+
−#!/usr/bin/python2.5
+
−#
+
−# Copyright 2008 the Melange authors.
+
−#
+
−# Licensed under the Apache License, Version 2.0 (the "License");
+
−# you may not use this file except in compliance with the License.
+
−# You may obtain a copy of the License at
+
−#
+
−#   http://www.apache.org/licenses/LICENSE-2.0
+
−#
+
−# Unless required by applicable law or agreed to in writing, software
+
−# distributed under the License is distributed on an "AS IS" BASIS,
+
−# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
−# See the License for the specific language governing permissions and
+
−# limitations under the License.
+
−
+
−"""This module defines classes and functions for Dynamic Forms.
+
−"""
+
−
+
−__authors__ = [
+
−    '"Sverre Rabbelier" <sverre@rabbelier.nl>',
+
−    ]
+
−
+
−
+
−from google.appengine.ext.db import djangoforms
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−
+
−from soc.logic import dicts
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−
+
−
+
−class DynaFormMetaclass(djangoforms.ModelFormMetaclass):
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−  """The DynaForm Meta class, adding support for dynamically defined fields.
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−
+
−  The new DynaForm class that is created by class function is very
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−  similar to one created by the regular djangoforms.ModelFormMetaclass.
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−  The only difference is that is the form class has a Meta property,
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−  it's 'dynaconf' field will be used to define additional properties
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−  in the form class.
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−
+
−  The 'dynaconf' field (if present), is expected to be iterable as a
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−  dictionary (with iteritems). The keys are used as the property names,
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−  and the values are used as the property value.
+
−  """
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−
+
−  def __new__(mcs, class_name, bases, attrs):
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−    """See djangoforms.ModelFormMetaclass on how the __new__ method
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−    is used, for an explanation on how this class modifies the default
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−    behavior, see the DynaFormMetaclass's docstring.
+
−    """
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−
+
−    # Retrieve the Meta class, if present
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−    meta = attrs.get('Meta', None)
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−    conf = None
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−
+
−    # Try to retrieve the dynaconf property
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−    if meta:
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−      conf = getattr(meta, 'dynaconf', None)
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−
+
−    # When found, extend the form's attribute's with the specified ones
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−    if conf:
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−      for key, value in conf.iteritems():
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−        attrs[key] = value
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−
+
−    # Leave the rest to djangoforms.ModelFormMetaclass.
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−    return super(DynaFormMetaclass, mcs).__new__(mcs, class_name, bases, attrs)
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−
+
−
+
−def newDynaForm(dynamodel=None, dynabase=None, dynainclude=None, 
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−                dynaexclude=None, dynaproperties=None):
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−  """Creates a new form DynaForm class.
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−
+
−  The returned class extends dynabase, but with the following additions:
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−  * It has a Meta class with the 'model', 'include', and 'exclude'
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−  fields set as specified by newDynaForm's keyword arguments.
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−  * It's __metaclass__ is set to DynaFormMetaclass (which inherits from
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−  the default djangoforms.ModelFormMetaclass).
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−  * The Meta class has an additional dynaconf field which is set to
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−  the dyanfields keyword argument passed to newDynaForm.
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−
+
−  See DynaFormMetaclass for an explanation on how the dynaproperties
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−  property is used to construct the DynaForm class.
+
−  """
+
−
+
−  class DynaForm(dynabase):
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−    """The dynamically created Form class
+
−    """
+
−
+
−    __metaclass__ = DynaFormMetaclass
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−
+
−    class Meta:
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−      """Inner Meta class that defines some behavior for the form.
+
−      """
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−
+
−      model = dynamodel
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−      include = dynainclude
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−      exclude = dynaexclude
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−      dynaconf = dynaproperties
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−
+
−  return DynaForm
+
−
+
−
+
−def extendDynaForm(dynaform, dynainclude=None, dynaexclude=None, 
+
−                   dynaproperties=None, append=False):
+
−  """Extends an existing dynaform.
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−
+
−  If any of dynainclude, dynaexclude or dynaproperties are not present,
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−  they are retrieved from dynaform (if present in it's Meta class).
