Source code for zope.formlib.widget
##############################################################################
#
# Copyright (c) 2001-2004 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Browser Widget Definitions
"""
__docformat__ = 'restructuredtext'
import warnings
from xml.sax.saxutils import quoteattr, escape
from zope.component import getMultiAdapter
from zope.interface import implementer
from zope.schema.interfaces import ValidationError
from zope.publisher.browser import BrowserView
from zope.formlib.interfaces import ConversionError
from zope.formlib.interfaces import WidgetInputError, MissingInputError
from zope.formlib.interfaces import IBrowserWidget
from zope.formlib.interfaces import ISimpleInputWidget
from zope.formlib.interfaces import IWidgetInputErrorView
from zope.formlib.interfaces import IWidget, InputErrors, IWidgetFactory
from zope.formlib._compat import toUnicode
from zope.i18n import translate
from zope.schema.interfaces import IChoice, ICollection
if quoteattr("\r") != '"&13;"':
_quoteattr = quoteattr
def quoteattr(data):
return _quoteattr(
data, {'\n': ' ', '\r': ' ', '\t': '	'})
[docs]@implementer(IWidget)
class Widget(object):
"""Mixin class providing functionality common across widget types."""
_prefix = 'field.'
_data_marker = object()
_data = _data_marker
visible = True
def __init__(self, context, request):
self.context = context
self.request = request
self.name = self._prefix + context.__name__
self.label = self.context.title
self.hint = self.context.description
def _translate(self, text):
return translate(text, context=self.request, default=text)
def _renderedValueSet(self):
"""Returns ``True`` if the the widget's rendered value has been set.
This is a convenience method that widgets can use to check whether
or not `setRenderedValue` was called.
"""
return self._data is not self._data_marker
def setPrefix(self, prefix):
if prefix and not prefix.endswith("."):
prefix += '.'
self._prefix = prefix
self.name = prefix + self.context.__name__
def setRenderedValue(self, value):
self._data = value
[docs]class InputWidget(Widget):
"""Mixin class providing some default input widget methods."""
def hasValidInput(self):
try:
self.getInputValue()
return True
except InputErrors:
return False
def applyChanges(self, content):
field = self.context
value = self.getInputValue()
if field.query(content, self) != value:
field.set(content, value)
return True
else:
return False
[docs]@implementer(IWidgetFactory)
class CustomWidgetFactory(object):
"""Custom Widget Factory."""
def __init__(self, widget_factory, *args, **kw):
self._widget_factory = widget_factory
self.args = args
self.kw = kw
def _create(self, args):
instance = self._widget_factory(*args)
for name, value in self.kw.items():
setattr(instance, name, value)
return instance
def __call__(self, context, request):
# Sequence widget factory
if ICollection.providedBy(context):
args = (context, context.value_type, request) + self.args
# Vocabulary widget factory
elif IChoice.providedBy(context):
args = (context, context.vocabulary, request) + self.args
# Regular widget factory
else:
args = (context, request) + self.args
return self._create(args)
[docs]@implementer(IBrowserWidget)
class BrowserWidget(Widget, BrowserView):
"""Base class for browser widgets.
>>> setUp()
The class provides some basic functionality common to all browser widgets.
