413 lines
16 KiB
Python
413 lines
16 KiB
Python
"""
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HTML Widget classes
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"""
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try:
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set
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except NameError:
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from sets import Set as set # Python 2.3 fallback
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from itertools import chain
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from django.utils.datastructures import MultiValueDict
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from django.utils.html import escape
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from django.utils.translation import ugettext
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from django.utils.encoding import StrAndUnicode, force_unicode
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from util import flatatt
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__all__ = (
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'Widget', 'TextInput', 'PasswordInput',
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'HiddenInput', 'MultipleHiddenInput',
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'FileInput', 'Textarea', 'CheckboxInput',
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'Select', 'NullBooleanSelect', 'SelectMultiple', 'RadioSelect',
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'CheckboxSelectMultiple', 'MultiWidget', 'SplitDateTimeWidget',
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)
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class Widget(object):
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is_hidden = False # Determines whether this corresponds to an <input type="hidden">.
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def __init__(self, attrs=None):
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if attrs is not None:
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self.attrs = attrs.copy()
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else:
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self.attrs = {}
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def render(self, name, value, attrs=None):
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"""
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Returns this Widget rendered as HTML, as a Unicode string.
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The 'value' given is not guaranteed to be valid input, so subclass
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implementations should program defensively.
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"""
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raise NotImplementedError
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def build_attrs(self, extra_attrs=None, **kwargs):
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"Helper function for building an attribute dictionary."
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attrs = dict(self.attrs, **kwargs)
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if extra_attrs:
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attrs.update(extra_attrs)
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return attrs
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def value_from_datadict(self, data, name):
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"""
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Given a dictionary of data and this widget's name, returns the value
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of this widget. Returns None if it's not provided.
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"""
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return data.get(name, None)
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def id_for_label(self, id_):
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"""
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Returns the HTML ID attribute of this Widget for use by a <label>,
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given the ID of the field. Returns None if no ID is available.
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This hook is necessary because some widgets have multiple HTML
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elements and, thus, multiple IDs. In that case, this method should
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return an ID value that corresponds to the first ID in the widget's
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tags.
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"""
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return id_
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id_for_label = classmethod(id_for_label)
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class Input(Widget):
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"""
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Base class for all <input> widgets (except type='checkbox' and
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type='radio', which are special).
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"""
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input_type = None # Subclasses must define this.
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def render(self, name, value, attrs=None):
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if value is None: value = ''
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final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)
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if value != '': final_attrs['value'] = force_unicode(value) # Only add the 'value' attribute if a value is non-empty.
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return u'<input%s />' % flatatt(final_attrs)
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class TextInput(Input):
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input_type = 'text'
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class PasswordInput(Input):
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input_type = 'password'
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def __init__(self, attrs=None, render_value=True):
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self.attrs = attrs or {}
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self.render_value = render_value
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def render(self, name, value, attrs=None):
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if not self.render_value: value=None
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return super(PasswordInput, self).render(name, value, attrs)
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class HiddenInput(Input):
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input_type = 'hidden'
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is_hidden = True
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class MultipleHiddenInput(HiddenInput):
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"""
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A widget that handles <input type="hidden"> for fields that have a list
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of values.
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"""
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def __init__(self, attrs=None, choices=()):
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# choices can be any iterable
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self.attrs = attrs or {}
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self.choices = choices
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def render(self, name, value, attrs=None, choices=()):
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if value is None: value = []
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final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)
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return u'\n'.join([(u'<input%s />' % flatatt(dict(value=force_unicode(v), **final_attrs))) for v in value])
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def value_from_datadict(self, data, name):
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if isinstance(data, MultiValueDict):
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return data.getlist(name)
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return data.get(name, None)
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class FileInput(Input):
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input_type = 'file'
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class Textarea(Widget):
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def __init__(self, attrs=None):
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# The 'rows' and 'cols' attributes are required for HTML correctness.
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self.attrs = {'cols': '40', 'rows': '10'}
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if attrs:
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self.attrs.update(attrs)
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def render(self, name, value, attrs=None):
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if value is None: value = ''
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value = force_unicode(value)
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final_attrs = self.build_attrs(attrs, name=name)
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return u'<textarea%s>%s</textarea>' % (flatatt(final_attrs), escape(value))
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class CheckboxInput(Widget):
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def __init__(self, attrs=None, check_test=bool):
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# check_test is a callable that takes a value and returns True
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# if the checkbox should be checked for that value.
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self.attrs = attrs or {}
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self.check_test = check_test
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def render(self, name, value, attrs=None):
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final_attrs = self.build_attrs(attrs, type='checkbox', name=name)
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try:
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result = self.check_test(value)
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except: # Silently catch exceptions
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result = False
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if result:
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final_attrs['checked'] = 'checked'
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if value not in ('', True, False, None):
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final_attrs['value'] = force_unicode(value) # Only add the 'value' attribute if a value is non-empty.
