forked from s434650/CatOrNot
419 lines
17 KiB
Python
419 lines
17 KiB
Python
"""
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Form generation utilities for App Engine's new ``ndb.Model`` class.
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The goal of ``model_form()`` is to provide a clean, explicit and predictable
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way to create forms based on ``ndb.Model`` classes. No malabarism or black
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magic should be necessary to generate a form for models, and to add custom
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non-model related fields: ``model_form()`` simply generates a form class
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that can be used as it is, or that can be extended directly or even be used
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to create other forms using ``model_form()``.
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Example usage:
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.. code-block:: python
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from google.appengine.ext import ndb
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from wtforms.ext.appengine.ndb import model_form
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# Define an example model and add a record.
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class Contact(ndb.Model):
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name = ndb.StringProperty(required=True)
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city = ndb.StringProperty()
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age = ndb.IntegerProperty(required=True)
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is_admin = ndb.BooleanProperty(default=False)
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new_entity = Contact(key_name='test', name='Test Name', age=17)
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new_entity.put()
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# Generate a form based on the model.
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ContactForm = model_form(Contact)
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# Get a form populated with entity data.
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entity = Contact.get_by_key_name('test')
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form = ContactForm(obj=entity)
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Properties from the model can be excluded from the generated form, or it can
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include just a set of properties. For example:
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.. code-block:: python
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# Generate a form based on the model, excluding 'city' and 'is_admin'.
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ContactForm = model_form(Contact, exclude=('city', 'is_admin'))
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# or...
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# Generate a form based on the model, only including 'name' and 'age'.
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ContactForm = model_form(Contact, only=('name', 'age'))
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The form can be generated setting field arguments:
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.. code-block:: python
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ContactForm = model_form(Contact, only=('name', 'age'), field_args={
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'name': {
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'label': 'Full name',
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'description': 'Your name',
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},
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'age': {
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'label': 'Age',
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'validators': [validators.NumberRange(min=14, max=99)],
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}
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})
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The class returned by ``model_form()`` can be used as a base class for forms
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mixing non-model fields and/or other model forms. For example:
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.. code-block:: python
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# Generate a form based on the model.
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BaseContactForm = model_form(Contact)
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# Generate a form based on other model.
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ExtraContactForm = model_form(MyOtherModel)
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class ContactForm(BaseContactForm):
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# Add an extra, non-model related field.
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subscribe_to_news = f.BooleanField()
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# Add the other model form as a subform.
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extra = f.FormField(ExtraContactForm)
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The class returned by ``model_form()`` can also extend an existing form
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class:
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.. code-block:: python
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class BaseContactForm(Form):
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# Add an extra, non-model related field.
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subscribe_to_news = f.BooleanField()
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# Generate a form based on the model.
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ContactForm = model_form(Contact, base_class=BaseContactForm)
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"""
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from wtforms import Form, validators, fields as f
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from wtforms.compat import string_types
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from wtforms.ext.appengine.fields import GeoPtPropertyField, KeyPropertyField, StringListPropertyField, IntegerListPropertyField
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def get_TextField(kwargs):
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"""
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Returns a ``TextField``, applying the ``ndb.StringProperty`` length limit
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of 500 bytes.
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"""
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kwargs['validators'].append(validators.length(max=500))
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return f.TextField(**kwargs)
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def get_IntegerField(kwargs):
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"""
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Returns an ``IntegerField``, applying the ``ndb.IntegerProperty`` range
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limits.
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"""
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v = validators.NumberRange(min=-0x8000000000000000, max=0x7fffffffffffffff)
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kwargs['validators'].append(v)
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return f.IntegerField(**kwargs)
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class ModelConverterBase(object):
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def __init__(self, converters=None):
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"""
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Constructs the converter, setting the converter callables.
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:param converters:
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A dictionary of converter callables for each property type. The
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callable must accept the arguments (model, prop, kwargs).
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"""
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self.converters = {}
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for name in dir(self):
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if not name.startswith('convert_'):
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continue
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self.converters[name[8:]] = getattr(self, name)
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def convert(self, model, prop, field_args):
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"""
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Returns a form field for a single model property.
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:param model:
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The ``db.Model`` class that contains the property.
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:param prop:
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The model property: a ``db.Property`` instance.
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:param field_args:
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Optional keyword arguments to construct the field.
