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.
"""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._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 = 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 = kw def _create(self, args): instance = self._widget_factory(*args) for name, value in 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={ ... '': u'hello\\r\\nworld', ... '': 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: >>> '' 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 '' 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('') >>> 'foo' >>> widget.setPrefix('baz') >>> '' `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[] 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.getInputValue() #doctest: +IGNORE_EXCEPTION_DETAIL Traceback (most recent call last): MissingInputError: ('', 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[] #doctest: +IGNORE_EXCEPTION_DETAIL Traceback (most recent call last): KeyError: '' 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[] = '' 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="&lt;p&gt;foo&lt;/p&gt;" />' >>> 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 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.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( 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._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,,, value=self._getFormValue(), cssClass=self.cssClass, required=self.required, extra=self.extra) def hidden(self): return renderElement(self.tag, type='hidden',,, 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()