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return u'<input%s />' % flatatt(final_attrs)
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class Select(Widget):
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def __init__(self, attrs=None, choices=()):
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self.attrs = attrs or {}
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# choices can be any iterable, but we may need to render this widget
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# multiple times. Thus, collapse it into a list so it can be consumed
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# more than once.
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self.choices = list(choices)
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def render(self, name, value, attrs=None, choices=()):
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if value is None: value = ''
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final_attrs = self.build_attrs(attrs, name=name)
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output = [u'<select%s>' % flatatt(final_attrs)]
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str_value = force_unicode(value) # Normalize to string.
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for option_value, option_label in chain(self.choices, choices):
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option_value = force_unicode(option_value)
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selected_html = (option_value == str_value) and u' selected="selected"' or ''
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output.append(u'<option value="%s"%s>%s</option>' % (escape(option_value), selected_html, escape(force_unicode(option_label))))
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output.append(u'</select>')
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return u'\n'.join(output)
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class NullBooleanSelect(Select):
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"""
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A Select Widget intended to be used with NullBooleanField.
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"""
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def __init__(self, attrs=None):
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choices = ((u'1', ugettext('Unknown')), (u'2', ugettext('Yes')), (u'3', ugettext('No')))
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super(NullBooleanSelect, self).__init__(attrs, choices)
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def render(self, name, value, attrs=None, choices=()):
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try:
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value = {True: u'2', False: u'3', u'2': u'2', u'3': u'3'}[value]
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except KeyError:
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value = u'1'
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return super(NullBooleanSelect, self).render(name, value, attrs, choices)
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def value_from_datadict(self, data, name):
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value = data.get(name, None)
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return {u'2': True, u'3': False, True: True, False: False}.get(value, None)
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class SelectMultiple(Widget):
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def __init__(self, attrs=None, choices=()):
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# choices can be any iterable
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self.attrs = attrs or {}
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self.choices = choices
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def render(self, name, value, attrs=None, choices=()):
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if value is None: value = []
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final_attrs = self.build_attrs(attrs, name=name)
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output = [u'<select multiple="multiple"%s>' % flatatt(final_attrs)]
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str_values = set([force_unicode(v) for v in value]) # Normalize to strings.
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for option_value, option_label in chain(self.choices, choices):
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option_value = force_unicode(option_value)
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selected_html = (option_value in str_values) and ' selected="selected"' or ''
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output.append(u'<option value="%s"%s>%s</option>' % (escape(option_value), selected_html, escape(force_unicode(option_label))))
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output.append(u'</select>')
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return u'\n'.join(output)
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def value_from_datadict(self, data, name):
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if isinstance(data, MultiValueDict):
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return data.getlist(name)
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return data.get(name, None)
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class RadioInput(StrAndUnicode):
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"""
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An object used by RadioFieldRenderer that represents a single
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<input type='radio'>.
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"""
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def __init__(self, name, value, attrs, choice, index):
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self.name, self.value = name, value
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self.attrs = attrs
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self.choice_value = force_unicode(choice[0])
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self.choice_label = force_unicode(choice[1])
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self.index = index
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def __unicode__(self):
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return u'<label>%s %s</label>' % (self.tag(), self.choice_label)
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def is_checked(self):
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return self.value == self.choice_value
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def tag(self):
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if 'id' in self.attrs:
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self.attrs['id'] = '%s_%s' % (self.attrs['id'], self.index)
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final_attrs = dict(self.attrs, type='radio', name=self.name, value=self.choice_value)
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if self.is_checked():
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final_attrs['checked'] = 'checked'
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return u'<input%s />' % flatatt(final_attrs)
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class RadioFieldRenderer(StrAndUnicode):
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"""
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An object used by RadioSelect to enable customization of radio widgets.
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"""
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def __init__(self, name, value, attrs, choices):
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self.name, self.value, self.attrs = name, value, attrs
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self.choices = choices
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def __iter__(self):
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for i, choice in enumerate(self.choices):
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yield RadioInput(self.name, self.value, self.attrs.copy(), choice, i)
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def __getitem__(self, idx):
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choice = self.choices[idx] # Let the IndexError propogate
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return RadioInput(self.name, self.value, self.attrs.copy(), choice, idx)
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def __unicode__(self):
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return self.render()
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def render(self):
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"""Outputs a <ul> for this set of radio fields."""
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return u'<ul>\n%s\n</ul>' % u'\n'.join([u'<li>%s</li>' % force_unicode(w) for w in self])
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class RadioSelect(Select):
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def __init__(self, *args, **kwargs):
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self.renderer = kwargs.pop('renderer', None)
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if not self.renderer:
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self.renderer = RadioFieldRenderer
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super(RadioSelect, self).__init__(*args, **kwargs)
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def get_renderer(self, name, value, attrs=None, choices=()):
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"""Returns an instance of the renderer."""
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if value is None: value = ''
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str_value = force_unicode(value) # Normalize to string.
