Metadata-Version: 1.1
Name: repoze.formapi
Version: 0.6.1
Summary: Minimalistic form library.
Home-page: UNKNOWN
Author: Malthe Borch
Author-email: repoze-dev@lists.repoze.org
License: BSD-derived (http://www.repoze.org/LICENSE.txt)
Description: The ``repoze.formapi`` provides a form library which integrates with
        HTML forms instead of abstracting them away.
        
        It provides a small framework to take you through the entire process
        of rendering a form, provide default values, validate and execute form
        actions.
        
        Form fields are defined using Python base types which map out nested
        data structures with end points that are either integers, strings,
        floats or tuples of these. It's up to the application to bridge these
        with more complex objects.
        
        
        Introduction
        ============
        
        This library helps you parse, validate and deserialize form input as
        well as execute form actions.
        
        The starting point is to define the data structure that describes your
        data. For instance, an action string and a list of numbers (typical
        for a form that allows a user to select some items and apply an
        action):
        
        >>> fields = {
        ...     'action': unicode,
        ...     'items': [int]
        ... }
        
        Let's apply the following input sequence:
        
        >>> params = [
        ...      ('action', 'submit'),
        ...      ('items', 1),
        ...      ('items', 2),
        ...      ('security-token', '...')
        ... ]
        
        Note that ``'security-token'`` is an example of a parameter that is
        provided, but not defined in the fields. That's not an error.
        
        Now, to parse the parameters above into the data structure defined by
        our fields definition, we use the ``parse`` function (note that in the
        rest of this text, we assume that symbols have been imported).
        
        >>> from repoze.formapi import parse
        >>> data, errors = parse(params, fields)
        
        In the logic that handles this call, you'll typically want to test if
        the ``errors`` value is true (meaning there was an error) or false
        (meaning there was no error).
        
        >>> bool(errors)
        False
        
        Let's take a look at the data:
        
        >>> data
        {'action': u'submit', 'items': [1, 2]}
        
        
        Types
        =====
        
        In the previous example, we used Python's built-in data types: ``int``
        and ``unicode``.
        
        However, you can use any callable as the data type. Note that if the
        callable raises a ``KeyError``, then it's simply ignored.
        
        Let's try an example:
        
        >>> data, errors = parse((('foo', 'bar'), ('baz', 'boo'), ('baz', 'qux')), {
        ...     'foo': str.upper,
        ...     'baz': {'boo': 'yes'}.__getitem__,
        ... })
        
        What can we expect in ``data``?
        
        The ``'foo'`` parameter will be uppercased, the first ``'baz'``
        resolves to ``'yes'``, while the other raises a ``KeyError`` and is
        ignored.
        
        >>> data
        {'foo': 'BAR', 'baz': 'yes'}
        
        It's useful to remember that if you want a parameter to be ignored,
        simply raise a ``KeyError``.
        
        
        Forms
        =====
        
        The library provides an abstraction for handling forms.
        
        To create a form you subclass the ``Form`` class and define the form
        field definitions in the ``fields`` attribute.
        
        >>> class TapeForm(Form):
        ...     """Casette tape form."""
        ...
        ...     fields = {
        ...         'artist': unicode,
        ...         'title': unicode,
        ...         'asin': str,
        ...         'year': int,
        ...         'playtime': float
        ...     }
        
        If there are no start or *default* values, the form can be
        instantiated with no arguments:
        
        >>> form = TapeForm()
        
        The form data is available from the ``data`` attribute. Since we
        didn't pass in a request, there's no data available.
        
        >>> form.data['artist'] is None
        True
        
        That's not very interesting. Let's pass an input parameter.
        
        >>> params = (('title', u'Motorcity Detroit USA Live'),)
        >>> form = TapeForm(params=params)
        
        This will set the ``'title'`` field.
        
        The input is a valid unicode string and there are no validation
        errors.
        
        >>> form.validate()
        True
        
        Let's confirm that the data is available.
        
        >>> form.data['title']
        u'Motorcity Detroit USA Live'
        
        The library also support passing in a ``request`` argument, if this is
        an object that has a ``params`` attribute.
        
        >>> request = Request(params=params)
        
        The ``Request`` class from `WebOb <http://pypi.python.org/pypi/WebOb>`_
        (a popular package that provides an object-oriented interface to the
        HTTP protocol) is compatible.
        
        >>> form = TapeForm(request=request)
        
        We'll often want to initialize the form with default values. To this
        effect we pass in a dictionary object.
        
        >>> data = {
        ...    'artist': u'Bachman-Turner Overdrive',
        ...    'title': u'Four Wheel Drive',
        ...    'asin': 'B000001FL8',
        ...    'year': 1975,
        ...    'playtime': 33.53
        ... }
        >>> form = TapeForm(data)
        
        The values are available in the form data object.
        
