Contents
plone.autoform
builds custom z3c.form forms based on a model (schema)
of what fields to include and what widgets and options should be used for each
field. This model is defined as a zope.schema-based schema, but additional
hints can be supplied to control aspects of form display not normally specified
in a Zope schema.
To use the automatic form setup, mix in the following base class in your forms:
>>> from plone.autoform.form import AutoExtensibleForm
and then provide the schema
(a schema interface) and optionally the
additionalSchemata
(a list of schema interfaces) attributes on your form:
class MyForm(AutoExtensibleForm, form.EditForm): schema = IMySchema additionalSchemata = (ISchemaOne, ISchemaTwo,) # ...
For dynamic forms, you could of course make schema
and
additionalSchemata
into properties. For example, plone.dexterity extends the
basic AutoExtensibleForm so that schema
is the content type schema and
additionalSchemata
is a list of field provider schemas associated with
behaviors.
Directives can be specified in the schema to control aspects of form presentation.
A field's widget can be displayed in several "modes":
- input - allows the user to enter data into the field
- display - a read-only indication of the field's value
- hidden - a record of the field's value that is included only in the HTML source
The mode can be controlled using the mode
directive:
from plone.supermodel import model from plone.autoform import directives as form class IMySchema(model.Schema): form.mode(secret='hidden') form.mode(IEditForm, secret='input') secret = schema.TextLine( title=u"Secret", default=u"Secret stuff (except on edit forms)" )
In this case the mode for the secret
field is set to 'hidden' for most forms,
but 'input' for forms that provide the IEditForm interface.
The corresponding supermodel XML directive is form:mode
:
<field type="zope.schema.TextLine" name="secret" form:mode="z3c.form.interfaces.IForm:hidden z3c.form.interfaces.IEditForm:input"> <title>Secret</title> <description>Secret stuff (except on edit forms)</description> </field>
The mode can be specified briefly if it should be the same for all forms:
<field type="zope.schema.TextLine" name="secret" form:mode="hidden"> <title>Secret</title> <description>Secret stuff</description> </field>
In other words, form:mode
may be either a single mode, or a space-separated
list of form_interface:mode pairs.
A field can be omitted entirely from all forms, or from some forms,
using the omitted
and no_omit
diretives. In this example,
the dummy
field is omitted from all forms, and the edit_only
field is omitted from all forms except those that provide the
IEditForm interface:
from z3c.form.interfaces import IEditForm from plone.supermodel import model from plone.autoform import directives as form class IMySchema(model.Schema): form.omitted('dummy') dummy = schema.Text( title=u"Dummy" ) form.omitted('edit_only') form.no_omit(IEditForm, 'edit_only') edit_only = schema.TextLine( title = u'Only included on edit forms', )
In supermodel XML, this can be specified as:
<field type="zope.schema.TextLine" name="dummy" form:omitted="true"> <title>Dummy</title> </field> <field type="zope.schema.TextLine" name="edit-only" form:omitted="z3c.form.interfaces.IForm:true z3c.form.interfaces.IEditForm:false"> <title>Only included on edit form</title> </field>
form:omitted
may be either a single boolean value, or a space-separated
list of form_interface:boolean pairs.
A field's position in the form can be influenced using the order_before
and order_after
directives. In this example, the not_last
field
is placed before the summary
field even though it is defined afterward:
from plone.supermodel import model from plone.autoform import directives as form class IMySchema(model.Schema): summary = schema.Text( title=u"Summary", description=u"Summary of the body", readonly=True ) form.order_before(not_last='summary') not_last = schema.TextLine( title=u"Not last", )
The value passed to the directive may be either '*' (indicating before or after
all fields) or the name of another field. Use '.fieldname'
to refer to field
in the current schema (or a base schema). Use a fully prefixed name (e.g.
'my.package.ISomeSchema'
) to refer to a field in another schema. Use an
unprefixed name to refer to a field in the default schema for the form.
In supermodel XML, the directives are called form:before
and form:after
.
For example:
<field type="zope.schema.TextLine" name="not_last" form:before="*"> <title>Not last</title> </field>
Fields can be grouped into fieldsets, which will be rendered within an HTML
<fieldset>
tag. In this example the footer
and dummy
fields
are placed within the extra
fieldset:
from plone.supermodel import model from plone.autoform import directives as form class IMySchema(model.Schema): model.fieldset('extra', label=u"Extra info", fields=['footer', 'dummy'] ) footer = schema.Text( title=u"Footer text", ) dummy = schema.Text( title=u"Dummy" )
In supermodel XML fieldsets are specified by grouping fields within a
<fieldset>
tag:
<fieldset name="extra" label="Extra info"> <field name="footer" type="zope.schema.TextLine"> <title>Footer text</title> </field> <field name="dummy" type="zope.schema.TextLine"> <title>Dummy</title> </field> </fieldset>
Usually, z3c.form picks a widget based on the type of your field.
