Metadata-Version: 1.0
Name: plone.directives.form
Version: 1.1
Summary: Grok-like directives configuring forms
Home-page: http://code.google.com/p/dexterity
Author: Martin Aspeli
Author-email: optilude@gmail.com
License: GPL
Description: =====================
        plone.directives.form
        =====================
        
        This package provides optional, Grok-like directives for configuring
        forms, as defined by the `z3c.form`_ library, using XML schemata as defined by
        `plone.supermodel`_ and/or using widget form layout as defined by
        `plone.autoform`_. It depends on `five.grok`_, which in turn depends on the
        various re-usable grokcore.* packages, but not Grok itself.
        
        .. contents:: Contents
        
        Installation
        ------------
        
        To use this package you must first install it, either by depending on it
        in your own ``setup.py`` (under the ``install_requires`` list), or by adding
        it directly to your buildout.
        
        This will pull in a number of dependencies. You probably want to pin those
        down to known-good versions by using a known-good version set. See the
        installation instructions of `five.grok`_ for a starting point.
        
        You must also load the relevant configuration from ``meta.zcml`` and
        ``configure.zcml``. For example, you could use statements like the following
        in your ``configure.zcml``::
        
            <include package="plone.directives.form" file="meta.zcml" />
            <include package="plone.directives.form" />
            
        or if you declare dependencies in setup.py using install_requires::
        
            <includeDependencies package="." />
                
        Schemata loaded from XML
        ------------------------
        
        ``plone.directives.form`` used to contain a directive for loading an XML-based
        schema model into a Python interface.  This directive has moved to ``plone.supermodel``, as ``plone.supermodel.model.load``.
        
        Form widget hints
        -----------------
        
        ``plone.directives.form`` used to contain a number of directives for generating
        a form from a schema, using hints stored in tagged values on that schema to
        control the form's layout and field widgets. These directives have now moved
        to other packages to avoid a dependency of Dexterity on grok.
        
        The ``fieldset`` and ``primary`` directives are now in 
        ``plone.supermodel.model``.
        
        The ``omitted``, ``no_omit``, ``mode``, ``widget``, ``order_before``,
        ``order_after``, ``read_permission``, and ``write_permission`` directives are
        now in ``plone.autoform.directives``.
        
        Value adapters
        --------------
        
        z3c.form has the concept of a "value adapter", a component that can provide
        a value for an attribute (usually of widgets and buttons) at runtime. This
        package comes with some helpful decorators to register value adapters for
        computed values. For example::
        
            from plone.directives import form
            from zope import schema
            
            class IMySchema(form.Schema):
            
                title = schema.TextLine(title=u"Title")
        
            @form.default_value(field=IMySchema['title'])
            def default_title(data):
                return data.context.suggested_title
                
        The decorator takes one or more discriminators. The available discriminators
        for ``default_value`` are:
        
        context
          The type of context (e.g. an interface)
        
        request
          The type of request (e.g. a layer marker interface). You can
          use 'layer' as an alias for 'request', but note that the data passed
          to the function will have a 'request' attribute only.
        
        view
            The type of form (e.g. a form instance or interface). You can
            use 'form' as an alias for 'view', but note that the data passed to
            the function will have 'view' attribute only.
        
        field
            The field instance (or a field interface).
        
        widget
            The widget type (e.g. an interface).
            
        You must specify either ``field`` or ``widget``. The object passed to the
        decorated function has an attribute for each discriminator.
        
        There are two more decorators:
        
        widget_label
          Provide a dynamic label for a widget. Takes the same discriminators as the
          ``default_value`` decorator.
          
        button_label -- Provide a dynamic label for a button. Takes parameters
          content (alias context), request (alias layer), form (alias view),
          manager and button.
        
        Please note the rather unfortunate differences in naming between the button 
        descriptors (content vs. context, form vs. view) and the widget ones. The
        descriptor will accept the same names, but the data object passed to the
        function will only contain the names as defined in z3c.form, so be careful.
        
