django1/django/newforms/forms.py

310 lines
12 KiB
Python

"""
Form classes
"""
from django.utils.datastructures import SortedDict, MultiValueDict
from django.utils.html import escape
from fields import Field
from widgets import TextInput, Textarea, HiddenInput, MultipleHiddenInput
from util import flatatt, StrAndUnicode, ErrorDict, ErrorList, ValidationError
import copy
__all__ = ('BaseForm', 'Form')
NON_FIELD_ERRORS = '__all__'
def pretty_name(name):
"Converts 'first_name' to 'First name'"
name = name[0].upper() + name[1:]
return name.replace('_', ' ')
class SortedDictFromList(SortedDict):
"A dictionary that keeps its keys in the order in which they're inserted."
# This is different than django.utils.datastructures.SortedDict, because
# this takes a list/tuple as the argument to __init__().
def __init__(self, data=None):
if data is None: data = []
self.keyOrder = [d[0] for d in data]
dict.__init__(self, dict(data))
def copy(self):
return SortedDictFromList([(k, copy.copy(v)) for k, v in self.items()])
class DeclarativeFieldsMetaclass(type):
"""
Metaclass that converts Field attributes to a dictionary called
'base_fields', taking into account parent class 'base_fields' as well.
"""
def __new__(cls, name, bases, attrs):
fields = [(field_name, attrs.pop(field_name)) for field_name, obj in attrs.items() if isinstance(obj, Field)]
fields.sort(lambda x, y: cmp(x[1].creation_counter, y[1].creation_counter))
# If this class is subclassing another Form, add that Form's fields.
# Note that we loop over the bases in *reverse*. This is necessary in
# order to preserve the correct order of fields.
for base in bases[::-1]:
if hasattr(base, 'base_fields'):
fields = base.base_fields.items() + fields
attrs['base_fields'] = SortedDictFromList(fields)
return type.__new__(cls, name, bases, attrs)
class BaseForm(StrAndUnicode):
# This is the main implementation of all the Form logic. Note that this
# class is different than Form. See the comments by the Form class for more
# information. Any improvements to the form API should be made to *this*
# class, not to the Form class.
def __init__(self, data=None, auto_id='id_%s', prefix=None, initial=None):
self.is_bound = data is not None
self.data = data or {}
self.auto_id = auto_id
self.prefix = prefix
self.initial = initial or {}
self.__errors = None # Stores the errors after clean() has been called.
# The base_fields class attribute is the *class-wide* definition of
# fields. Because a particular *instance* of the class might want to
# alter self.fields, we create self.fields here by copying base_fields.
# Instances should always modify self.fields; they should not modify
# self.base_fields.
self.fields = self.base_fields.copy()
def __unicode__(self):
return self.as_table()
def __iter__(self):
for name, field in self.fields.items():
yield BoundField(self, field, name)
def __getitem__(self, name):
"Returns a BoundField with the given name."
try:
field = self.fields[name]
except KeyError:
raise KeyError('Key %r not found in Form' % name)
return BoundField(self, field, name)
def _errors(self):
"Returns an ErrorDict for self.data"
if self.__errors is None:
self.full_clean()
return self.__errors
errors = property(_errors)
def is_valid(self):
"""
Returns True if the form has no errors. Otherwise, False. If errors are
being ignored, returns False.
"""
return self.is_bound and not bool(self.errors)
def add_prefix(self, field_name):
"""
Returns the field name with a prefix appended, if this Form has a
prefix set.
Subclasses may wish to override.
"""
return self.prefix and ('%s-%s' % (self.prefix, field_name)) or field_name
def _html_output(self, normal_row, error_row, row_ender, help_text_html, errors_on_separate_row):
"Helper function for outputting HTML. Used by as_table(), as_ul(), as_p()."
top_errors = self.non_field_errors() # Errors that should be displayed above all fields.
output, hidden_fields = [], []
for name, field in self.fields.items():
bf = BoundField(self, field, name)
bf_errors = ErrorList([escape(error) for error in bf.errors]) # Escape and cache in local variable.
if bf.is_hidden:
if bf_errors:
top_errors.extend(['(Hidden field %s) %s' % (name, e) for e in bf_errors])
hidden_fields.append(unicode(bf))
else:
if errors_on_separate_row and bf_errors:
output.append(error_row % bf_errors)
label = bf.label and bf.label_tag(escape(bf.label + ':')) or ''
if field.help_text:
help_text = help_text_html % field.help_text
else:
help_text = u''
output.append(normal_row % {'errors': bf_errors, 'label': label, 'field': unicode(bf), 'help_text': help_text})
if top_errors:
output.insert(0, error_row % top_errors)
if hidden_fields: # Insert any hidden fields in the last row.
str_hidden = u''.join(hidden_fields)
if output:
last_row = output[-1]
# Chop off the trailing row_ender (e.g. '</td></tr>') and insert the hidden fields.
output[-1] = last_row[:-len(row_ender)] + str_hidden + row_ender
else: # If there aren't any rows in the output, just append the hidden fields.
output.append(str_hidden)
return u'\n'.join(output)
def as_table(self):
"Returns this form rendered as HTML <tr>s -- excluding the <table></table>."
return self._html_output(u'<tr><th>%(label)s</th><td>%(errors)s%(field)s%(help_text)s</td></tr>', u'<tr><td colspan="2">%s</td></tr>', '</td></tr>', u'<br />%s', False)
def as_ul(self):
"Returns this form rendered as HTML <li>s -- excluding the <ul></ul>."
return self._html_output(u'<li>%(errors)s%(label)s %(field)s%(help_text)s</li>', u'<li>%s</li>', '</li>', u' %s', False)
def as_p(self):
"Returns this form rendered as HTML <p>s."
return self._html_output(u'<p>%(label)s %(field)s%(help_text)s</p>', u'<p>%s</p>', '</p>', u' %s', True)
def non_field_errors(self):
"""
Returns an ErrorList of errors that aren't associated with a particular
field -- i.e., from Form.clean(). Returns an empty ErrorList if there
are none.
