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