        Validators
        ----------
        
        By default, z3c.form uses fields' native validation, as implemented by the
        ``IField.validate()`` method, as well as field constraints (functions passed
        as the ``constraint`` parameter to fields) and schema invariants (using the
        ``@zope.interface.invariant`` decorator in a schema interface). In addition,
        you can define your own widget validators (for an individual field of the
        form) and widget manager validators (which cover the entire form). This is
        useful if you do not want to define a validator on the schema, e.g. because
        the schema is also used elsewhere, or if you want to create a more generic
        validator that is applied to any fields that match its discriminators.
        
        This package provides a grokked decorator which you can use to define a simple
        widget validator, called ``@form.validator()``::
        
            from plone.directives import form
            from zope import schema
            
            class IMySchema(form.Schema):
            
                title = schema.TextLine(title=u"Title")
            
            @form.validator(field=IMySchema['title'])
            def validateTitle(value):
                if value == value.upper():
                    raise schema.ValidationError(u"Please don't shout")
        
        The validator should return nothing if the field is valid, or raise an
        ``zope.schema.ValidationError`` exception with an error message.
        
        The ``@form.validator()`` decorator can take various keyword arguments that
        determine when the validator is invoked. These are:
        
        context
          The type of context (e.g. an interface)
        
        request
          The type of request (e.g. a layer marker interface).
        
        view
            The type of form (e.g. a form instance or interface).
        
        field
            The field instance (or a field interface).
        
        widget
            The widget type (e.g. an interface).
        
        Note that this validator function does not give access to the full context
        of the standard validator, such as the field, widget, context or request.
        If you need that, you can create a standard validator adapter, e.g. using
        ``grok.Adapter``. See the `z3c.form`_ documentation for details.
        
        Also note that the standard field validator will be called before the custom
        validator is invoked. If you need to override the validator wholesale, you
        can again do so with a custom adapter.
        
        Error messages
        --------------
        
        When using custom validators, it is easy to supply a tailored error message.
        However, the error messages that arise from the default field validation
        mechanism (e.g. when a required field is omitted) are by necessity more
        generic. Sometimes, it may be necessary to override these messages to make
        them more user friendly.
        
        To customise an error message, you can use the ``@form.error_message`` grokked
        decorator. For example::
        
            from plone.directives import form
            from zope import schema
            
            from zope.schema.interfaces import TooShort
            
            class IMySchema(form.Schema):
            
                title = schema.TextLine(title=u"Title", min_length=2)
            
            @form.error_message(error=TooShort, field=IMySchema['title'])
            def titleTooShort(value):
                return u"The title '%s' is too short" % value
        
        The decorated function will be called when constructing an error message for
        the given field. It should return a unicode string or translatable message.
        The value passed is the value that failed validation.
        
        The ``@form.error_message`` validator takes keyword arguments that determine
        when the message is used. It is possible to register a generic error message
        for a given type of error that applies to all fields, or, as shown above,
        a message specific to an individual field and error. The latter is more
        common. In general, you should be careful if you omit either or both of the
        ``error`` and ``field`` discriminators.
        
        error
            An exception class that represents the error. All errors inherit from
            ``zope.interface.Invalid``, and most error also inherit from
            ``zope.schema.interfaces.ValidationError``. See below for a list of
            common exception types.
        request
            The current request. Use this to tie the error to a specific browser
            layer interface.
        widget
            The widget that was used. May be either a widget interface or a specific
            widget class.
        field
            The field that was used, normally given as a field instance obtained from
            an interface, as illustrated above.
        form
            The current form, either as a class or an interface. This is useful if
            the same interface is used in more than one form, but you only want the
            error to be shown in one form.
        content
            The content item that is acting as the context for the form. May be given
            as either an interface or a class.
        
        None of these parameters is required, but you would normally supply at least
        ``error``. In most cases, you should also supply the ``field``, as shown
        above.
        
