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- """
- Form generation utilities for App Engine's new ``ndb.Model`` class.
- The goal of ``model_form()`` is to provide a clean, explicit and predictable
- way to create forms based on ``ndb.Model`` classes. No malabarism or black
- magic should be necessary to generate a form for models, and to add custom
- non-model related fields: ``model_form()`` simply generates a form class
- that can be used as it is, or that can be extended directly or even be used
- to create other forms using ``model_form()``.
- Example usage:
- .. code-block:: python
- from google.appengine.ext import ndb
- from wtforms.ext.appengine.ndb import model_form
- # Define an example model and add a record.
- class Contact(ndb.Model):
- name = ndb.StringProperty(required=True)
- city = ndb.StringProperty()
- age = ndb.IntegerProperty(required=True)
- is_admin = ndb.BooleanProperty(default=False)
- new_entity = Contact(key_name='test', name='Test Name', age=17)
- new_entity.put()
- # Generate a form based on the model.
- ContactForm = model_form(Contact)
- # Get a form populated with entity data.
- entity = Contact.get_by_key_name('test')
- form = ContactForm(obj=entity)
- Properties from the model can be excluded from the generated form, or it can
- include just a set of properties. For example:
- .. code-block:: python
- # Generate a form based on the model, excluding 'city' and 'is_admin'.
- ContactForm = model_form(Contact, exclude=('city', 'is_admin'))
- # or...
- # Generate a form based on the model, only including 'name' and 'age'.
- ContactForm = model_form(Contact, only=('name', 'age'))
- The form can be generated setting field arguments:
- .. code-block:: python
- ContactForm = model_form(Contact, only=('name', 'age'), field_args={
- 'name': {
- 'label': 'Full name',
- 'description': 'Your name',
- },
- 'age': {
- 'label': 'Age',
- 'validators': [validators.NumberRange(min=14, max=99)],
- }
- })
- The class returned by ``model_form()`` can be used as a base class for forms
- mixing non-model fields and/or other model forms. For example:
- .. code-block:: python
- # Generate a form based on the model.
- BaseContactForm = model_form(Contact)
- # Generate a form based on other model.
- ExtraContactForm = model_form(MyOtherModel)
- class ContactForm(BaseContactForm):
- # Add an extra, non-model related field.
- subscribe_to_news = f.BooleanField()
- # Add the other model form as a subform.
- extra = f.FormField(ExtraContactForm)
- The class returned by ``model_form()`` can also extend an existing form
- class:
- .. code-block:: python
- class BaseContactForm(Form):
- # Add an extra, non-model related field.
- subscribe_to_news = f.BooleanField()
- # Generate a form based on the model.
- ContactForm = model_form(Contact, base_class=BaseContactForm)
- """
- from wtforms import Form, validators, fields as f
- from wtforms.compat import string_types
- from wtforms.ext.appengine.fields import GeoPtPropertyField, KeyPropertyField, StringListPropertyField, IntegerListPropertyField
- def get_TextField(kwargs):
- """
- Returns a ``TextField``, applying the ``ndb.StringProperty`` length limit
- of 500 bytes.
- """
- kwargs['validators'].append(validators.length(max=500))
- return f.TextField(**kwargs)
- def get_IntegerField(kwargs):
- """
- Returns an ``IntegerField``, applying the ``ndb.IntegerProperty`` range
- limits.
- """
- v = validators.NumberRange(min=-0x8000000000000000, max=0x7fffffffffffffff)
- kwargs['validators'].append(v)
- return f.IntegerField(**kwargs)
- class ModelConverterBase(object):
- def __init__(self, converters=None):
- """
- Constructs the converter, setting the converter callables.
- :param converters:
- A dictionary of converter callables for each property type. The
- callable must accept the arguments (model, prop, kwargs).
- """
- self.converters = {}
- for name in dir(self):
- if not name.startswith('convert_'):
- continue
- self.converters[name[8:]] = getattr(self, name)
- def convert(self, model, prop, field_args):
- """
- Returns a form field for a single model property.
- :param model:
- The ``db.Model`` class that contains the property.
- :param prop:
- The model property: a ``db.Property`` instance.
- :param field_args:
- Optional keyword arguments to construct the field.