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"""
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prop_type_name = type(prop).__name__
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# Check for generic property
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if(prop_type_name == "GenericProperty"):
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# Try to get type from field args
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generic_type = field_args.get("type")
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if generic_type:
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prop_type_name = field_args.get("type")
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# If no type is found, the generic property uses string set in convert_GenericProperty
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kwargs = {
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'label': prop._code_name.replace('_', ' ').title(),
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'default': prop._default,
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'validators': [],
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}
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if field_args:
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kwargs.update(field_args)
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if prop._required and prop_type_name not in self.NO_AUTO_REQUIRED:
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kwargs['validators'].append(validators.required())
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if kwargs.get('choices', None):
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# Use choices in a select field.
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kwargs['choices'] = [(v, v) for v in kwargs.get('choices')]
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return f.SelectField(**kwargs)
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if prop._choices:
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# Use choices in a select field.
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kwargs['choices'] = [(v, v) for v in prop._choices]
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return f.SelectField(**kwargs)
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else:
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converter = self.converters.get(prop_type_name, None)
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if converter is not None:
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return converter(model, prop, kwargs)
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else:
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return self.fallback_converter(model, prop, kwargs)
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class ModelConverter(ModelConverterBase):
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"""
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Converts properties from a ``ndb.Model`` class to form fields.
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Default conversions between properties and fields:
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+====================+===================+==============+==================+
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| Property subclass | Field subclass | datatype | notes |
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+====================+===================+==============+==================+
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| StringProperty | TextField | unicode | TextArea | repeated support
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| | | | if multiline |
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+--------------------+-------------------+--------------+------------------+
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| BooleanProperty | BooleanField | bool | |
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+--------------------+-------------------+--------------+------------------+
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| IntegerProperty | IntegerField | int or long | | repeated support
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+--------------------+-------------------+--------------+------------------+
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| FloatProperty | TextField | float | |
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+--------------------+-------------------+--------------+------------------+
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| DateTimeProperty | DateTimeField | datetime | skipped if |
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| | | | auto_now[_add] |
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+--------------------+-------------------+--------------+------------------+
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| DateProperty | DateField | date | skipped if |
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| | | | auto_now[_add] |
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+--------------------+-------------------+--------------+------------------+
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| TimeProperty | DateTimeField | time | skipped if |
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| | | | auto_now[_add] |
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+--------------------+-------------------+--------------+------------------+
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| TextProperty | TextAreaField | unicode | |
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+--------------------+-------------------+--------------+------------------+
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| GeoPtProperty | TextField | db.GeoPt | |
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+--------------------+-------------------+--------------+------------------+
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| KeyProperty | KeyProperyField | ndb.Key | |
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+--------------------+-------------------+--------------+------------------+
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| BlobKeyProperty | None | ndb.BlobKey | always skipped |
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+--------------------+-------------------+--------------+------------------+
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| UserProperty | None | users.User | always skipped |
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+--------------------+-------------------+--------------+------------------+
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| StructuredProperty | None | ndb.Model | always skipped |
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+--------------------+-------------------+--------------+------------------+
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| LocalStructuredPro | None | ndb.Model | always skipped |
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+--------------------+-------------------+--------------+------------------+
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| JsonProperty | TextField | unicode | |
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+--------------------+-------------------+--------------+------------------+
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| PickleProperty | None | bytedata | always skipped |
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+--------------------+-------------------+--------------+------------------+
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| GenericProperty | None | generic | always skipped |
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+--------------------+-------------------+--------------+------------------+
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| ComputedProperty | none | | always skipped |
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+====================+===================+==============+==================+
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"""
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# Don't automatically add a required validator for these properties
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NO_AUTO_REQUIRED = frozenset(['ListProperty', 'StringListProperty', 'BooleanProperty'])
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def convert_StringProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.StringProperty``."""
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if prop._repeated:
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return StringListPropertyField(**kwargs)
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kwargs['validators'].append(validators.length(max=500))
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return get_TextField(kwargs)
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def convert_BooleanProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.BooleanProperty``."""
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return f.BooleanField(**kwargs)
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def convert_IntegerProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.IntegerProperty``."""
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if prop._repeated:
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return IntegerListPropertyField(**kwargs)
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return get_IntegerField(kwargs)
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def convert_FloatProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.FloatProperty``."""
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return f.FloatField(**kwargs)
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def convert_DateTimeProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.DateTimeProperty``."""
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if prop._auto_now or prop._auto_now_add:
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return None
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return f.DateTimeField(format='%Y-%m-%d %H:%M:%S', **kwargs)
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def convert_DateProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.DateProperty``."""
