Source code for zope.formlib.sequencewidget
##############################################################################
#
# Copyright (c) 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 widgets for sequences
"""
__docformat__ = 'restructuredtext'
from zope import component
from zope.interface import implementer
from zope.i18n import translate
from zope.schema.interfaces import ValidationError
from zope.formlib.interfaces import IDisplayWidget, IInputWidget
from zope.formlib.interfaces import WidgetInputError, MissingInputError
from zope.formlib.widget import InputWidget
from zope.formlib.i18n import _
from zope.formlib.widget import BrowserWidget
from zope.formlib.widget import DisplayWidget, renderElement
from zope.browserpage import ViewPageTemplateFile
[docs]@implementer(IInputWidget)
class SequenceWidget(BrowserWidget, InputWidget):
"""A widget baseclass for a sequence of fields.
subwidget - Optional CustomWidget used to generate widgets for the
items in the sequence
"""
template = ViewPageTemplateFile('sequencewidget.pt')
_type = tuple
def __init__(self, context, field, request, subwidget=None):
super(SequenceWidget, self).__init__(context, request)
self.subwidget = subwidget
# The subwidgets are cached in this dict if preserve_widgets is True.
self._widgets = {}
self.preserve_widgets = False
def __call__(self):
"""Render the widget"""
self._update()
return self.template()
def _update(self):
"""Set various attributes for the template"""
sequence = self._getRenderedValue()
num_items = len(sequence)
self.need_add = (not self.context.max_length
or num_items < self.context.max_length)
self.need_delete = num_items and num_items > self.context.min_length
self.marker = self._getPresenceMarker(num_items)
[docs] def widgets(self):
"""Return a list of widgets to display"""
sequence = self._getRenderedValue()
result = []
for i, value in enumerate(sequence):
widget = self._getWidget(i)
widget.setRenderedValue(value)
result.append(widget)
return result
def addButtonLabel(self):
button_label = _('Add %s')
button_label = translate(button_label, context=self.request,
default=button_label)
title = self.context.title or self.context.__name__
title = translate(title, context=self.request, default=title)
return button_label % title
def _getWidget(self, i):
"""Return a widget for the i-th number of the sequence.
Normally this method creates a new widget each time, but when
the ``preserve_widgets`` attribute is True, it starts caching
widgets. We need it so that the errors on the subwidgets
would appear only if ``getInputValue`` was called.
``getInputValue`` on the subwidgets gets called on each
request that has data.
"""
if i not in self._widgets:
field = self.context.value_type
if self.subwidget is not None:
widget = self.subwidget(field, self.request)
else:
widget = component.getMultiAdapter(
(field, self.request), IInputWidget)
widget.setPrefix('%s.%d.' % (self.name, i))
if not self.preserve_widgets:
return widget
self._widgets[i] = widget
return self._widgets[i]
def _getRenderedValue(self):
"""Returns a sequence from the request or _data"""
if self._renderedValueSet():
if self._data is self.context.missing_value:
sequence = []
else:
sequence = list(self._data)
elif self.hasInput():
sequence = self._generateSequence()
elif self.context.default is not None:
sequence = self.context.default
else:
sequence = []
# ensure minimum number of items in the form
while len(sequence) < self.context.min_length:
# Shouldn't this use self.field.value_type.missing_value,
# instead of None?
sequence.append(None)
return sequence
def _getPresenceMarker(self, count=0):
return ('<input type="hidden" name="%s.count" value="%d" />'
% (self.name, count))
[docs] def getInputValue(self):
"""Return converted and validated widget data.
If there is no user input and the field is required, then a
``MissingInputError`` will be raised.
If there is no user input and the field is not required, then
the field default value will be returned.
A ``WidgetInputError`` is raised in the case of one or more
errors encountered, inputting, converting, or validating the data.
"""
if self.hasInput():
self.preserve_widgets = True
sequence = self._type(self._generateSequence())
if sequence != self.context.missing_value:
# catch and set field errors to ``_error`` attribute
try:
self.context.validate(sequence)
except WidgetInputError as error:
self._error = error
raise self._error
except ValidationError as error:
self._error = WidgetInputError(
self.context.__name__, self.label, error)
raise self._error
elif self.context.required:
raise MissingInputError(self.context.__name__,
self.context.title)
return sequence
raise MissingInputError(self.context.__name__, self.context.title)
# TODO: applyChanges isn't reporting "change" correctly (we're
# re-generating the sequence with every edit, and need to be smarter)
def applyChanges(self, content):
field = self.context
value = self.getInputValue()
change = field.query(content, self) != value
if change:
field.set(content, value)
return change
[docs] def hasInput(self):
"""Is there input data for the field
Return ``True`` if there is data and ``False`` otherwise.
"""
return (self.name + ".count") in self.request.form
def _generateSequence(self):
"""Extract the values of the subwidgets from the request.
Returns a list of values.
This can only be called if self.hasInput() returns true.
"""
if self.context.value_type is None:
# Why would this ever happen?
return []
# the marker field tells how many individual items were
# included in the input; we check for exactly that many input
# widgets
try:
count = int(self.request.form[self.name + ".count"])
except ValueError:
# could not convert to int; the input was not generated
# from the widget as implemented here
raise WidgetInputError(self.context.__name__, self.context.title)
# pre-populate
sequence = [None] * count
# now look through the request for interesting values
# in reverse so that we can remove items as we go
removing = self.name + ".remove" in self.request.form
for i in reversed(list(range(count))):
widget = self._getWidget(i)
if widget.hasValidInput():
# catch and set sequence widget errors to ``_error`` attribute
try:
sequence[i] = widget.getInputValue()
except WidgetInputError as error:
self._error = error
raise self._error
remove_key = "%s.remove_%d" % (self.name, i)
if remove_key in self.request.form and removing:
del sequence[i]
# add an entry to the list if the add button has been pressed
if self.name + ".add" in self.request.form:
# Should this be using self.context.value_type.missing_value
# instead of None?
sequence.append(None)
return sequence
# Basic display widget
[docs]class SequenceDisplayWidget(DisplayWidget):
_missingValueMessage = _("sequence-value-not-provided",
u"(no value available)")
_emptySequenceMessage = _("sequence-value-is-empty",
u"(no values)")
tag = "ol"
itemTag = "li"
cssClass = "sequenceWidget"
extra = ""
def __init__(self, context, field, request, subwidget=None):
super(SequenceDisplayWidget, self).__init__(context, request)
self.subwidget = subwidget
def __call__(self):
# get the data to display:
if self._renderedValueSet():
data = self._data
else:
data = self.context.get(self.context.context)
# deal with special cases:
if data == self.context.missing_value:
return translate(self._missingValueMessage, self.request)
data = list(data)
if not data:
return translate(self._emptySequenceMessage, self.request)
parts = []
for i, item in enumerate(data):
widget = self._getWidget(i)
widget.setRenderedValue(item)
s = widget()
if self.itemTag:
s = "<%s>%s</%s>" % (self.itemTag, s, self.itemTag)
parts.append(s)
contents = "\n".join(parts)
if self.tag:
contents = "\n%s\n" % contents
contents = renderElement(self.tag,
cssClass=self.cssClass,
extra=self.extra,
contents=contents)
return contents
def _getWidget(self, i):
field = self.context.value_type
if self.subwidget is not None:
widget = self.subwidget(field, self.request)
else:
widget = component.getMultiAdapter(
(field, self.request), IDisplayWidget)
widget.setPrefix('%s.%d.' % (self.name, i))
return widget