Authomatic
is an authorization / authentication
client library for Python web applications
inspired by Alex Vagin’s Simpleauth.
In fact, I almost named it Deadsimpleauth,
but that name would be too long
for a succinct library.

- Tweet

# Source code for authomatic.providers.openid

    # -*- coding: utf-8 -*-
    """
    |openid| Providers
    ----------------------------------

    Providers which implement the |openid|_ protocol based on the
    `python-openid`_ library.

    .. warning::

        This providers are dependent on the |pyopenid|_ package.

    .. autosummary::

        OpenID
        Yahoo
        Google

    """

    # We need absolute import to import from openid library which has the same name as this module
    from __future__ import absolute_import
    import datetime
    import logging
    import time

    from openid import oidutil
    from openid.consumer import consumer
    from openid.extensions import ax, pape, sreg
    from openid.association import Association

    from authomatic import providers
    from authomatic.exceptions import FailureError, CancellationError, OpenIDError

    __all__ = ['OpenID', 'Yahoo', 'Google']

    # Suppress openid logging.
    oidutil.log = lambda message, level=0: None

    REALM_HTML = \
    """
    <!DOCTYPE html>
    <html>
        <head>
            <meta http-equiv="X-XRDS-Location" content="{xrds_location}" />
        </head>
        <body>{body}</body>
    </html>
    """

    XRDS_XML = \
    """
    <?xml version="1.0" encoding="UTF-8"?>
    <xrds:XRDS
        xmlns:xrds="xri://$xrds"
        xmlns:openid="http://openid.net/xmlns/1.0"
        xmlns="xri://$xrd*($v*2.0)">
        <XRD>
            <Service priority="1">
                <Type>http://specs.openid.net/auth/2.0/return_to</Type>
                <URI>{return_to}</URI>
            </Service>
        </XRD>
    </xrds:XRDS>
    """

    class SessionOpenIDStore(object):
        """
        A very primitive session-based implementation of the :class:`openid.store.interface.OpenIDStore`
        interface of the `python-openid`_ library.

        .. warning::

            Nonces get verified only by their timeout. Use on your own risk!

        """

        _log = lambda level, message: None

        def __init__(self, session, nonce_timeout=None):
            """
            :param int nonce_timeout:
                Nonces older than this in seconds will be considered expired.
                Default is 600.
            """

            self.session = session
            self.nonce_timeout = nonce_timeout or 600

        def storeAssociation(self, server_url, association):
            self._log(logging.DEBUG, 'SessionOpenIDStore: Storing association to session.')
            # Always store only one association as a tuple.
            self.session['oia'] = (server_url, association.handle, association.serialize())

        def getAssociation(self, server_url, handle=None):
            # Try to get association.
            assoc = self.session.get('oia')

            if assoc and assoc[0] == server_url:
                # If found deserialize and return it.
                self._log(logging.DEBUG, 'SessionOpenIDStore: Association found.')
                return Association.deserialize(assoc[2])
            else:
                self._log(logging.DEBUG, 'SessionOpenIDStore: Association not found.')

        def removeAssociation(self, server_url, handle):
            # Just inform the caller that it's gone.
            True

        def useNonce(self, server_url, timestamp, salt):
            # Evaluate expired nonces as false.
            age = int(time.time()) - int(timestamp)
            if age < self.nonce_timeout:
                return True
            else:
                self._log(logging.ERROR, 'SessionOpenIDStore: Expired nonce!')
                return False

    class OpenID(providers.AuthenticationProvider):
        """
        |openid|_ provider based on the `python-openid`_ library.
        """

        AX = ['http://axschema.org/contact/email',
              'http://schema.openid.net/contact/email',
              'http://axschema.org/namePerson',
              'http://openid.net/schema/namePerson/first',
              'http://openid.net/schema/namePerson/last',
              'http://openid.net/schema/gender',
              'http://openid.net/schema/language/pref',
              'http://openid.net/schema/contact/web/default',
              'http://openid.net/schema/media/image',
              'http://openid.net/schema/timezone']

        AX_REQUIRED = ['http://schema.openid.net/contact/email']

        SREG = ['nickname',
                'email',
                'fullname',
                'dob',
                'gender',
                'postcode',
                'country',
                'language',
                'timezone']

        PAPE = ['http://schemas.openid.net/pape/policies/2007/06/multi-factor-physical',
                'http://schemas.openid.net/pape/policies/2007/06/multi-factor',
                'http://schemas.openid.net/pape/policies/2007/06/phishing-resistant']

        def __init__(self, *args, **kwargs):
            """
            Accepts additional keyword arguments:

            :param store:
                Any object which implements :class:`openid.store.interface.OpenIDStore`
                of the `python-openid`_ library.