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if prop._auto_now or prop._auto_now_add:
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return None
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return f.DateField(format='%Y-%m-%d', **kwargs)
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def convert_TimeProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.TimeProperty``."""
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if prop._auto_now or prop._auto_now_add:
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return None
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return f.DateTimeField(format='%H:%M:%S', **kwargs)
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def convert_RepeatedProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.ListProperty``."""
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return None
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def convert_UserProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.UserProperty``."""
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return None
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def convert_StructuredProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.ListProperty``."""
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return None
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def convert_LocalStructuredProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.ListProperty``."""
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return None
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def convert_JsonProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.ListProperty``."""
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return None
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def convert_PickleProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.ListProperty``."""
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return None
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def convert_GenericProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.ListProperty``."""
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kwargs['validators'].append(validators.length(max=500))
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return get_TextField(kwargs)
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def convert_BlobKeyProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.BlobKeyProperty``."""
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return f.FileField(**kwargs)
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def convert_TextProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.TextProperty``."""
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return f.TextAreaField(**kwargs)
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def convert_ComputedProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.ComputedProperty``."""
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return None
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def convert_GeoPtProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.GeoPtProperty``."""
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return GeoPtPropertyField(**kwargs)
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def convert_KeyProperty(self, model, prop, kwargs):
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"""Returns a form field for a ``ndb.KeyProperty``."""
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if 'reference_class' not in kwargs:
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try:
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reference_class = prop._kind
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except AttributeError:
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reference_class = prop._reference_class
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if isinstance(reference_class, string_types):
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# reference class is a string, try to retrieve the model object.
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mod = __import__(model.__module__, None, None, [reference_class], 0)
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reference_class = getattr(mod, reference_class)
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kwargs['reference_class'] = reference_class
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kwargs.setdefault('allow_blank', not prop._required)
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return KeyPropertyField(**kwargs)
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def model_fields(model, only=None, exclude=None, field_args=None,
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converter=None):
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"""
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Extracts and returns a dictionary of form fields for a given
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``db.Model`` class.
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:param model:
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The ``db.Model`` class to extract fields from.
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:param only:
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An optional iterable with the property names that should be included in
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the form. Only these properties will have fields.
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:param exclude:
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An optional iterable with the property names that should be excluded
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from the form. All other properties will have fields.
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:param field_args:
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An optional dictionary of field names mapping to a keyword arguments
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used to construct each field object.
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:param converter:
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A converter to generate the fields based on the model properties. If
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not set, ``ModelConverter`` is used.
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"""
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converter = converter or ModelConverter()
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field_args = field_args or {}
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# Get the field names we want to include or exclude, starting with the
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# full list of model properties.
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props = model._properties
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field_names = list(x[0] for x in sorted(props.items(), key=lambda x: x[1]._creation_counter))
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if only:
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field_names = list(f for f in only if f in field_names)
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elif exclude:
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field_names = list(f for f in field_names if f not in exclude)
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# Create all fields.
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field_dict = {}
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for name in field_names:
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field = converter.convert(model, props[name], field_args.get(name))
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if field is not None:
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field_dict[name] = field
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return field_dict
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def model_form(model, base_class=Form, only=None, exclude=None, field_args=None,
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converter=None):
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"""
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Creates and returns a dynamic ``wtforms.Form`` class for a given
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``ndb.Model`` class. The form class can be used as it is or serve as a base
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for extended form classes, which can then mix non-model related fields,
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subforms with other model forms, among other possibilities.
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:param model:
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The ``ndb.Model`` class to generate a form for.
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:param base_class:
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Base form class to extend from. Must be a ``wtforms.Form`` subclass.
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:param only:
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An optional iterable with the property names that should be included in
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the form. Only these properties will have fields.
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:param exclude:
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An optional iterable with the property names that should be excluded
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from the form. All other properties will have fields.
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:param field_args:
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An optional dictionary of field names mapping to keyword arguments
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used to construct each field object.
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:param converter:
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A converter to generate the fields based on the model properties. If
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not set, ``ModelConverter`` is used.
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"""
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# Extract the fields from the model.
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field_dict = model_fields(model, only, exclude, field_args, converter)
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# Return a dynamically created form class, extending from base_class and
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# including the created fields as properties.
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return type(model._get_kind() + 'Form', (base_class,), field_dict)
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