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−
+
−  While it is rather useless to extend from a dynaform that does not have
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−  a Meta class, it is allowed, the resulting DynaForm is the same as if
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−  newDynaForm was called with all extendDynForm's keyword arguments.
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−
+
−  If append is True, the form's original values for include and
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−  exclude will be appended to the supplied dynainclude and
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−  dynaexclude, which both are still allowed to be None.
+
−  """
+
−
+
−  # Try to retrieve the Meta class from the existing dynaform
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−  meta = getattr(dynaform, 'Meta', None)
+
−
+
−  # If we find one, we can use it to 'extend' from
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−  if meta:
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−    dynamodel = getattr(meta, 'model', None)
+
−
+
−    originclude = getattr(meta, 'include', [])
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−    origexclude = getattr(meta, 'exclude', [])
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−
+
−    if not dynainclude:
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−      dynainclude = originclude
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−      originclude = []
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−    if not dynaexclude:
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−      dynaexclude = origexclude
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−      origexclude = []
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−
+
−    if append:
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−      dynainclude += originclude
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−      dynaexclude += origexclude
+
−
+
−    # The most interesting parameter, the 'extra fields' dictionary
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−    dynaconf = getattr(meta, 'dynaconf', {})
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−    if not dynaproperties:
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−      dynaproperties = dynaconf
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−    else:
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−      dicts.merge(dynaproperties, dynaconf)
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−
+
−  # Create a new DynaForm, using the properties we extracted
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−  return newDynaForm(
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−      dynamodel=dynamodel,
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−      dynabase=dynaform,
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−      dynainclude=dynainclude,
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−      dynaexclude=dynaexclude,
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−      dynaproperties=dynaproperties)
+
−
+
−
+
−class DynaFieldMetaclass(type):
+
−  """The DynaField Meta class, adding support for dynamic properties.
+
−
+
−  The new DynaField class that is created by class function is only
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−  modified slightly. The only difference is that if the field class has
+
−  a dynaproperties property, it will be used to define additional properties
+
−  for the field.
+
−
+
−  The 'dynaproperties' property (if present), is expected to be iterable as a
+
−  dictionary (with iteritems). The keys are used as the property names,
+
−  and the values are used as the property value.
+
−  """
+
−
+
−  def __new__(mcs, name, bases, attrs):
+
−    """See djangoforms.ModelFormMetaclass on how the __new__ method
+
−    is used, for an explanation on how this class modifies the default
+
−    behavior, see the DynaFormMetaclass's docstring.
+
−    """
+
−
+
−    # Retrieve the Meta class, if present
+
−    dynaproperties = attrs.get('dynaproperties', {})
+
−
+
−    for key, value in dynaproperties.iteritems():
+
−      attrs[key] = value
+
−
+
−    # Leave the rest to type
+
−    return super(DynaFieldMetaclass, mcs).__new__(mcs, name, bases, attrs)
+
−
+
−
+
−def newDynaField(field, base, passthrough):
+
−  """Creates a new form DynaField class.
+
−
+
−  The returned class extends base, but with the following additions:
+
−  * It has a dynaproperties attribute as extracted from field.
+
−  * It's __metaclass__ is set to DynaFieldMetaclass (which inherits from
+
−  the default type class).
+
−
+
−  See DynaFieldMetaclass for an explanation on how the dynaproperties
+
−  property is used to construct the DynaForm class.
+
−  """
+
−
+
−  # pass only known accepted arguments to super
+
−  init_args = dicts.filter(field, passthrough)
+
−
+
−  properties = field.copy()
+
−
+
−  # all pass through arguments are handled by super
+
−  for key in passthrough:
+
−    if key in properties:
+
−      del properties[key]
+
−
+
−  # pylint: disable-msg=E1002
+
−  class DynaField(base):
+
−    """The dynamically created Field class.
+
−    """
+
−
+
−    __metaclass__ = DynaFieldMetaclass
+
−    dynaproperties = properties
+
−
+
−    def __init__(self):
+
−      """Pass through the init args to super.
+
−      """
+
−
+
−      super(DynaField, self).__init__(**init_args)
+
−
+
−  return DynaField