############################################################################## # # Copyright (c) 2002 Zope Corporation 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. # ############################################################################## """Form utility functions In Zope 2's formulator, forms provide a basic mechanism for organizing collections of fields and providing user interfaces for them, especially editing interfaces. In Zope 3, formulator's forms are replaced by Schema (See zope.schema). In addition, the Formulator fields have been replaced by schema fields and form widgets. Schema fields just express the semantics of data values. They contain no presentation logic or parameters. Widgets are views on fields that take care of presentation. The widget view names represent styles that can be selected by applications to customise the presentation. There can also be custom widgets with specific parameters. This module provides some utility functions that provide some of the functionality of formulator forms that isn't handled by schema, fields, or widgets. $Id: utility.py 107385 2009-12-30 20:25:24Z faassen $ """ __docformat__ = 'restructuredtext' from zope import security from zope.security.proxy import Proxy from zope.proxy import isProxy from zope.interface.interfaces import IMethod from zope.security.interfaces import ForbiddenAttribute, Unauthorized from zope.formlib.interfaces import WidgetsError, MissingInputError from zope.formlib.interfaces import InputErrors from zope.formlib.interfaces import IInputWidget, IDisplayWidget # BBB from zope.formlib.utility import ( setUpWidget, setUpWidgets, applyWidgetsChanges, _fieldlist, no_value, _widgetHasStickyValue) def setUpEditWidgets(view, schema, source=None, prefix=None, ignoreStickyValues=False, names=None, context=None, degradeInput=False, degradeDisplay=False): """Sets up widgets to collect input on a view. See `setUpWidgets` for details on `view`, `schema`, `prefix`, `ignoreStickyValues`, `names`, and `context`. `source`, if specified, is an object from which initial widget values are read. If source is not specified, the view context is used as the source. `degradeInput` is a flag that changes the behavior when a user does not have permission to edit a field in the names. By default, the function raises Unauthorized. If degradeInput is True, the field is changed to an IDisplayWidget. `degradeDisplay` is a flag that changes the behavior when a user does not have permission to access a field in the names. By default, the function raises Unauthorized. If degradeDisplay is True, the field is removed from the form. Returns a list of names, equal to or a subset of the names that were supposed to be drawn, with uninitialized undrawn fields missing. """ if context is None: context = view.context if source is None: source = view.context security_proxied = isProxy(source, Proxy) res_names = [] for name, field in _fieldlist(names, schema): try: value = field.get(source) except ForbiddenAttribute: raise except AttributeError: value = no_value except Unauthorized: if degradeDisplay: continue else: raise if field.readonly: viewType = IDisplayWidget else: if security_proxied: is_accessor = IMethod.providedBy(field) if is_accessor: set_name = field.writer.__name__ authorized = security.canAccess(source, set_name) else: set_name = name authorized = security.canWrite(source, name) if not authorized: if degradeInput: viewType = IDisplayWidget else: raise Unauthorized(set_name) else: viewType = IInputWidget else: # if object is not security proxied, might be a standard # adapter without a registered checker. If the feature of # paying attention to the users ability to actually set a # field is decided to be a must-have for the form machinery, # then we ought to change this case to have a deprecation # warning. viewType = IInputWidget setUpWidget(view, name, field, viewType, value, prefix, ignoreStickyValues, context) res_names.append(name) return res_names def setUpDisplayWidgets(view, schema, source=None, prefix=None, ignoreStickyValues=False, names=None, context=None, degradeDisplay=False): """Sets up widgets to display field values on a view. See `setUpWidgets` for details on `view`, `schema`, `prefix`, `ignoreStickyValues`, `names`, and `context`. `source`, if specified, is an object from which initial widget values are read. If source is not specified, the view context is used as the source. `degradeDisplay` is a flag that changes the behavior when a user does not have permission to access a field in the names. By default, the function raises Unauthorized. If degradeDisplay is True, the field is removed from the form. Returns a list of names, equal to or a subset of the names that were supposed to be drawn, with uninitialized undrawn fields missing. """ if context is None: context = view.context if source is None: source = view.context res_names = [] for name, field in _fieldlist(names, schema): try: value = field.get(source) except ForbiddenAttribute: raise except AttributeError: value = no_value except Unauthorized: if degradeDisplay: continue else: raise setUpWidget(view, name, field, IDisplayWidget, value, prefix, ignoreStickyValues, context) res_names.append(name) return res_names def viewHasInput(view, schema, names=None): """Returns ``True`` if the any of the view's widgets contain user input. `schema` specifies the set of fields that correspond to the view widgets. `names` can be specified to provide a subset of these fields. """ for name, field in _fieldlist(names, schema): if getattr(view, name + '_widget').hasInput(): return True return False def getWidgetsData(view, schema, names=None): """Returns user entered data for a set of `schema` fields. The return value is a map of field names to data values. `view` is the view containing the widgets. `schema` is the schema that defines the widget fields. An optional `names` argument can be provided to specify an alternate list of field values to return. If `names` is not specified, or is ``None``, `getWidgetsData` will attempt to return values for all of the fields in the schema. A requested field value may be omitted from the result for one of two reasons: - The field is read only, in which case its widget will not have user input. - The field is editable and not required but its widget does not contain user input. If a field is required and its widget does not have input, `getWidgetsData` raises an error. A widget may raise a validation error if it cannot return a value that satisfies its field's contraints. Errors, if any, are collected for all fields and reraised as a single `WidgetsError`. """ result = {} errors = [] for name, field in _fieldlist(names, schema): widget = getattr(view, name + '_widget') if IInputWidget.providedBy(widget): if widget.hasInput(): try: result[name] = widget.getInputValue() except InputErrors, error: errors.append(error) elif field.required: errors.append(MissingInputError( name, widget.label, 'the field is required')) if errors: raise WidgetsError(errors, widgetsData=result) return result