- """
- prop_type_name = type(prop).__name__
- # Check for generic property
- if(prop_type_name == "GenericProperty"):
- # Try to get type from field args
- generic_type = field_args.get("type")
- if generic_type:
- prop_type_name = field_args.get("type")
- # If no type is found, the generic property uses string set in convert_GenericProperty
- kwargs = {
- 'label': prop._code_name.replace('_', ' ').title(),
- 'default': prop._default,
- 'validators': [],
- }
- if field_args:
- kwargs.update(field_args)
- if prop._required and prop_type_name not in self.NO_AUTO_REQUIRED:
- kwargs['validators'].append(validators.required())
- if kwargs.get('choices', None):
- # Use choices in a select field.
- kwargs['choices'] = [(v, v) for v in kwargs.get('choices')]
- return f.SelectField(**kwargs)
- if prop._choices:
- # Use choices in a select field.
- kwargs['choices'] = [(v, v) for v in prop._choices]
- return f.SelectField(**kwargs)
- else:
- converter = self.converters.get(prop_type_name, None)
- if converter is not None:
- return converter(model, prop, kwargs)
- else:
- return self.fallback_converter(model, prop, kwargs)
- class ModelConverter(ModelConverterBase):
- """
- Converts properties from a ``ndb.Model`` class to form fields.
- Default conversions between properties and fields:
- +====================+===================+==============+==================+
- | Property subclass | Field subclass | datatype | notes |
- +====================+===================+==============+==================+
- | StringProperty | TextField | unicode | TextArea | repeated support
- | | | | if multiline |
- +--------------------+-------------------+--------------+------------------+
- | BooleanProperty | BooleanField | bool | |
- +--------------------+-------------------+--------------+------------------+
- | IntegerProperty | IntegerField | int or long | | repeated support
- +--------------------+-------------------+--------------+------------------+
- | FloatProperty | TextField | float | |
- +--------------------+-------------------+--------------+------------------+
- | DateTimeProperty | DateTimeField | datetime | skipped if |
- | | | | auto_now[_add] |
- +--------------------+-------------------+--------------+------------------+
- | DateProperty | DateField | date | skipped if |
- | | | | auto_now[_add] |
- +--------------------+-------------------+--------------+------------------+
- | TimeProperty | DateTimeField | time | skipped if |
- | | | | auto_now[_add] |
- +--------------------+-------------------+--------------+------------------+
- | TextProperty | TextAreaField | unicode | |
- +--------------------+-------------------+--------------+------------------+
- | GeoPtProperty | TextField | db.GeoPt | |
- +--------------------+-------------------+--------------+------------------+
- | KeyProperty | KeyProperyField | ndb.Key | |
- +--------------------+-------------------+--------------+------------------+
- | BlobKeyProperty | None | ndb.BlobKey | always skipped |
- +--------------------+-------------------+--------------+------------------+
- | UserProperty | None | users.User | always skipped |
- +--------------------+-------------------+--------------+------------------+
- | StructuredProperty | None | ndb.Model | always skipped |
- +--------------------+-------------------+--------------+------------------+
- | LocalStructuredPro | None | ndb.Model | always skipped |
- +--------------------+-------------------+--------------+------------------+
- | JsonProperty | TextField | unicode | |
- +--------------------+-------------------+--------------+------------------+
- | PickleProperty | None | bytedata | always skipped |
- +--------------------+-------------------+--------------+------------------+
- | GenericProperty | None | generic | always skipped |
- +--------------------+-------------------+--------------+------------------+
- | ComputedProperty | none | | always skipped |
- +====================+===================+==============+==================+
- """
- # Don't automatically add a required validator for these properties
- NO_AUTO_REQUIRED = frozenset(['ListProperty', 'StringListProperty', 'BooleanProperty'])
- def convert_StringProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.StringProperty``."""
- if prop._repeated:
- return StringListPropertyField(**kwargs)
- kwargs['validators'].append(validators.length(max=500))
- return get_TextField(kwargs)
- def convert_BooleanProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.BooleanProperty``."""
- return f.BooleanField(**kwargs)
- def convert_IntegerProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.IntegerProperty``."""
- if prop._repeated:
- return IntegerListPropertyField(**kwargs)
- return get_IntegerField(kwargs)
- def convert_FloatProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.FloatProperty``."""
- return f.FloatField(**kwargs)
- def convert_DateTimeProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.DateTimeProperty``."""
- if prop._auto_now or prop._auto_now_add:
- return None
- return f.DateTimeField(format='%Y-%m-%d %H:%M:%S', **kwargs)
- def convert_DateProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.DateProperty``."""