Browser widgets have a `required` attribute, which indicates whether or
not the underlying field requires input. By default, the widget's required
attribute is equal to the field's required attribute:
>>> from zope.schema import Field
>>> from zope.publisher.browser import TestRequest
>>> field = Field(required=True)
>>> widget = BrowserWidget(field, TestRequest())
>>> widget.required
True
>>> field.required = False
>>> widget = BrowserWidget(field, TestRequest())
>>> widget.required
False
However, the two `required` values are independent of one another:
>>> field.required = True
>>> widget.required
False
Browser widgets have an error state, which can be rendered in a form using
the `error()` method. The error method delegates the error rendering to a
view that is registered as providing `IWidgetInputErrorView`. To
illustrate, we can create and register a simple error display view:
>>> from zope.component import provideAdapter
>>> from zope.publisher.interfaces.browser import IDefaultBrowserLayer
>>> from zope.formlib.interfaces import IWidgetInputError
>>> @implementer(IWidgetInputErrorView)
... class SnippetErrorView:
... def __init__(self, context, request):
... self.context = context
... def snippet(self):
... return "The error: " + str(self.context.errors)
>>> provideAdapter(SnippetErrorView,
... (IWidgetInputError, IDefaultBrowserLayer),
... IWidgetInputErrorView, '')
Whever an error occurs, widgets should set _error:
>>> widget._error = WidgetInputError('foo', 'Foo', ('Err1', 'Err2'))
so that it can be displayed using the error() method:
>>> widget.error()
"The error: ('Err1', 'Err2')"
>>> tearDown()
"""
_error = None
def __init__(self, context, request):
super(BrowserWidget, self).__init__(context, request)
self.required = context.required
def error(self):
if self._error:
return getMultiAdapter((self._error, self.request),
IWidgetInputErrorView).snippet()
return ""
def hidden(self):
return ""
[docs]@implementer(ISimpleInputWidget)
class SimpleInputWidget(BrowserWidget, InputWidget):
"""A baseclass for simple HTML form widgets.
>>> setUp()
Simple input widgets read input from a browser form. To illustrate, we
will use a test request with two form values:
>>> from zope.publisher.browser import TestRequest
>>> request = TestRequest(form={
... 'field.foo': u'hello\\r\\nworld',
... 'baz.foo': u'bye world'})
Like all widgets, simple input widgets are a view to a field context:
>>> from zope.schema import Field
>>> field = Field(__name__='foo', title=u'Foo')
>>> widget = SimpleInputWidget(field, request)
Widgets are named using their field's name:
>>> widget.name
'field.foo'
The default implementation for the widget label is to use the field title:
>>> widget.label
u'Foo'
According the request, the widget has input because 'field.foo' is
present:
>>> widget.hasInput()
True
>>> widget.getInputValue()
u'hello\\r\\nworld'
Widgets maintain an error state, which is used to communicate invalid
input or other errors:
>>> widget._error is None
True
>>> widget.error()
''
`setRenderedValue` is used to specify the value displayed by the widget to
the user. This value, however, is not the same as the input value, which
is read from the request:
>>> widget.setRenderedValue('Hey\\nfolks')
>>> widget.getInputValue()
u'hello\\r\\nworld'
>>> widget._error is None
True
>>> widget.error()
''
You can use 'setPrefix' to remove or modify the prefix used to create the
widget name as follows:
>>> widget.setPrefix('')
>>> widget.name
'foo'
>>> widget.setPrefix('baz')
>>> widget.name
'baz.foo'
`getInputValue` always returns a value that can legally be assigned to
the widget field. To illustrate widget validation, we can add a constraint
to its field:
>>> import re
>>> field.constraint = re.compile('.*hello.*').match
Because we modified the widget's name, the widget will now read different
form input:
>>> request.form[widget.name]
u'bye world'
This input violates the new field constraint and therefore causes an
error when `getInputValue` is called:
>>> widget.getInputValue() #doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
WidgetInputError: ('foo', u'Foo', ConstraintNotSatisfied(u'bye world'))
Simple input widgets require that input be available in the form request.
If input is not present, a ``MissingInputError`` is raised:
>>> del request.form[widget.name]
>>> widget.getInputValue() #doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
MissingInputError: ('baz.foo', u'Foo', None)
A ``MissingInputError`` indicates that input is missing from the form
altogether. It does not indicate that the user failed to provide a value
for a required field. The ``MissingInputError`` above was caused by the
fact that the form does have any input for the widget:
>>> request.form[widget.name] #doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
KeyError: 'baz.foo'
If a user fails to provide input for a field, the form will contain the
input provided by the user, namely an empty string:
>>> request.form[widget.name] = ''
In such a case, if the field is required, a ``WidgetInputError`` will be
raised on a call to `getInputValue`:
>>> field.required = True
>>> widget.getInputValue() #doctest: +IGNORE_EXCEPTION_DETAIL
Traceback (most recent call last):
WidgetInputError: ('foo', u'Foo', RequiredMissing('foo'))
However, if the field is not required, the empty string will be converted
by the widget into the field's `missing_value` and read as a legal field
value:
>>> field.required = False
>>> widget.getInputValue() is field.missing_value
True
Another type of exception is a conversion error. It is raised when a value
cannot be converted to the desired Python object. Here is an example of a
floating point.
