=========
 Schemas
=========

This package is heavily driven by :term:`schemas <schema>`. The schema
determines what attributes of an :term:`internal object` are
externalized based on its fields, and how incoming data in an external object are
internalized, including all sorts of validation options.

Here is an example of some schemas.

.. code-block:: python

    from zope.interface import Interface
    from zope.interface import taggedValue

    from zope.schema import List
    from zope.schema import Object
    from zope.schema import URI

    from nti.schema.field import Dict
    from nti.schema.field import TextLine
    from nti.schema.field import ValidTextLine
    from nti.schema.field import DecodingValidTextLine

    class IRootInterface(Interface):
        pass

    class IFriendlyNamed(Interface):

        alias = TextLine(title=u'Display alias',
                         description=u"Enter preferred display name alias, e.g., johnnyboy."
                         u"Your site may impose limitations on this value.",
                         required=False)

        realname = TextLine(title=u'Full Name aka realname',
                            description=u"Enter full name, e.g. John Smith.",
                            required=False,
                            constraint=checkRealname)

    class IAvatarURL(Interface):
        """
        Something that features a display URL.
        """

        avatarURL = URI(title=u"URL of your avatar picture",
                        description=u"If not provided, one will be generated for you.",
                        required=False)


    class IBackgroundURL(Interface):

        backgroundURL = URI(title=u"URL of your background picture",
                            description=u"If not provided, one will be generated for you.",
                            required=False)


    class IProfileAvatarURL(IAvatarURL, IBackgroundURL):
        pass


    class IAddress(IRootInterface):

        full_name = ValidTextLine(title=u"First name", required=True)

        street_address_1 = ValidTextLine(title=u"Street line 1",
                                         max_length=75, required=True)

        street_address_2 = ValidTextLine(title=u"Street line 2",
                                         required=False, max_length=75)

        city = ValidTextLine(title=u"City name", required=True)

        state = ValidTextLine(title=u"State name",
                              required=False, max_length=10)

        postal_code = ValidTextLine(title=u"Postal code",
                                    required=False, max_length=30)

        country = ValidTextLine(title=u"Nation name", required=True)
        taggedValue('__external_class_name__',
                    'Address')


    class IUserContactProfile(Interface):

        addresses = Dict(title=u"A mapping of address objects.",
                         key_type=DecodingValidTextLine(title=u"Adresss key"),
                         value_type=Object(IAddress),
                         min_length=0,
                         required=False)

        phones = Dict(title=u"A mapping of phone numbers objects.",
                      key_type=ValidTextLine(title=u"Phone key"),
                      value_type=ValidTextLine(title=u"A phone"),
                      min_length=0,
                      required=False)

        contact_emails = Dict(title=u"A mapping of contact emails.",
                              key_type=DecodingValidTextLine(title=u"Email key"),
                              value_type=ValidTextLine(title=u'Email',
                                                       constraint=checkEmailAddress),
                              min_length=0,
                              required=False)

    class IUserProfile(IProfileAvatarURL,
                       IUserContactProfile,
                       IFriendlyNamed,
                       IRootInterface):
        """A user profile"""
        taggedValue('__external_class_name__',
                    'UserProfile')