Code source de django.forms.boundfield
from __future__ import unicode_literals
import datetime
import warnings
from django.forms.utils import flatatt, pretty_name
from django.forms.widgets import Textarea, TextInput
from django.utils import six
from django.utils.deprecation import RemovedInDjango21Warning
from django.utils.encoding import force_text, python_2_unicode_compatible
from django.utils.functional import cached_property
from django.utils.html import conditional_escape, format_html, html_safe
from django.utils.inspect import func_accepts_kwargs, func_supports_parameter
from django.utils.safestring import mark_safe
from django.utils.translation import ugettext_lazy as _
__all__ = ('BoundField',)
[docs]@html_safe
@python_2_unicode_compatible
class BoundField(object):
"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)
self.html_initial_name = form.add_initial_prefix(name)
self.html_initial_id = form.add_initial_prefix(self.auto_id)
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 __str__(self):
"""Renders this field as an HTML widget."""
if self.field.show_hidden_initial:
return self.as_widget() + self.as_hidden(only_initial=True)
return self.as_widget()
@cached_property
def subwidgets(self):
"""
Most widgets yield a single subwidget, but others like RadioSelect and
CheckboxSelectMultiple produce one subwidget for each choice.
This property is cached so that only one database query occurs when
rendering ModelChoiceFields.
"""
id_ = self.field.widget.attrs.get('id') or self.auto_id
attrs = {'id': id_} if id_ else {}
attrs = self.build_widget_attrs(attrs)
return list(
BoundWidget(self.field.widget, widget, self.form.renderer)
for widget in self.field.widget.subwidgets(self.html_name, self.value(), attrs=attrs)
)
def __bool__(self):
# BoundField evaluates to True even if it doesn't have subwidgets.
return True
def __nonzero__(self): # Python 2 compatibility
return type(self).__bool__(self)
def __iter__(self):
return iter(self.subwidgets)
def __len__(self):
return len(self.subwidgets)
def __getitem__(self, idx):
# Prevent unnecessary reevaluation when accessing BoundField's attrs
# from templates.
if not isinstance(idx, six.integer_types + (slice,)):
raise TypeError
return self.subwidgets[idx]
@property
def errors(self):
"""
Returns an ErrorList for this field. Returns an empty ErrorList
if there are none.
"""
return self.form.errors.get(self.name, self.form.error_class())
[docs] def as_widget(self, widget=None, attrs=None, only_initial=False):
"""
Renders the field by rendering the passed widget, adding any HTML
attributes passed as attrs. If no widget is specified, then the
field's default widget will be used.
"""
if not widget:
widget = self.field.widget
if self.field.localize:
widget.is_localized = True
attrs = attrs or {}
attrs = self.build_widget_attrs(attrs, widget)
auto_id = self.auto_id
if auto_id and 'id' not in attrs and 'id' not in widget.attrs:
if not only_initial:
attrs['id'] = auto_id
else:
attrs['id'] = self.html_initial_id
if not only_initial:
name = self.html_name
else:
name = self.html_initial_name
kwargs = {}
if func_supports_parameter(widget.render, 'renderer') or func_accepts_kwargs(widget.render):
kwargs['renderer'] = self.form.renderer
else:
warnings.warn(
'Add the `renderer` argument to the render() method of %s. '
'It will be mandatory in Django 2.1.' % widget.__class__,
RemovedInDjango21Warning, stacklevel=2,
)
html = widget.render(
name=name,
value=self.value(),
attrs=attrs,
**kwargs
)
return force_text(html)
def as_text(self, attrs=None, **kwargs):
"""
Returns a string of HTML for representing this as an <input type="text">.
"""
return self.as_widget(TextInput(), attrs, **kwargs)
def as_textarea(self, attrs=None, **kwargs):
"Returns a string of HTML for representing this as a <textarea>."
return self.as_widget(Textarea(), attrs, **kwargs)
@property
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.form.files, self.html_name)
[docs] def value(self):
"""
Returns the value for this BoundField, using the initial value if
the form is not bound or the data otherwise.