            :param bool use_realm:
                Whether to use `OpenID realm <http://openid.net/specs/openid-authentication-2_0-12.html#realms>`_.
                If ``True`` the realm HTML document will be accessible at
                ``{current url}?{realm_param}={realm_param}``
                e.g. ``http://example.com/path?realm=realm``.

            :param str realm_body:
                Contents of the HTML body tag of the realm.

            :param str realm_param:
                Name of the query parameter to be used to serve the realm.

            :param str xrds_param:
                The name of the query parameter to be used to serve the
                `XRDS document <http://openid.net/specs/openid-authentication-2_0-12.html#XRDS_Sample>`_.

            :param list sreg:
                List of strings of optional
                `SREG <http://openid.net/specs/openid-simple-registration-extension-1_0.html>`_ fields.
                Default = :attr:`OpenID.SREG`.

            :param list sreg_required:
                List of strings of required
                `SREG <http://openid.net/specs/openid-simple-registration-extension-1_0.html>`_ fields.
                Default = ``[]``.

            :param list ax:
                List of strings of optional
                `AX <http://openid.net/specs/openid-attribute-exchange-1_0.html>`_ schemas.
                Default = :attr:`OpenID.AX`.

            :param list ax_required:
                List of strings of required
                `AX <http://openid.net/specs/openid-attribute-exchange-1_0.html>`_ schemas.
                Default = :attr:`OpenID.AX_REQUIRED`.

            :param list pape:
                of requested
                `PAPE <http://openid.net/specs/openid-provider-authentication-policy-extension-1_0.html>`_
                policies.
                Default = :attr:`OpenID.PAPE`.

            As well as those inherited from :class:`.AuthenticationProvider` constructor.
            """

            super(OpenID, self).__init__(*args, **kwargs)

            # Allow for other openid store implementations.
            self.store = self._kwarg(kwargs, 'store', SessionOpenIDStore(self.session))

            # Realm
            self.use_realm = self._kwarg(kwargs, 'use_realm', True)
            self.realm_body = self._kwarg(kwargs, 'realm_body', '')
            self.realm_param = self._kwarg(kwargs, 'realm_param', 'realm')
            self.xrds_param = self._kwarg(kwargs, 'xrds_param', 'xrds')

            #SREG
            self.sreg = self._kwarg(kwargs, 'sreg', self.SREG)
            self.sreg_required = self._kwarg(kwargs, 'sreg_required', [])

            # AX
            self.ax = self._kwarg(kwargs, 'ax', self.AX)
            self.ax_required = self._kwarg(kwargs, 'ax_required', self.AX_REQUIRED)
            # add required schemas to schemas if not already there
            for i in self.ax_required:
                if i not in self.ax:
                    self.ax.append(i)

            # PAPE
            self.pape = self._kwarg(kwargs, 'pape', self.PAPE)

        @staticmethod
        def _x_user_parser(user, data):

            user.first_name = data.get('ax', {}).get('http://openid.net/schema/namePerson/first')
            user.last_name = data.get('ax', {}).get('http://openid.net/schema/namePerson/last')
            user.id = data.get('guid')
            user.link = data.get('ax', {}).get('http://openid.net/schema/contact/web/default')
            user.picture = data.get('ax', {}).get('http://openid.net/schema/media/image')
            user.nickname = data.get('sreg', {}).get('nickname')
            user.country = data.get('sreg', {}).get('country')
            user.postal_code = data.get('sreg', {}).get('postcode')

            user.name = data.get('sreg', {}).get('fullname') or \
                data.get('ax', {}).get('http://axschema.org/namePerson')

            user.gender = data.get('sreg', {}).get('gender') or \
                data.get('ax', {}).get('http://openid.net/schema/gender')

            user.locale = data.get('sreg', {}).get('language') or \
                data.get('ax', {}).get('http://openid.net/schema/language/pref')

            user.timezone = data.get('sreg', {}).get('timezone') or \
                data.get('ax', {}).get('http://openid.net/schema/timezone')

            user.email = data.get('sreg', {}).get('email') or \
                data.get('ax', {}).get('http://axschema.org/contact/email') or \
                data.get('ax', {}).get('http://schema.openid.net/contact/email')

            user.birth_date = datetime.datetime.strptime(data.get('sreg', {}).get('dob'), '%Y-%m-%d') if \
                data.get('sreg', {}).get('dob') else None

            return user

        @providers.login_decorator
        def login(self):

            # Instantiate consumer
            self.store._log = self._log
            oi_consumer = consumer.Consumer(self.session, self.store)

            # handle realm and XRDS if there is only one query parameter
            if self.use_realm and len(self.params) == 1:
                realm_request = self.params.get(self.realm_param)
                xrds_request = self.params.get(self.xrds_param)
            else:
                realm_request = None
                xrds_request = None