        >>> form.data['title']
        u'Four Wheel Drive'
        
        However, if we pass in the request from the former example, we'll see
        that values from the request are used before the passed dictionary
        object is queried.
        
        >>> form = TapeForm(data, request=request)
        >>> form.data['title']
        u'Motorcity Detroit USA Live'
        
        The provided ``data`` dictionary is unchanged at this point:
        
        >>> data['title']
        u'Four Wheel Drive'
        
        We need to invoke the ``save`` method to commit the changes to the
        provided dictionary.
        
        >>> form.data.save()
        >>> data['title']
        u'Motorcity Detroit USA Live'
        
        
        Additional validation
        ---------------------
        
        It is possible to create validation methods for more complex
        needs. These extra validators can be hooked up using the `validator`
        decorator.
        
        >>> class CDForm(Form):
        ...     fields = {
        ...         'artist': unicode,
        ...         'title': unicode,
        ...         'asin': str,
        ...         'year': int,
        ...         'genre': str,
        ...         'playtime': float}
        ...
        ...     @validator
        ...     def check_genre(self):
        ...         if self.data['genre'] != 'rock':
        ...             yield 'Genre is invalid'
        
        A validator can look at all the data that is available. This makes it
        easy to create validators that need to check multiple fields.
        
        >>> form = CDForm()
        >>> form.validate()
        False
        
        The errors attribute contains our error message.
        
        >>> form.errors[0]
        'Genre is invalid'
        
        Errors can also be assigned to a specific field. To do this a
        validator can register itself for a specific field.
        
        >>> class CDForm(Form):
        ...
        ...     fields = {
        ...         'artist': unicode,
        ...         'title': unicode,
        ...         'asin': str,
        ...         'year': int,
        ...         'genre': str,
        ...         'playtime': float}
        ...
        ...     @validator('genre')
        ...     def check_genre(self):
        ...         if self.data['genre'] != 'rock':
        ...             yield 'Genre is invalid'
        
        When this form is validated it will have the error available for the
        specific field.
        
        >>> form = CDForm()
        >>> form.validate()
        False
        >>> 'genre' in form.errors
        True
        >>> form.errors['genre'][0]
        'Genre is invalid'
        
        Form context
        ------------
        
        We can set the context of a form to some object.
        
        >>> class Tape:
        ...    title = u'Motorcity Detroit USA Live'
        ...    asin = 'B000001FL8'
        ...    year = 1975
        
        >>> tape = Tape()
        
        The form data will draw defaults from the context.
        
        >>> form = TapeForm(context=tape)
        >>> form.data['title']
        u'Motorcity Detroit USA Live'
        
        Request parameters take priority over the context. In the following
        example, we submit the form with trivial input.
        
        >>> request = Request(params=(('asin', u''), ('year', u'')))
        >>> form = TapeForm(context=tape, request=request)
        
        This form input is valid; although ``year`` is an integer field, the
        trivial input is valid and will be assigned a value of ``None``.
        
        >>> form.validate()
        True
        
        The ``asin`` input is coerced to a string (from unicode).
        
        >>> form.data['asin']
        ''
        
        The ``year`` input is trivial. It's not a required field, so the value
        is ``None`` (treated as a non-input).
        
        >>> form.data['year'] is None
        True
        
        Required fields
        ---------------
        
        We use the ``required`` method to mark fields required.
        
        Let's continue the example from above. If we make the fields required,
        the input no longer validates.
        
        >>> TapeForm.fields['year'] = required(int, u"Required field" )
        >>> TapeForm.fields['asin'] = required(str)
        
        The form input is no longer valid.
        
        >>> form = TapeForm(context=tape, request=request)
        >>> form.validate()
        False
        >>> form.data['year'] is None
        True
        
        The error message is available as well:
        
        >>> form.errors['year'][0]
        'Required field'
        
        Now let's try a valid input:
        
        >>> request = Request(params=(('asin', u'B000001FL8'), ('year', u'1978')))
        >>> form = TapeForm(context=tape, request=request)
        
        We can expect both required fields to be
        converted and correctly typed.
        
        >>> form.validate()
        True
        
        >>> form.data['asin']
        'B000001FL8'
        
        >>> form.data['year']
        1978
        
        Form submission
        ---------------
        
        If a form prefix has not been set, the request is applied by
        default. However, most applications will want to set a form prefix and
        require explicit form submission.
        
        A form submits a "default action" if the prefix is submitted as a
        parameter.
        
        >>> request = Request(params=(
        ...    ('tape_form', ''),
        ...    ('title', u'Motorcity Detroit USA Live')))
        >>> form = TapeForm(request=request, prefix='tape_form')
        >>> form.data['title']
        u'Motorcity Detroit USA Live'
        
        As expected, if we submit a form with a different prefix, the request
        is not applied.
        