        The most common validation error exception types are defined in
        ``zope.schema``, and can be imported from ``zope.schema.interfaces``:
        
        * ``RequiredMissing``, used when a required field is submitted without a value
        * ``WrongType``, used when a field is passed a value of an invalid type
        * ``TooBig`` and ``TooSmall``, used when a value is outside the ``min`` and/or
          ``max`` range specified for ordered fields (e.g. numeric or date fields)
        * ``TooLong`` and ``TooShort``, used when a value is outside the
          ``min_length`` and/or ``max_length`` range specified for length-aware fields
          (e.g. text or sequence fields)
        * ``InvalidValue``, used when a value is invalid, e.g. a non-ASCII character
          passed to an ASCII field
        * ``ConstraintNotSatisfied``, used when a ``constraint`` method returns
          ``False``
        * ``WrongContainedType``, used if an object of an invalid type is added
          to a sequence (i.e. the type does not conform to the field's
          ``value_type``)
        * ``NotUnique``, used if a uniqueness constraint is violated
        * ``InvalidURI``, used for ``URI`` fields if the value is not a valid URI
        * ``InvalidId``, used for ``Id`` fields if the value is not a valid id
        * ``InvalidDottedName``, used for ``DottedName`` fields if the value is not
          a valid dotted name
        
        Form base classes
        -----------------
        
        If you need to create your own forms, this package provides a number of
        convenient base classes that will be grokked much like a ``grok.View``.
        
        In Zope 2.10, the grokkers take care of wrapping the form in a
        `plone.z3cform`_ FormWrapper as well. In Zope 2.12 and later, there is no
        wrapper by default. If you want one (e.g. if you are using a custom template
        and you need it to work in both Zope 2.10 and 2.12), you can use the
        ``form.wrap()`` directive in the form class.
        
        The base classes can all be imported from ``plone.directives.form``, e.g::
        
            from five import grok
            from plone.directives import form, button
            from z3c.form import field
            
            class MyForm(form.Form):
                grok.context(ISomeContext)
                grok.require('zope2.View')
                
                fields = field.Fields(IMyFormSchema)
                
                @button.buttonAndHandler(u'Submit')
                def handleApply(self, action):
                    data, errors = self.extractData()
                    ...
        
        The allowed directives are:
        
        * ``grok.context()``, to specify the context of form view. If not given, the
          grokker will look for a module-level context, much like the standard
          ``grok.View``.
        * ``grok.require()``, to specify a permission. The default is ``zope2.View``
          for standard forms, ``cmf.ModifyPortalContent`` for edit forms, and
          ``cmf.AddPortalContent`` for add forms.
        * ``grok.layer()`` to specify a browser layer
        * ``grok.name()`` to set a different name. By default your form will be 
          available as view @@yourformclassnamelowercase, but you can use 
          ``grok.name()`` to set name explicitly.
        * ``form.wrap()`` to wrap the form in a layout wrapper view. You can pass
          an argument of ``True`` or ``False`` to enable or disable wrapping. If no
          argument is given, it defaults to ``True``. If omitted, the global default
          is used, which is to wrap in Zope 2.11 or earlier, and to not wrap in Zope
          2.12 or later
          
        More complex example how to use Grok directives with a form::
        
                from plone.directives import form
                from Products.CMFCore.interfaces import ISiteRoot
          
                class CompanyCreationForm(form.SchemaForm):
                    """ A sample form how to "create companies". 
                    
