cool!", code='too-cool'))
 
         if 'param' not in self.extras:
             raise ValidationError("You can use extra optional arguments in form validation!")
@@ -125,7 +127,7 @@ class BookForm(Form):
 
         if 'param' not in self.extras:
             self.add_error(
-                ('param', ),
+                ('param',),
                 ValidationError("You can use extra optional arguments in form validation!", code='param-where')
             )
         # The last chance to do some touchy touchy with the self.clean_data
@@ -150,6 +152,7 @@ can use it like this:
 from tests.testapp.forms import AlbumForm
 from tests.testapp.models import Album
 
+
 def my_view(request):
     form = AlbumForm.create_from_request(request)
 
@@ -173,7 +176,7 @@ DJANGO_API_FORMS_POPULATION_STRATEGIES = {
     'django_api_forms.fields.FormFieldList': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django_api_forms.fields.FileField': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django_api_forms.fields.ImageField': 'django_api_forms.population_strategies.IgnoreStrategy',
-    'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.IgnoreStrategy',
+    'django_api_forms.fields.FormField': 'django_api_forms.population_strategies.FormFieldStrategy',
     'django.forms.models.ModelMultipleChoiceField': 'django_api_forms.population_strategies.IgnoreStrategy',
     'django.forms.models.ModelChoiceField': 'django_api_forms.population_strategies.ModelChoiceFieldStrategy'
 }
@@ -205,18 +208,44 @@ from django_api_forms import Form
 
 from tests.testapp.models import Artist
 
+
 class MyFormNoPostfix(Form):
     artist = ModelChoiceField(queryset=Artist.objects.all())
 
+
 class MyFormFieldName(Form):
     artist_name = ModelChoiceField(
         queryset=Artist.objects.all(), to_field_name='name'
     )
 
+
 class MyFormWithId(Form):
     artist_id = ModelChoiceField(queryset=Artist.objects.all())
 ```
 
+#### FormFieldStrategy
+
+If the `model` argument is omitted, the `FormFieldStrategy` will behave same as the `IgnoreStrategy`
+If a `model` argument is provided when declaring a `FormField`, the data from the nested JSON object is used to
+populate an instance of the specified Django model.
+
+```python
+from django.forms import fields
+
+from django_api_forms import FieldList, FormField, Form
+from tests.testapp.models import Artist
+
+
+class ArtistForm(Form):
+    name = fields.CharField(required=True, max_length=100)
+    genres = FieldList(field=fields.CharField(max_length=30))
+    members = fields.IntegerField()
+
+
+class AlbumForm(Form):
+    artist = FormField(form=ArtistForm, model=Artist)
+```
+
 ### Customization
 
 #### Creating custom strategy
@@ -236,8 +265,9 @@ class ExampleStrategy(BaseStrategy):
 
 #### Override strategy
 
-You can override settings population strategies by creating your own population strategy in specific local `From` class using
-`Meta` class with optional attributes `field_type_strategy = {}` or `field_strategy = {}`:
+You can override settings population strategies by creating your own population strategy in specific local `From` class
+using `Meta` class with optional attributes `field_type_strategy = {}` or `field_strategy = {}`:
+
 - `field_type_strategy`: Dictionary for overriding populate strategy on `Form` type attributes
 - `field_strategy`: Dictionary for overriding populate strategies on `Form` attributes
 
@@ -276,6 +306,7 @@ from django_api_forms import Form, FormField, EnumField, DictionaryField
 from tests.testapp.models import Album, Artist
 from tests.testapp.forms import ArtistForm
 
+
 class AlbumForm(Form):
     title = fields.CharField(max_length=100)
     year = fields.IntegerField()

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "django-api-forms"
-version = "1.0.0-rc.11"
+version = "1.0.0-rc.12"
 description = "Declarative Django request validation for RESTful APIs"
 authors = [
     "Jakub Dubec <[email protected]>",