        >>> form = TapeForm(request=request, prefix='other_form')
        >>> form.data['title'] is None
        True
        
        We can also define form actions on the form class itself.
        
        >>> class TapeAddForm(TapeForm):
        ...     """An add-form for a casette tape."""
        ...
        ...     @action
        ...     def handle_add(self, data):
        ...         print "add"
        ...
        ...     @action("add_and_edit")
        ...     def handle_add_and_edit(self, data):
        ...         print "add_and_edit"
        
        The first action is a "default action"; if we submit the request we
        set up before, this action will be read to be submitted.
        
        >>> form = TapeAddForm(request=request, prefix='tape_form')
        >>> form.actions
        [<Action name="" submitted="True">,
         <Action name="add_and_edit" submitted="False">]
        
        The submitted action is available in the ``action`` parameter.
        
        >>> form.action
        <Action name="" submitted="True">
        
        To call the form handler of the submitted action, we invoke the form's
        call method.
        
        >>> form()
        add
        
        To call the named form action, there must be a parameter in the
        request which is a concatenation of the prefix and the form action
        name. Accepted separation characters are '.' (dot), '_' (underscore)
        and '-' (dash).
        
        >>> request = Request(params=(
        ...    ('tape_form-add_and_edit', ''),
        ...    ('title', u'Motorcity Detroit USA Live'),))
        >>> form = TapeAddForm(request=request, prefix='tape_form')
        >>> form.actions
        [<Action name="" submitted="False">,
         <Action name="add_and_edit" submitted="True">]
        >>> form()
        add_and_edit
        
        Data proxies
        ------------
        
        We can bind a context object to a data object by using a proxy
        object. This technique can be used to create edit or add-forms.
        
        To illustrate this, let's define a content object. We'll hardcode
        default values for simplicity.
        
        >>> class Tape(object):
        ...    artist = u'Bachman-Turner Overdrive'
        ...    title = u'Four Wheel Drive'
        ...    asin = 'B000001FL8'
        ...    year = 1975
        ...    playtime = 33.53
        
        We can now create a data proxy for an instance of this class.
        
        >>> tape = Tape()
        >>> proxy = Proxy(tape)
        
        With no further intervention, this data object acts as a proxy to read
        and write attributes on the content object.
        
        >>> proxy.title
        u'Four Wheel Drive'
        >>> proxy.title = u'Motorcity Detroit USA Live'
        >>> tape.title
        u'Motorcity Detroit USA Live'
        
        If we want to have more control over this process, we can subclass and
        define descriptors.
        
        The following example defines custom behavior for the ``title``
        attribute; the value is uppercased.
        
        >>> class TapeProxy(Proxy):
        ...     def get_title(self):
        ...         return self.title
        ...
        ...     def set_title(self, value):
        ...         self.title = value.upper()
        ...
        ...     title = property(get_title, set_title)
        >>> proxy = TapeProxy(tape)
        
        If we read and write to the ``title`` attribute of this proxy object,
        the custom getter and setter functions are used.
        
        >>> proxy.title = u'Motorcity Detroit USA Live'
        
        As would be expected from a proxy, changes are actually made to the
        underlying content object.
        
        >>> tape.title
        u'MOTORCITY DETROIT USA LIVE'
        
        Saving form data
        ----------------
        
        When instantiating a form, you can pass in a proxy object instead of
        ``data``. This binds the data object to the proxy, but it also allows
        us to save the form data on the proxied object.
        
        >>> form = TapeForm(proxy, request=request)
        >>> form.data['title'] = u'Four Wheel Drive'
        
        Assignment behaves logically.
        
        >>> form.data['title']
        u'Four Wheel Drive'
        
        However, if we invoke the ``save`` action, changes take effect on the
        proxied object.
        
        >>> form.data.save()
        >>> tape.title
        u'FOUR WHEEL DRIVE'
        
        Changelog
        =========
        
        0.6.1 (2012-12-10)
        ------------------
        
        - Added support for the field definition callable to raise a
          ``KeyError`` exception such that the input is ignored.
        
        0.6 (2012-12-10)
        ----------------
        
        - The ``marshalling`` module has been renamed to ``parser``.
        
        - Fixed issue where an integer would cause an error even when not
          required.
        
        0.5.4 (2012-12-04)
        ------------------
        
        - Added ``keys`` method to marshaller such that the object can be used
          as a mapping.
        
        0.5.3 (2012-11-23)
        ------------------
        
        - Fixed an issue where a fields definition with a single entry would
          get incorrectly marshalled when the corresponding data had multiple
          entries.
        
        0.5.2 (2012-11-19)
        ------------------
        
        - Fixed an issue with `required` where the marshaller would not
          correctly convert a value to the provided value type.
        