>>> from zope.schema import Float
>>> field = Float(__name__='price', title=u'Price')
>>> from zope.formlib.interfaces import ConversionError
>>> class FloatWidget(SimpleInputWidget):
... def _toFieldValue(self, input):
... try:
... return float(input)
... except ValueError as v:
... raise ConversionError('Invalid floating point data', v)
...
... def _toFormValue(self, value):
... value = super(FloatWidget, self)._toFormValue(value)
... return '%.2f' % value
>>> request = TestRequest(form={'field.price': u'32.0'})
>>> widget = FloatWidget(field, request)
>>> widget.getInputValue()
32.0
>>> widget()
u'<input class="textType" id="field.price" name="field.price" required="True" type="text" value="32.00" />'
>>> request = TestRequest(form={'field.price': u'<p>foo</p>'})
>>> widget = FloatWidget(field, request)
>>> try:
... widget.getInputValue()
... except ConversionError as error:
... print(error.doc())
Invalid floating point data
>>> widget()
u'<input class="textType" id="field.price" name="field.price" required="True" type="text" value="<p>foo</p>" />'
>>> tearDown()
""" # noqa: E501 line too long
tag = u'input'
type = u'text'
cssClass = u''
extra = u''
_missing = u''
[docs] def hasInput(self):
"""See IWidget.hasInput.
Returns ``True`` if the submitted request form contains a value for
the widget, otherwise returns False.
Some browser widgets may need to implement a more sophisticated test
for input. E.g. checkbox values are not supplied in submitted
forms when their value is 'off' -- in this case the widget will
need to add a hidden element to signal its presence in the form.
"""
return self.name in self.request.form
def getInputValue(self):
self._error = None
field = self.context
# form input is required, otherwise raise an error
if not self.hasInput():
raise MissingInputError(self.name, self.label, None)
# convert input to suitable value - may raise conversion error
try:
value = self._toFieldValue(self._getFormInput())
except ConversionError as error:
# ConversionError is already a WidgetInputError
self._error = error
raise self._error
# allow missing values only for non-required fields
if value == field.missing_value and not field.required:
return value
# value must be valid per the field constraints
try:
field.validate(value)
except ValidationError as v:
self._error = WidgetInputError(
self.context.__name__, self.label, v)
raise self._error
return value
def _getFormInput(self):
"""Returns current form input.
The value returned must be in a format that can be used as the 'input'
argument to `_toFieldValue`.
The default implementation returns the form value that corresponds to
the widget's name. Subclasses may override this method if their form
input consists of more than one form element or use an alternative
naming convention.
"""
return self.request.get(self.name)
def _toFieldValue(self, input):
"""Converts input to a value appropriate for the field type.
Widgets for non-string fields should override this method to
perform an appropriate conversion.
This method is used by getInputValue to perform the conversion
of form input (provided by `_getFormInput`) to an appropriate field
value.
"""
if input == self._missing:
return self.context.missing_value
else:
return input
def _toFormValue(self, value):
"""Converts a field value to a string used as an HTML form value.
This method is used in the default rendering of widgets that can
represent their values in a single HTML form value. Widgets whose
fields have more complex data structures should disregard this
method and override the default rendering method (__call__).
"""
if value == self.context.missing_value:
return self._missing
else:
return value
def _getCurrentValueHelper(self):
"""Helper to get the current input value.
Raises InputErrors if the data could not be validated/converted.