- if prop._auto_now or prop._auto_now_add:
- return None
- return f.DateField(format='%Y-%m-%d', **kwargs)
- def convert_TimeProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.TimeProperty``."""
- if prop._auto_now or prop._auto_now_add:
- return None
- return f.DateTimeField(format='%H:%M:%S', **kwargs)
- def convert_RepeatedProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.ListProperty``."""
- return None
- def convert_UserProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.UserProperty``."""
- return None
- def convert_StructuredProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.ListProperty``."""
- return None
- def convert_LocalStructuredProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.ListProperty``."""
- return None
- def convert_JsonProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.ListProperty``."""
- return None
- def convert_PickleProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.ListProperty``."""
- return None
- def convert_GenericProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.ListProperty``."""
- kwargs['validators'].append(validators.length(max=500))
- return get_TextField(kwargs)
- def convert_BlobKeyProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.BlobKeyProperty``."""
- return f.FileField(**kwargs)
- def convert_TextProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.TextProperty``."""
- return f.TextAreaField(**kwargs)
- def convert_ComputedProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.ComputedProperty``."""
- return None
- def convert_GeoPtProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.GeoPtProperty``."""
- return GeoPtPropertyField(**kwargs)
- def convert_KeyProperty(self, model, prop, kwargs):
- """Returns a form field for a ``ndb.KeyProperty``."""
- if 'reference_class' not in kwargs:
- try:
- reference_class = prop._kind
- except AttributeError:
- reference_class = prop._reference_class
- if isinstance(reference_class, string_types):
- # reference class is a string, try to retrieve the model object.
- mod = __import__(model.__module__, None, None, [reference_class], 0)
- reference_class = getattr(mod, reference_class)
- kwargs['reference_class'] = reference_class
- kwargs.setdefault('allow_blank', not prop._required)
- return KeyPropertyField(**kwargs)
- def model_fields(model, only=None, exclude=None, field_args=None,
- converter=None):
- """
- Extracts and returns a dictionary of form fields for a given
- ``db.Model`` class.
- :param model:
- The ``db.Model`` class to extract fields from.
- :param only:
- An optional iterable with the property names that should be included in
- the form. Only these properties will have fields.
- :param exclude:
- An optional iterable with the property names that should be excluded
- from the form. All other properties will have fields.
- :param field_args:
- An optional dictionary of field names mapping to a keyword arguments
- used to construct each field object.
- :param converter:
- A converter to generate the fields based on the model properties. If
- not set, ``ModelConverter`` is used.
- """
- converter = converter or ModelConverter()
- field_args = field_args or {}
- # Get the field names we want to include or exclude, starting with the
- # full list of model properties.
- props = model._properties
- field_names = list(x[0] for x in sorted(props.items(), key=lambda x: x[1]._creation_counter))
- if only:
- field_names = list(f for f in only if f in field_names)
- elif exclude:
- field_names = list(f for f in field_names if f not in exclude)
- # Create all fields.
- field_dict = {}
- for name in field_names:
- field = converter.convert(model, props[name], field_args.get(name))
- if field is not None:
- field_dict[name] = field
- return field_dict
- def model_form(model, base_class=Form, only=None, exclude=None, field_args=None,
- converter=None):
- """
- Creates and returns a dynamic ``wtforms.Form`` class for a given
- ``ndb.Model`` class. The form class can be used as it is or serve as a base
- for extended form classes, which can then mix non-model related fields,
- subforms with other model forms, among other possibilities.
- :param model:
- The ``ndb.Model`` class to generate a form for.
- :param base_class:
- Base form class to extend from. Must be a ``wtforms.Form`` subclass.
- :param only:
- An optional iterable with the property names that should be included in
- the form. Only these properties will have fields.
- :param exclude:
- An optional iterable with the property names that should be excluded
- from the form. All other properties will have fields.
- :param field_args:
- An optional dictionary of field names mapping to keyword arguments
- used to construct each field object.
- :param converter:
- A converter to generate the fields based on the model properties. If
- not set, ``ModelConverter`` is used.
- """
- # Extract the fields from the model.
- field_dict = model_fields(model, only, exclude, field_args, converter)
- # Return a dynamically created form class, extending from base_class and
- # including the created fields as properties.
- return type(model._get_kind() + 'Form', (base_class,), field_dict)
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