            # determine type of request
            if realm_request:
                #===================================================================
                # Realm HTML
                #===================================================================

                self._log(logging.INFO, 'Writing OpenID realm HTML to the response.')
                xrds_location = '{u}?{x}={x}'.format(u=self.url, x=self.xrds_param)
                self.write(REALM_HTML.format(xrds_location=xrds_location, body=self.realm_body))

            elif xrds_request:
                #===================================================================
                # XRDS XML
                #===================================================================

                self._log(logging.INFO, 'Writing XRDS XML document to the response.')
                self.set_header('Content-Type', 'application/xrds+xml')
                self.write(XRDS_XML.format(return_to=self.url))

            elif self.params.get('openid.mode'):
                #===================================================================
                # Phase 2 after redirect
                #===================================================================

                self._log(logging.INFO, 'Continuing OpenID authentication procedure after redirect.')

                # complete the authentication process
                response = oi_consumer.complete(self.params, self.url)

                # on success
                if response.status == consumer.SUCCESS:

                    data = {}

                    # get user ID
                    data['guid'] = response.getDisplayIdentifier()

                    self._log(logging.INFO, 'Authentication successful.')

                    # get user data from AX response
                    ax_response = ax.FetchResponse.fromSuccessResponse(response)
                    if ax_response and ax_response.data:
                        self._log(logging.INFO, 'Got AX data.')
                        ax_data = {}
                        # convert iterable values to their first item
                        for k, v in ax_response.data.iteritems():
                            if v and type(v) in (list, tuple):
                                ax_data[k] = v[0]
                        data['ax'] = ax_data

                    # get user data from SREG response
                    sreg_response = sreg.SRegResponse.fromSuccessResponse(response)
                    if sreg_response and sreg_response.data:
                        self._log(logging.INFO, 'Got SREG data.')
                        data['sreg'] = sreg_response.data

                    # get data from PAPE response
                    pape_response = pape.Response.fromSuccessResponse(response)
                    if pape_response and pape_response.auth_policies:
                        self._log(logging.INFO, 'Got PAPE data.')
                        data['pape'] = pape_response.auth_policies

                    # create user
                    self._update_or_create_user(data)

                    #===============================================================
                    # We're done!
                    #===============================================================

                elif response.status == consumer.CANCEL:
                    raise CancellationError('User cancelled the verification of ID "{}"!'.format(response.getDisplayIdentifier()))

                elif response.status == consumer.FAILURE:
                    raise FailureError(response.message)

            elif self.params.get(self.identifier_param):
                #===================================================================
                # Phase 1 before redirect
                #===================================================================

                self._log(logging.INFO, 'Starting OpenID authentication procedure.')

                # get AuthRequest object
                try:
                    auth_request = oi_consumer.begin(self.identifier)
                except consumer.DiscoveryFailure as e:
                    raise FailureError('Discovery failed for identifier {}!'.format(self.identifier),
                                       url=self.identifier,
                                       original_message=e.message)

                self._log(logging.INFO, 'Service discovery for identifier {} successful.'.format(self.identifier))

                # add SREG extension
                # we need to remove required fields from optional fields because addExtension then raises an error
                self.sreg = [i for i in self.sreg if i not in self.sreg_required]
                auth_request.addExtension(sreg.SRegRequest(optional=self.sreg,
                                                           required=self.sreg_required))

                # add AX extension
                ax_request = ax.FetchRequest()
                # set AX schemas
                for i in self.ax:
                    required = i in self.ax_required
                    ax_request.add(ax.AttrInfo(i, required=required))
                auth_request.addExtension(ax_request)

                # add PAPE extension
                auth_request.addExtension(pape.Request(self.pape))

                # prepare realm and return_to URLs
                if self.use_realm:
                    realm = return_to = '{u}?{r}={r}'.format(u=self.url, r=self.realm_param)
                else:
                    realm = return_to = self.url

                url = auth_request.redirectURL(realm, return_to)

                if auth_request.shouldSendRedirect():
                    # can be redirected
                    url = auth_request.redirectURL(realm, return_to)
                    self._log(logging.INFO, 'Redirecting user to {}.'.format(url))
                    self.redirect(url)
                else:
                    # must be sent as POST
                    # this writes a html post form with auto-submit
                    self._log(logging.INFO, 'Writing an auto-submit HTML form to the response.')
                    form = auth_request.htmlMarkup(realm, return_to, False, dict(id='openid_form'))
                    self.write(form)
            else:
                raise OpenIDError('No identifier specified!')

    class Yahoo(OpenID):
        """
        Yahoo  :class:`.OpenID` provider with the :attr:`.identifier` predefined to ``"me.yahoo.com"``.
        """

        identifier = 'me.yahoo.com'

    class Google(OpenID):
        """
        Google :class:`.OpenID` provider with the :attr:`.identifier` predefined to ``"https://www.google.com/accounts/o8/id"``.
        """

        identifier = 'https://www.google.com/accounts/o8/id'