"""
input_value = None
if self._renderedValueSet():
input_value = self._data
else:
if self.hasInput():
# It's insane to use getInputValue this way. It can
# cause _error to get set spuriously. We'll work
# around this by saving and restoring _error if
# necessary.
error = self._error
try:
input_value = self.getInputValue()
finally:
self._error = error
else:
input_value = self._getDefault()
return input_value
def _getCurrentValue(self):
"""Returns the current input value.
Returns None if the data could not be validated/converted.
"""
try:
input_value = self._getCurrentValueHelper()
except InputErrors:
input_value = None
return input_value
def _getFormValue(self):
"""Returns a value suitable for use in an HTML form.
Detects the status of the widget and selects either the input value
that came from the request, the value from the _data attribute or the
default value.
"""
try:
input_value = self._getCurrentValueHelper()
except InputErrors:
form_value = self.request.form.get(self.name, self._missing)
else:
form_value = self._toFormValue(input_value)
return form_value
def _getDefault(self):
"""Returns the default value for this widget."""
return self.context.default
def __call__(self):
return renderElement(self.tag,
type=self.type,
name=self.name,
id=self.name,
value=self._getFormValue(),
cssClass=self.cssClass,
required=self.required,
extra=self.extra)
def hidden(self):
return renderElement(self.tag,
type='hidden',
name=self.name,
id=self.name,
value=self._getFormValue(),
cssClass=self.cssClass,
extra=self.extra)
[docs]class DisplayWidget(BrowserWidget):
def __init__(self, context, request):
super(DisplayWidget, self).__init__(context, request)
self.required = False
def __call__(self):
if self._renderedValueSet():
value = self._data
else:
value = self.context.default
if value == self.context.missing_value:
return ""
return escape(value)
[docs]class UnicodeDisplayWidget(DisplayWidget):
"""Display widget that converts the value to unicode before display."""
def __call__(self):
if self._renderedValueSet():
value = self._data
else:
value = self.context.default
if value == self.context.missing_value:
return ""
return escape(toUnicode(value))
[docs]def renderTag(tag, **kw):
"""Render the tag. Well, not all of it, as we may want to / it."""
attr_list = []
# special case handling for cssClass
cssClass = kw.pop('cssClass', u'')
# If the 'type' attribute is given, append this plus 'Type' as a
# css class. This allows us to do subselector stuff in css without
# necessarily having a browser that supports css subselectors.
# This is important if you want to style radio inputs differently than
# text inputs.
cssWidgetType = kw.get('type', u'')
if cssWidgetType:
cssWidgetType += u'Type'
names = [c for c in (cssClass, cssWidgetType) if c]
if names:
attr_list.append(u'class="%s"' % u' '.join(names))
style = kw.pop('style', u'')
if style:
attr_list.append(u'style=%s' % quoteattr(style))
# special case handling for extra 'raw' code
if 'extra' in kw:
# could be empty string but we don't care
extra = u" " + kw.pop('extra')
else:
extra = u''
# handle other attributes
if kw:
items = sorted(kw.items())
for key, value in items:
if value is None:
warnings.warn(
"None was passed for attribute %r. Passing None "
"as attribute values to renderTag is deprecated. "
"Passing None as an attribute value will be disallowed "
"starting in Zope 3.3."
% key,
DeprecationWarning, stacklevel=2)
value = key
attr_list.append(u'%s=%s' % (key, quoteattr(toUnicode(value))))
if attr_list:
attr_str = u" ".join(attr_list)
return u"<%s %s%s" % (tag, attr_str, extra)
else:
return u"<%s%s" % (tag, extra)
def renderElement(tag, **kw):
contents = kw.pop('contents', None)
if contents is not None:
# Do not quote contents, since it often contains generated HTML.
return u"%s>%s</%s>" % (renderTag(tag, **kw), contents, tag)
else:
return renderTag(tag, **kw) + " />"
def setUp():
import zope.component.testing
global setUp
setUp = zope.component.testing.setUp
setUp()
def tearDown():
import zope.component.testing
global tearDown
tearDown = zope.component.testing.tearDown
tearDown()