You can change the widget using the widget
directive if you want
users to enter or view data in a different format. For example,
here we change the widget for the human
field to use yes/no
radio buttons instead of a checkbox:
from plone.supermodel import model from plone.autoform import directives as form from z3c.form.browser.radio import RadioFieldWidget class IMySchema(model.Schema): form.widget('human', RadioFieldWidget) human = schema.Bool( title = u'Are you human?', )
You can also pass widget parameters to control attributes of the widget. For example, here we keep the default widget, but set a CSS class:
from plone.supermodel import model from plone.autoform import directives as form from z3c.form.browser.radio import RadioWidget class IMySchema(model.Schema): form.widget('human', klass='annoying') human = schema.Bool( title = u'Are you human?', )
In supermodel XML the widget is specified using a <form:widget>
tag, which
can have its own elements specifying parameters:
<field name="human" type="zope.schema.TextLine"> <title>Are you human?</title> <form:widget type="z3c.form.browser.radio.RadioWidget"> <klass>annoying</klass> </form:widget> </field>
Note: In order to be included in the XML representation of a schema,
widget parameters must be handled by a WidgetExportImportHandler utility.
There is a default one which handles the attributes defined in
z3c.form.browser.interfaces.IHTMLFormElement
.
By default, fields are included in the form regardless of the user's
permissions. Fields can be protected using the read_permission
and write_permission
directives. The read permission is checked when
the field is in display mode, and the write permission is checked when
the field is in input mode. The permission should be given with its
Zope 3-style name (i.e. cmf.ManagePortal rather than 'Manage portal').
In this example, the secret
field is protected by the
cmf.ManagePortal
permission as both a read and write permission.
This means that in both display and input modes, the field will
only be included in the form for users who have that permission:
from plone.supermodel import model from plone.autoform import directives as form class IMySchema(model.Schema): form.read_permission('secret', 'cmf.ManagePortal') form.write_permission('secret', 'cmf.ManagePortal') secret = schema.TextLine( title = u'Secret', )
In supermodel XML the directives are security:read-permission
and
security:write-permission
:
<field type="zope.schema.TextLine" name="secret" security:read-permission="cmf.ManagePortal" security:write-permission="cmf.ManagePortal"> <title>Secret</title> </field>
Sometimes rather than rendering a form for data entry, you want to display stored values based on the same schema. This can be done using a "display form." The display form renders each field's widget in "display mode," which means that it shows the field value in read-only form rather than as a form input.
To use the display form, create a view that extends WidgetsView
like this:
>>> from plone.autoform.view import WidgetsView >>> class MyView(WidgetsView): ... schema = IMySchema ... additionalSchemata = (ISchemaOne, ISchemaTwo,) ... ... # ...
To render the form, do not override __call__()
. Instead, either implement
the render()
method, set an index
attribute to a page template or
other callable, or use the template
attribute of the <browser:page />
ZCML directive when registering the view.
In the template, you can use the following variables:
view/w
is a dictionary of all widgets, including those from non-default fieldsets (by contrast, thewidgets
variable contains only those widgets in the default fieldset). The keys are the field names, and the values are widget instances. To render a widget (in display mode), you can dotal:replace="structure view/w/myfield/render" />
.view/fieldsets
is a dictionary of all fieldsets (not including the default fieldset, i.e. those widgets not placed into a fieldset). They keys are the fieldset names, and the values are the fieldset form instances, which in turn have variables likewidgets
given a list of all widgets.
Zope schema fields do not allow storing arbitrary key-value data associated
with a particular field. However, arbitrary data can be stored in a
dictionary on the schema (interface) known as the "tagged values."
This is where plone.autoform
keeps track of its extra hints,
whether they are configured via Python directives, an XML model, or some
other way.
The tagged values are stored under various keys, which are defined
in the plone.autoform.interfaces
module. They can be set several ways:
- Manually, by using
setTaggedValue()
on an interface. - By loading the schema from a plone.supermodel XML file and using the
form:
prefix - By using the directives from
plone.autoform.directives
while defining a schema in Python.