        
        0.5.1 (2012-11-16)
        ------------------
        
        - Type-checking has been removed from the marshalling code::
        
            if not error and not isinstance(value, data_type):
                error = True
        
          This change was required to support "schema types" such as::
        
            import re
        
            match_email = re.compile(
                r"^(\w&.%#$&'\*+-/=?^_`{}|~]+!)*[\w&.%#$&'"
                r"\*+-/=?^_`{}|~]+@(([0-9a-z]([0-9a-z-]*[0-9a-z])"
                r"?\.)+[a-z]{2,6}|([0-9]{1,3}\.){3}[0-9]{1,3})$",
                re.IGNORECASE).match
        
            class email(unicode):
                def __new__(cls, string):
                  if match_email(string):
                      return string
        
                  raise ValueError(u"Not a valid e-mail address.")
        
        
        0.5.0 (2010-05-28)
        ------------------
        
        - Fixed ``Errors`` class to use the more obtuse ``__getattr__``
          override; this fixes an issue where an attribute lookup of
          ``__class__`` would fail. [malthe]
        
        - Added ``required`` decorator for field types; when we wrap a type
          with this decorator, inputs that do not validate (even the trivial
          input of the empty string) are given the input value as-is. Compare
          this to an optional field (the default setting) where the empty
          string will be interpreted as a non-input (unless it's a string type
          or another type which will accept the empty string). [malthe]
        
        - Add __contains__/has_key support to the Error class. [wichert]
        
        0.4.2 (2009-09-14)
        ------------------
        
        - Added ``any`` builtin fallback. [malthe]
        
        0.4.1 (2009-07-31)
        ------------------
        
        - Added defaultdict emulation class. [malthe]
        
        0.4 (2009-07-29)
        ----------------
        
        - The selected action, if any, is available in the ``action``
          attribute of a form instance. [malthe]
        
        - Even if form input does not validate, the input is available as-is
          in the ``data`` dictionary. [malthe, rnix]
        
        - Request parameters can now be provided directly as the ``params``
          keyword argument. [malthe]
        
        - Added ``get`` method to errors dictionary. [malthe]
        
        - Errors can now be compared with each other to see if they are the
          same. This makes it easier to test without doctest.
        
        - Made the truth test for the errors object check just for messages in
          itself or it's sub errors. This avoids having the errors object
          saying it is true after accessing a key for which no error exists
          (thus creating a new errors object). [jvloothuis]
        
        - Changed the base class of errors from unicode to object. This makes
          it behave like one would expect when printing etc. [jvloothuis]
        
        0.3.2 (2009-03-09)
        ------------------
        
        - Shedding unused dependency on 'zope.interface' [jvloothuis]
        
        0.3.1 (2008-10-27)
        ------------------
        
        - Make it possible to set `prefix` as class attribute. [malthe]
        
        - Fixed issue where action parameters would not get set. [malthe]
        
        0.3 (2008-10-27)
        ----------------
        
        - Marshalled data is no longer applied when no parameters are
          available from the request. [malthe]
        
        - Made the `errors`-object subclass unicode instead of defaultdict and
          implemented custom string representation function which concatenates
          error messages. [malthe]
        
        0.2 (2008-10-19)
        ----------------
        
        - Created/improved the abilities for custom validation. [jvloothuis]
        
        - Added form action support. [malthe]
        
        - Reworked marshalling code to handle dynamic dictionary
          keys. [malthe]
        
        - Implemented form data object which facilities the form processing
          flow from applying the request to committing changes to a context
          object. [malthe]
        
        - Integrated the converter into the ``form`` module. [seletz]
        
        - Added ``ValidationErrors`` object, which evaluates to True if validation
          errors occured. [seletz]
        
        - Added ``unicode`` converter. [seletz]
        
        - Added ``converter`` module to support converting and validating request
          parameters sent by a form. [seletz]
        
        - Added logic to allow registering and acquiring template API
          components from templates. [malthe]
        
        - Changed the Skin Template View to be a class, and added a minimal
          interface ISkinTemplate to access the template path [seletz]
        
        - Fixed a bug where we did not tear down the tests correctly [seletz]
        
        - Fixed bug where the INewRequest event handler would call
          templates when checking for their existence [seletz]
        
        0.1 (2008-09-25)
        ----------------
        
        - Initial release [malthe]
        
        - Added support to dynamically register templates if they
          are added to a registered template directory [seletz]
        
        
Keywords: forms html validation marshalling
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Environment :: Web Environment
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Zope Public License
Classifier: Programming Language :: Python
Classifier: Natural Language :: English
Classifier: Operating System :: OS Independent
Classifier: Topic :: Internet :: WWW/HTTP