                    """
                              
                    # Which plone.directives.form.Schema subclass is used to define 
                    # fields for this form (not shown on this example)
                    schema = ICompanyCreationFormSchema
                    
                    # Permission required to view/submit the form
                    grok.require("cmf.ManagePortal")
                    
                    # The form does not care about the context object
                    # and  should not try to extract field value
                    # defaults out of it
                    ignoreContext = True
                    
                    # This form is available at the site root only
                    grok.context(ISiteRoot)
                
                    # The form will be available in Plone site root only
                    # Use http://yourhost/@@create_company URL to access this form
                    grok.name("create_company")
            
            
        
        
        Each of the form base classes has a "schema" equivalent, which can be
        initialised with a ``schema`` attribute instead of the ``fields`` attribute.
        These forms use `plone.autoform`_'s ``AutoExtensibleForm`` as a base class,
        allowing schema hints as shown above to be processed::
            
            from plone.directives import form
            from z3c.form import field
            
            class MyForm(form.SchemaForm):
                grok.context(ISomeContext)
                grok.require('zope2.View')
                
                schema = IMySchema
                
                @button.buttonAndHandler(u'Submit')
                def handleApply(self, action):
                    data, errors = self.extractData()
                    ...
        
        Note that the ``schema`` can be omitted if you are using ``SchemaForm`` or
        ``SchemaEditForm`` and you have given an interface as the argument to
        ``grok.context()``. In this case, the context interface will be used as the
        default schema.
        
        The available form base classes are:
        
        Form
            A simple page form, basically a grokked version of ``z3c.form.form.Form``.
        
        SchemaForm
            A page form that uses `plone.autoform`_. You must set the ``schema`` class
            variable (or implement it as a property) to a schema interface form which
            the form will be built. Form widget hints will be taken into account.
        
        AddForm
            A simple add form with "Add" and "Cancel" buttons. You must implement
            the ``create()`` and ``add()`` methods. See the `z3c.form`_ documentation
            for more details.
        
        SchemaAddForm
            An add form using `plone.autoform`_. Again, you must set the ``schema``
            class variable.
        
        EditForm
            A simple edit form with "Save" and "Cancel" buttons. See the `z3c.form`_
            documentation for more details.
        
        SchemaEditForm
            An edit form using `plone.autoform`_. Again, you must set the ``schema``
            class variable.
        
        DisplayForm
            A view with an automatically associated template (like ``grok.View``),
            that is initialised with display widgets. See `plone.autoform`_'s
            ``WidgetsView`` for more details.
        
        All of the grokked form base classes above support associating a custom 
        template with the form. This uses the same semantics as ``grok.View``. See
        `grokcore.view`_ for details, but briefly:
        
        * If you want to completely customise rendering, you can override the 
          ``render()`` method.
        * If you want to use a page template to render a form called ``MyForm`` in
          the module ``my.package.forms``, create a directory inside ``my.package``
          called ``forms_templates`` (the prefix should match the module name),
          and place a file there called ``myform.pt``.
        * If you do neither, the default form template will be used, as is the 
          standard behaviour in z3c.form.
        
        Note that the automatically associated form template can use ``grok.View``
        methods, such as ``view.url()`` and ``view.redirect()``, which are defined
        in the grokked form base classes.
        
        Also note that you can use the view ``@@ploneform-macros`` from 
        `plone.app.z3cform`_ if you want to use some of the standard form markup.
        For example, the ``titlelessform`` macro will render the ``<form >`` element
        and all fieldsets and fields::
        
            <metal:block use-macro="context/@@ploneform-macros/titlelessform" />
        
        Troubleshooting
        ---------------
        
        Forms are not found
        =====================
        
        When you try to access your form on the site, you'll get page not found (NotFound exception).
        