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final_attrs = self.build_attrs(attrs)
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choices = list(chain(self.choices, choices))
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return self.renderer(name, str_value, final_attrs, choices)
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def render(self, name, value, attrs=None, choices=()):
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return self.get_renderer(name, value, attrs, choices).render()
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def id_for_label(self, id_):
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# RadioSelect is represented by multiple <input type="radio"> fields,
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# each of which has a distinct ID. The IDs are made distinct by a "_X"
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# suffix, where X is the zero-based index of the radio field. Thus,
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# the label for a RadioSelect should reference the first one ('_0').
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if id_:
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id_ += '_0'
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return id_
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id_for_label = classmethod(id_for_label)
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class CheckboxSelectMultiple(SelectMultiple):
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def render(self, name, value, attrs=None, choices=()):
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if value is None: value = []
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has_id = attrs and 'id' in attrs
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final_attrs = self.build_attrs(attrs, name=name)
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output = [u'<ul>']
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str_values = set([force_unicode(v) for v in value]) # Normalize to strings.
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for i, (option_value, option_label) in enumerate(chain(self.choices, choices)):
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# If an ID attribute was given, add a numeric index as a suffix,
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# so that the checkboxes don't all have the same ID attribute.
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if has_id:
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final_attrs = dict(final_attrs, id='%s_%s' % (attrs['id'], i))
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cb = CheckboxInput(final_attrs, check_test=lambda value: value in str_values)
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option_value = force_unicode(option_value)
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rendered_cb = cb.render(name, option_value)
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output.append(u'<li><label>%s %s</label></li>' % (rendered_cb, escape(force_unicode(option_label))))
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output.append(u'</ul>')
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return u'\n'.join(output)
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def id_for_label(self, id_):
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# See the comment for RadioSelect.id_for_label()
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if id_:
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id_ += '_0'
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return id_
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id_for_label = classmethod(id_for_label)
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class MultiWidget(Widget):
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"""
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A widget that is composed of multiple widgets.
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Its render() method is different than other widgets', because it has to
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figure out how to split a single value for display in multiple widgets.
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The ``value`` argument can be one of two things:
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* A list.
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* A normal value (e.g., a string) that has been "compressed" from
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a list of values.
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In the second case -- i.e., if the value is NOT a list -- render() will
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first "decompress" the value into a list before rendering it. It does so by
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calling the decompress() method, which MultiWidget subclasses must
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implement. This method takes a single "compressed" value and returns a
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list.
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When render() does its HTML rendering, each value in the list is rendered
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with the corresponding widget -- the first value is rendered in the first
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widget, the second value is rendered in the second widget, etc.
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Subclasses may implement format_output(), which takes the list of rendered
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widgets and returns a string of HTML that formats them any way you'd like.
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You'll probably want to use this class with MultiValueField.
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"""
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def __init__(self, widgets, attrs=None):
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self.widgets = [isinstance(w, type) and w() or w for w in widgets]
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super(MultiWidget, self).__init__(attrs)
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def render(self, name, value, attrs=None):
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# value is a list of values, each corresponding to a widget
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# in self.widgets.
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if not isinstance(value, list):
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value = self.decompress(value)
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output = []
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final_attrs = self.build_attrs(attrs)
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id_ = final_attrs.get('id', None)
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for i, widget in enumerate(self.widgets):
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try:
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widget_value = value[i]
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except IndexError:
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widget_value = None
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if id_:
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final_attrs = dict(final_attrs, id='%s_%s' % (id_, i))
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output.append(widget.render(name + '_%s' % i, widget_value, final_attrs))
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return self.format_output(output)
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def id_for_label(self, id_):
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# See the comment for RadioSelect.id_for_label()
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if id_:
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id_ += '_0'
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return id_
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id_for_label = classmethod(id_for_label)
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def value_from_datadict(self, data, name):
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return [widget.value_from_datadict(data, name + '_%s' % i) for i, widget in enumerate(self.widgets)]
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def format_output(self, rendered_widgets):
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"""
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Given a list of rendered widgets (as strings), returns a Unicode string
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representing the HTML for the whole lot.
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This hook allows you to format the HTML design of the widgets, if
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needed.
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"""
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return u''.join(rendered_widgets)
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def decompress(self, value):
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"""
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Returns a list of decompressed values for the given compressed value.
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The given value can be assumed to be valid, but not necessarily
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non-empty.
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"""
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raise NotImplementedError('Subclasses must implement this method.')
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class SplitDateTimeWidget(MultiWidget):
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"""
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A Widget that splits datetime input into two <input type="text"> boxes.
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"""
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def __init__(self, attrs=None):
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widgets = (TextInput(attrs=attrs), TextInput(attrs=attrs))
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super(SplitDateTimeWidget, self).__init__(widgets, attrs)
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def decompress(self, value):
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if value:
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return [value.date(), value.time()]
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return [None, None]
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