"""
return self.errors.get(NON_FIELD_ERRORS, ErrorList())
def full_clean(self):
"""
Cleans all of self.data and populates self.__errors and self.clean_data.
"""
errors = ErrorDict()
if not self.is_bound: # Stop further processing.
self.__errors = errors
return
self.clean_data = {}
for name, field in self.fields.items():
# value_from_datadict() gets the data from the dictionary.
# Each widget type knows how to retrieve its own data, because some
# widgets split data over several HTML fields.
value = field.widget.value_from_datadict(self.data, self.add_prefix(name))
try:
value = field.clean(value)
self.clean_data[name] = value
if hasattr(self, 'clean_%s' % name):
value = getattr(self, 'clean_%s' % name)()
self.clean_data[name] = value
except ValidationError, e:
errors[name] = e.messages
try:
self.clean_data = self.clean()
except ValidationError, e:
errors[NON_FIELD_ERRORS] = e.messages
if errors:
delattr(self, 'clean_data')
self.__errors = errors
def clean(self):
"""
Hook for doing any extra form-wide cleaning after Field.clean() been
called on every field. Any ValidationError raised by this method will
not be associated with a particular field; it will have a special-case
association with the field named '__all__'.
"""
return self.clean_data
class Form(BaseForm):
"A collection of Fields, plus their associated data."
# This is a separate class from BaseForm in order to abstract the way
# self.fields is specified. This class (Form) is the one that does the
# fancy metaclass stuff purely for the semantic sugar -- it allows one
# to define a form using declarative syntax.
# BaseForm itself has no way of designating self.fields.
__metaclass__ = DeclarativeFieldsMetaclass
class BoundField(StrAndUnicode):
"A Field plus data"
def __init__(self, form, field, name):
self.form = form
self.field = field
self.name = name
self.html_name = form.add_prefix(name)
if self.field.label is None:
self.label = pretty_name(name)
else:
self.label = self.field.label
self.help_text = field.help_text or ''
def __unicode__(self):
"Renders this field as an HTML widget."
# Use the 'widget' attribute on the field to determine which type
# of HTML widget to use.
value = self.as_widget(self.field.widget)
if not isinstance(value, basestring):
# Some Widget render() methods -- notably RadioSelect -- return a
# "special" object rather than a string. Call the __str__() on that
# object to get its rendered value.
value = value.__str__()
return value
def _errors(self):
"""
Returns an ErrorList for this field. Returns an empty ErrorList
if there are none.
"""
return self.form.errors.get(self.name, ErrorList())
errors = property(_errors)
def as_widget(self, widget, attrs=None):
attrs = attrs or {}
auto_id = self.auto_id
if auto_id and not attrs.has_key('id') and not widget.attrs.has_key('id'):
attrs['id'] = auto_id
if not self.form.is_bound:
data = self.form.initial.get(self.name, self.field.initial)
else:
data = self.data
return widget.render(self.html_name, data, attrs=attrs)
def as_text(self, attrs=None):
"""
Returns a string of HTML for representing this as an <input type="text">.
"""
return self.as_widget(TextInput(), attrs)
def as_textarea(self, attrs=None):
"Returns a string of HTML for representing this as a <textarea>."
return self.as_widget(Textarea(), attrs)
def as_hidden(self, attrs=None):
"""
Returns a string of HTML for representing this as an <input type="hidden">.
"""
return self.as_widget(self.field.hidden_widget(), attrs)
def _data(self):
"""
Returns the data for this BoundField, or None if it wasn't given.
"""
return self.field.widget.value_from_datadict(self.form.data, self.html_name)
data = property(_data)
def label_tag(self, contents=None, attrs=None):
"""
Wraps the given contents in a <label>, if the field has an ID attribute.
Does not HTML-escape the contents. If contents aren't given, uses the
field's HTML-escaped label.
If attrs are given, they're used as HTML attributes on the <label> tag.
"""
contents = contents or escape(self.label)
widget = self.field.widget
id_ = widget.attrs.get('id') or self.auto_id
if id_:
attrs = attrs and flatatt(attrs) or ''
contents = '<label for="%s"%s>%s</label>' % (widget.id_for_label(id_), attrs, contents)
return contents
def _is_hidden(self):
"Returns True if this BoundField's widget is hidden."
return self.field.widget.is_hidden
is_hidden = property(_is_hidden)
def _auto_id(self):
"""
Calculates and returns the ID attribute for this BoundField, if the
associated Form has specified auto_id. Returns an empty string otherwise.
"""
auto_id = self.form.auto_id
if auto_id and '%s' in str(auto_id):
return str(auto_id) % self.html_name
elif auto_id:
return self.html_name
return ''
auto_id = property(_auto_id)