datatracker/ietf/utils.py
Henrik Levkowetz 5872696834 Moving ietf to trunk/ietf
[[Split portion of a mixed commit.]]
 - Legacy-Id: 96.1
2007-05-04 12:37:28 +00:00

134 lines
3.8 KiB
Python

import operator
# look at snippets 59, 148, 99 for newforms helpers
# http://www.djangosnippets.org/snippets/59/
def form_decorator(fields = {}, attrs = {}, widgets = {},
labels = {}, choices = {}):
"""
This function helps to add overrides when creating forms from models/instances.
Pass in dictionary of fields to override certain fields altogether, otherwise
add widgets or labels as desired.
For example:
class Project(models.Model):
name = models.CharField(maxlength = 100)
description = models.TextField()
owner = models.ForeignKey(User)
project_fields = dict(
owner = None
)
project_widgets = dict(
name = forms.TextInput({"size":40}),
description = forms.Textarea({"rows":5, "cols":40}))
project_labels = dict(
name = "Enter your project name here"
)
callback = form_decorator(project_fields, project_widgets, project_labels)
project_form = forms.form_for_model(Project, formfield_callback = callback)
This saves having to redefine whole fields for example just to change a widget
setting or label.
"""
def formfields_callback(f, **kw):
if f.name in fields:
# replace field altogether
field = fields[f.name]
f.initial = kw.pop("initial", None)
return field
if f.name in widgets:
kw["widget"] = widgets[f.name]
if f.name in attrs:
widget = kw.pop("widget", f.formfield().widget)
if widget :
widget.attrs.update(attrs[f.name])
kw["widget"] = widget
if f.name in labels:
kw["label"] = labels[f.name]
if f.name in choices:
choice_set = choices[f.name]
if callable(choice_set) : choice_set = choice_set()
kw["choices"] = choice_set
return f.formfield(**kw)
return formfields_callback
# Caching accessor for the reverse of a ForeignKey relatinoship
# Started by axiak on #django
class FKAsOneToOne(object):
def __init__(self, field, reverse = False, query = None):
self.field = field
self.reverse = reverse
self.query = query
def __get_attr(self, instance):
if self.reverse:
field_name = '%s_set' % self.field
else:
field_name = self.field
return getattr(instance, field_name)
def __get__(self, instance, Model):
if not hasattr(instance, '_field_values'):
instance._field_values = {}
try:
return instance._field_values[self.field]
except KeyError:
pass
if self.reverse:
value_set = self.__get_attr(instance).all()
if self.query:
value_set = value_set.filter(self.query)
try:
instance._field_values[self.field] = value_set[0]
except IndexError:
instance._field_values[self.field] = None
else:
instance._field_values[self.field] = self.__get_attr(instance)
return instance._field_values[self.field]
def __set__(self, instance, value):
if self.reverse:
# this is dangerous
#other_instance = self.__get_attr(instance).all()[0]
#setattr(other_instance, self.field, value)
#other_instance.save()
raise NotImplemented
else:
setattr(instance, self.field, value)
def orl(list):
""" Return the "or" of every element in a list.
Used to generate "or" queries with a list of Q objects. """
return reduce(operator.__or__, list)
def flattenl(list):
""" Flatten a list one level, e.g., turn
[ ['a'], ['b'], ['c', 'd'] ] into
[ 'a', 'b', 'c', 'd' ]
"""
return reduce(operator.__concat__, list)