212 lines
8.2 KiB
Python
212 lines
8.2 KiB
Python
"""
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HTML Widget classes
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"""
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__all__ = (
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'Widget', 'TextInput', 'PasswordInput', 'HiddenInput', 'FileInput',
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'Textarea', 'CheckboxInput',
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'Select', 'SelectMultiple', 'RadioSelect', 'CheckboxSelectMultiple',
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)
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from util import smart_unicode
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from django.utils.html import escape
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from itertools import chain
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try:
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set # Only available in Python 2.4+
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except NameError:
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from sets import Set as set # Python 2.3 fallback
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# Converts a dictionary to a single string with key="value", XML-style with
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# a leading space. Assumes keys do not need to be XML-escaped.
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flatatt = lambda attrs: u''.join([u' %s="%s"' % (k, escape(v)) for k, v in attrs.items()])
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class Widget(object):
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requires_data_list = False # Determines whether render()'s 'value' argument should be a list.
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def __init__(self, attrs=None):
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self.attrs = attrs or {}
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def render(self, name, value):
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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'] = smart_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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class HiddenInput(Input):
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input_type = 'hidden'
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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 render(self, name, value, attrs=None):
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if value is None: value = ''
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value = smart_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 render(self, name, value, attrs=None):
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final_attrs = self.build_attrs(attrs, type='checkbox', name=name)
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if value: final_attrs['checked'] = 'checked'
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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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# 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%s>' % flatatt(final_attrs)]
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str_value = smart_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 = smart_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(smart_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 SelectMultiple(Widget):
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requires_data_list = True
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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([smart_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 = smart_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(smart_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 RadioInput(object):
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"An object used by RadioFieldRenderer that represents a single <input type='radio'>."
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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, self.choice_label = choice
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self.index = index
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def __str__(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 == smart_unicode(self.choice_value)
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def tag(self):
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if self.attrs.has_key('id'):
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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(object):
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"An object used by RadioSelect to enable customization of radio widgets."
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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 __str__(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>' % w for w in self])
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class RadioSelect(Select):
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def render(self, name, value, attrs=None, choices=()):
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"Returns a RadioFieldRenderer instance rather than a Unicode string."
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if value is None: value = ''
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str_value = smart_unicode(value) # Normalize to string.
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attrs = attrs or {}
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return RadioFieldRenderer(name, str_value, attrs, list(chain(self.choices, choices)))
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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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final_attrs = self.build_attrs(attrs, name=name)
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output = [u'<ul>']
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str_values = set([smart_unicode(v) for v in value]) # Normalize to strings.
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cb = CheckboxInput(final_attrs)
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for option_value, option_label in chain(self.choices, choices):
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option_value = smart_unicode(option_value)
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field_name = name + option_value
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rendered_cb = cb.render(field_name, (option_value in str_values))
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output.append(u'<li><label>%s %s</label></li>' % (rendered_cb, escape(smart_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 value_from_datadict(self, data, name):
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data_list = [k for k, v in self.choices if data.get(name + k)]
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return data_list or None
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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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