Python django.utils() Examples

def test_json_attributes(self):
        """test the json storage of ``atrributs`` in ``_attributs``"""
        # ge an authenticated client
        client = get_auth_client()
        # get the user associated to the client
        user = self.get_user(client)
        ticket = models.ServiceTicket.objects.create(
            user=user,
            service=self.service,
            attributs=settings.CAS_TEST_ATTRIBUTES,
            service_pattern=self.service_pattern
        )
        self.assertEqual(utils.json_encode(settings.CAS_TEST_ATTRIBUTES), ticket._attributs)
        ticket.delete()
        ticket = models.ServiceTicket.objects.create(
            user=user,
            service=self.service,
            service_pattern=self.service_pattern
        )
        self.assertIsNone(ticket._attributs)
        self.assertIsNone(ticket.attributs) 

def test_format_html(self):
        """
        Test: format_html
        url: https://github.com/django/django/blob/stable/1.8.x/tests/utils_tests/test_html.py#L44-L53

        """

        from django.utils import html

        from compat import format_html

        self.assertEqual(
            format_html("{0} {1} {third} {fourth}",
                             "< Dangerous >",
                             html.mark_safe("<b>safe</b>"),
                             third="< dangerous again",
                             fourth=html.mark_safe("<i>safe again</i>")
                             ),
            "&lt; Dangerous &gt; <b>safe</b> &lt; dangerous again <i>safe again</i>"
        ) 

def _execute_wrapper(self, method, query, args):
        """Wrapper around execute() and executemany()"""
        try:
            return method(query, args)
        except (mysql.connector.ProgrammingError) as err:
            six.reraise(utils.ProgrammingError,
                        utils.ProgrammingError(err.msg), sys.exc_info()[2])
        except (mysql.connector.IntegrityError) as err:
            six.reraise(utils.IntegrityError,
                        utils.IntegrityError(err.msg), sys.exc_info()[2])
        except mysql.connector.OperationalError as err:
            # Map some error codes to IntegrityError, since they seem to be
            # misclassified and Django would prefer the more logical place.
            if err.args[0] in self.codes_for_integrityerror:
                six.reraise(utils.IntegrityError,
                            utils.IntegrityError(err.msg), sys.exc_info()[2])
            else:
                six.reraise(utils.DatabaseError,
                            utils.DatabaseError(err.msg), sys.exc_info()[2])
        except mysql.connector.DatabaseError as err:
            six.reraise(utils.DatabaseError,
                        utils.DatabaseError(err.msg), sys.exc_info()[2]) 

def test_json_attributes(self):
        """test the json storage of ``atrributs`` in ``_attributs``"""
        provider = models.FederatedIendityProvider.objects.get(suffix="example.com")
        user = models.FederatedUser.objects.create(
            username=settings.CAS_TEST_USER,
            provider=provider,
            attributs=settings.CAS_TEST_ATTRIBUTES,
            ticket=""
        )
        self.assertEqual(utils.json_encode(settings.CAS_TEST_ATTRIBUTES), user._attributs)
        user.delete()
        user = models.FederatedUser.objects.create(
            username=settings.CAS_TEST_USER,
            provider=provider,
            ticket=""
        )
        self.assertIsNone(user._attributs)
        self.assertIsNone(user.attributs) 

def test_saml_bad_target(self):
        """test with a valid ticket, but using a bad target, validation should fail"""
        bad_target = "https://www.example.org"
        ticket = get_user_ticket_request(self.service)[1]

        client = Client()
        response = client.post(
            '/samlValidate?TARGET=%s' % bad_target,
            self.xml_template % {
                'ticket': ticket.value,
                'request_id': utils.gen_saml_id(),
                'issue_instant': timezone.now().isoformat()
            },
            content_type="text/xml; encoding='utf-8'"
        )
        self.assert_error(
            response,
            "AuthnFailed",
            'TARGET %s does not match ticket service' % bad_target
        ) 

