django1/django/newforms/forms.py

323 lines
13 KiB
Python

"""
Form classes
"""
import copy
from django.utils.datastructures import SortedDict
from django.utils.html import escape
from django.utils.encoding import StrAndUnicode, smart_unicode, force_unicode
from fields import Field
from widgets import TextInput, Textarea
from util import flatatt, ErrorDict, ErrorList, ValidationError
__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 _get_errors(self):
"Returns an ErrorDict for self.data"
if self._errors is None:
self.full_clean()
return self._errors
errors = property(_get_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, force_unicode(e)) for e in bf_errors])
hidden_fields.append(unicode(bf))
else:
if errors_on_separate_row and bf_errors:
output.append(error_row % force_unicode(bf_errors))
if bf.label:
label = escape(force_unicode(bf.label))
# Only add a colon if the label does not end in punctuation.
if label[-1] not in ':?.!':
label += ':'
label = bf.label_tag(label) or ''
else:
label = ''
if field.help_text:
help_text = help_text_html % force_unicode(field.help_text)
else:
help_text = u''
output.append(normal_row % {'errors': force_unicode(bf_errors), 'label': force_unicode(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'%s', '</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.cleaned_data.
"""
self._errors = ErrorDict()
if not self.is_bound: # Stop further processing.
return
self.cleaned_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.cleaned_data[name] = value
if hasattr(self, 'clean_%s' % name):
value = getattr(self, 'clean_%s' % name)()
self.cleaned_data[name] = value
except ValidationError, e:
self._errors[name] = e.messages
if name in self.cleaned_data:
del self.cleaned_data[name]
try:
self.cleaned_data = self.clean()
except ValidationError, e:
self._errors[NON_FIELD_ERRORS] = e.messages
if self._errors:
delattr(self, 'cleaned_data')
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.cleaned_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 __unicode__() on that
# object to get its rendered value.
value = unicode(value)
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 'id' not in attrs and 'id' not in widget.attrs:
attrs['id'] = auto_id
if not self.form.is_bound:
data = self.form.initial.get(self.name, self.field.initial)
if callable(data):
data = data()
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 smart_unicode(auto_id):
return smart_unicode(auto_id) % self.html_name
elif auto_id:
return self.html_name
return ''
auto_id = property(_auto_id)