"""
data = self.initial
if self.form.is_bound:
data = self.field.bound_data(self.data, data)
return self.field.prepare_value(data)
[docs] def label_tag(self, contents=None, attrs=None, label_suffix=None):
"""
Wraps the given contents in a <label>, if the field has an ID attribute.
contents should be 'mark_safe'd to avoid HTML escaping. 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.
label_suffix allows overriding the form's label_suffix.
"""
contents = contents or self.label
if label_suffix is None:
label_suffix = (self.field.label_suffix if self.field.label_suffix is not None
else self.form.label_suffix)
# Only add the suffix if the label does not end in punctuation.
# Translators: If found as last label character, these punctuation
# characters will prevent the default label_suffix to be appended to the label
if label_suffix and contents and contents[-1] not in _(':?.!'):
contents = format_html('{}{}', contents, label_suffix)
widget = self.field.widget
id_ = widget.attrs.get('id') or self.auto_id
if id_:
id_for_label = widget.id_for_label(id_)
if id_for_label:
attrs = dict(attrs or {}, **{'for': id_for_label})
if self.field.required and hasattr(self.form, 'required_css_class'):
attrs = attrs or {}
if 'class' in attrs:
attrs['class'] += ' ' + self.form.required_css_class
else:
attrs['class'] = self.form.required_css_class
attrs = flatatt(attrs) if attrs else ''
contents = format_html('<label{}>{}</label>', attrs, contents)
else:
contents = conditional_escape(contents)
return mark_safe(contents)
[docs] def css_classes(self, extra_classes=None):
"""
Returns a string of space-separated CSS classes for this field.
"""
if hasattr(extra_classes, 'split'):
extra_classes = extra_classes.split()
extra_classes = set(extra_classes or [])
if self.errors and hasattr(self.form, 'error_css_class'):
extra_classes.add(self.form.error_css_class)
if self.field.required and hasattr(self.form, 'required_css_class'):
extra_classes.add(self.form.required_css_class)
return ' '.join(extra_classes)
@property
def is_hidden(self):
"Returns True if this BoundField's widget is hidden."
return self.field.widget.is_hidden
@property
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 force_text(auto_id):
return force_text(auto_id) % self.html_name
elif auto_id:
return self.html_name
return ''
@property
def id_for_label(self):
"""
Wrapper around the field widget's `id_for_label` method.
Useful, for example, for focusing on this field regardless of whether
it has a single widget or a MultiWidget.
"""
widget = self.field.widget
id_ = widget.attrs.get('id') or self.auto_id
return widget.id_for_label(id_)
@cached_property
def initial(self):
data = self.form.get_initial_for_field(self.field, self.name)
# If this is an auto-generated default date, nix the microseconds for
# standardized handling. See #22502.
if (isinstance(data, (datetime.datetime, datetime.time)) and
not self.field.widget.supports_microseconds):
data = data.replace(microsecond=0)
return data
def build_widget_attrs(self, attrs, widget=None):
if not widget:
widget = self.field.widget
attrs = dict(attrs) # Copy attrs to avoid modifying the argument.
if widget.use_required_attribute(self.initial) and self.field.required and self.form.use_required_attribute:
attrs['required'] = True
if self.field.disabled:
attrs['disabled'] = True
return attrs
@html_safe
@python_2_unicode_compatible
class BoundWidget(object):
"""
A container class used for iterating over widgets. This is useful for
widgets that have choices. For example, the following can be used in a
template:
{% for radio in myform.beatles %}
<label for="{{ radio.id_for_label }}">
{{ radio.choice_label }}
<span class="radio">{{ radio.tag }}</span>
</label>
{% endfor %}
"""
def __init__(self, parent_widget, data, renderer):
self.parent_widget = parent_widget
self.data = data
self.renderer = renderer
def __str__(self):
return self.tag(wrap_label=True)
def tag(self, wrap_label=False):
context = {'widget': self.data, 'wrap_label': wrap_label}
return self.parent_widget._render(self.template_name, context, self.renderer)
@property
def template_name(self):
if 'template_name' in self.data:
return self.data['template_name']
return self.parent_widget.template_name
@property
def id_for_label(self):
return 'id_%s_%s' % (self.data['name'], self.data['index'])
@property
def choice_label(self):
return self.data['label']