        * Make sure that you typed your form name correctly and it matches ``grok.name()``
          or lowercased class name
          
        * Make sure you have <include package="plone.directives.form" file="meta.zcml" />
          or similar in configure.zcml of your add-on product
        
        .. _five.grok: http://pypi.python.org/pypi/five.grok
        .. _z3c.form: http://pypi.python.org/pypi/z3c.form
        .. _plone.z3cform: http://pypi.python.org/pypi/plone.z3cform
        .. _plone.app.z3cform: http://pypi.python.org/pypi/plone.app.z3cform
        .. _plone.supermodel: http://pypi.python.org/pypi/plone.supermodel
        .. _plone.autoform: http://pypi.python.org/pypi/plone.autoform
        .. _grokcore.view: http://pypi.python.org/pypi/grokcore.view
        
        Changelog
        =========
        
        1.1 (2013-08-14)
        ----------------
        
        * Change i18n domain to plone.dexterity to reuse the translations. plone.dexterity
          already has all the strings needed.
          [gaudenz]
        
        * Fixes documentation mistake of documented ``form.wrapped()`` directive
          which is in fact ``form.wrap()``
          [romanofski]
        
        * A number of schema directives were moved to other packages and reimplemented 
          to not depend on grok.  The ``Schema`` class and the ``model``, ``fieldset``, 
          and ``primary`` directives were moved to ``plone.supermodel.model``. The 
          ``omitted``, ``no_omit``, ``mode``, ``widget``, ``order_before``, 
          ``order_after``, ``read_permission``, and ``write_permission`` directives were 
          moved to ``plone.autoform.directives``.
          
          For now the directives are still available under their old names in this
          package, but they are deprecated and may be removed at some point.
          
          Some minor related changes:
          
          * Tagged values are now stored on schemas as soon as they are defined, rather
            than when the schemas are grokked. Additional actions required by the
            directives, if any, are performed at the end of ZCML configuration.
          * Due to a bug in zope.interface, ``plone.supermodel.model.Schema`` must be
            the `first` base class of any schema to which the directives should apply.
            Also, unfortunately it is no longer possible to give an error if the schema
            directives are called on an interface that is not a ``Schema``.
          
          [davisagli]
        
        1.0 - 2011-05-20
        ----------------
        
        * No changes.
        
        1.0b7 - 2010-04-20
        ------------------
        
        * Allow arbitrary extra parameters for the fieldset directive. This is useful
          for extensions that want to tweak fieldset behaviour or rendering.
          [wichert]
          
        * Add ``no_omit`` directive, so that fields that have been omitted can be
          re-included again on for a more specific form interface.
          [davisagli]
        
        * Accept a form interface as an optional positional argument for the ``mode``
          and ``omitted`` directives, and store it in the tagged values using the new
          format expected by plone.autoform.
          [davisagli]
        
        * Add ``@form.error_message()`` decorator for registering custom error
          messages for errors and/or fields.
          [optilude]
        
        * Add ``@form.validator()`` decorator to register a simple field validator.
          See README.txt for details.
          [optilude]
        
        * Support unwrapped forms (in Zope 2.12). The default is to wrap in Zope <
          2.12, and not to wrap in Zope >= 2.12. A new ``form.wrapped()`` directive
          can be used to force wrapping or non-wrapping (by passing ``False`` as an
          argument).
          [optilude]
        
        * Warn more forcefully when using form directives on interfaces not deriving
          from ``Schema``, or using schema hints that refer to field names that cannot
          be found.
          [optilude]
        
        1.0b6 - 2009-10-08
        ------------------
        
        * Add support for the ``primary()`` directive, which is used to set the
          primary field for marshalling. See the ``plone.rfc822`` for details.
          [optilude]
        
        1.0b5 - 2009-07-21
        ------------------
        
        * Updated to new five.grok release.
          [optilude]
        
        1.0b3 - 2009-07-12
        ------------------
        
        * Made adjustments for changes in plone.supermodel's API.
          [optilude]
        
        1.0b2 - 2009-06-15
        ------------------
        
        * Make sure that we don't lose the function when using the
          @form.default_value() decorator and the other value decorators.
          [optilude]
        
        1.0b1 - 2009-04-17
        ------------------
        
        * Initial release
        
        
Keywords: grok plone dexterity form content
Platform: UNKNOWN
Classifier: Framework :: Plone
Classifier: Programming Language :: Python
Classifier: Topic :: Software Development :: Libraries :: Python Modules