def test_saml_bad_ticket_prefix(self):
        """test validation with a bad ticket prefix. Validation should fail with 'AuthnFailed'"""
        bad_ticket = "RANDOM-NOT-BEGINING-WITH-ST-OR-ST"
        client = Client()
        response = client.post(
            '/samlValidate?TARGET=%s' % self.service,
            self.xml_template % {
                'ticket': bad_ticket,
                'request_id': utils.gen_saml_id(),
                'issue_instant': timezone.now().isoformat()
            },
            content_type="text/xml; encoding='utf-8'"
        )
        self.assert_error(
            response,
            "AuthnFailed",
            'ticket %s should begin with PT- or ST-' % bad_ticket
        ) 

def test_saml_bad_ticket(self):
        """test validation with a bad ST and a bad PT, validation should fail"""
        tickets = [utils.gen_st(), utils.gen_pt()]

        for ticket in tickets:
            client = Client()
            response = client.post(
                '/samlValidate?TARGET=%s' % self.service,
                self.xml_template % {
                    'ticket': ticket,
                    'request_id': utils.gen_saml_id(),
                    'issue_instant': timezone.now().isoformat()
                },
                content_type="text/xml; encoding='utf-8'"
            )
            self.assert_error(
                response,
                "AuthnFailed",
                'ticket %s not found' % ticket
            ) 

def test_saml_ok_user_field(self):
        """test with a valid(ticket, service), use a attributes as transmitted username"""
        for (service, username) in [
            (self.service_field_needed_success, settings.CAS_TEST_ATTRIBUTES['alias'][0]),
            (self.service_field_needed_success_alt, settings.CAS_TEST_ATTRIBUTES['nom'])
        ]:
            ticket = get_user_ticket_request(service)[1]

            client = Client()
            response = client.post(
                '/samlValidate?TARGET=%s' % service,
                self.xml_template % {
                    'ticket': ticket.value,
                    'request_id': utils.gen_saml_id(),
                    'issue_instant': timezone.now().isoformat()
                },
                content_type="text/xml; encoding='utf-8'"
            )
            self.assert_success(response, username, {}) 

def test_saml_ok(self):
        """
            test with a valid (ticket, service), with a ST and a PT,
            the username and all attributes are transmited"""
        tickets = [
            # return a ServiceTicket (standard ticket) waiting for validation
            get_user_ticket_request(self.service)[1],
            # return a PT waiting for validation
            get_proxy_ticket(self.service)
        ]

        for ticket in tickets:
            client = Client()
            # we send the POST validation requests
            response = client.post(
                '/samlValidate?TARGET=%s' % self.service,
                self.xml_template % {
                    'ticket': ticket.value,
                    'request_id': utils.gen_saml_id(),
                    'issue_instant': timezone.now().isoformat()
                },
                content_type="text/xml; encoding='utf-8'"
            )
            # and it should succeed
            self.assert_success(response, settings.CAS_TEST_USER, settings.CAS_TEST_ATTRIBUTES) 

def _execute_wrapper(self, method, query, args):
        """Wrapper around execute() and executemany()"""
        try:
            return method(query, args)
        except (PyMysqlPool.mysql.connector.ProgrammingError) as err:
            six.reraise(utils.ProgrammingError,
                        utils.ProgrammingError(err.msg), sys.exc_info()[2])
        except (PyMysqlPool.mysql.connector.IntegrityError) as err:
            six.reraise(utils.IntegrityError,
                        utils.IntegrityError(err.msg), sys.exc_info()[2])
        except PyMysqlPool.mysql.connector.OperationalError as err:
            # Map some error codes to IntegrityError, since they seem to be
            # misclassified and Django would prefer the more logical place.
            if err.args[0] in self.codes_for_integrityerror:
                six.reraise(utils.IntegrityError,
                            utils.IntegrityError(err.msg), sys.exc_info()[2])
            else:
                six.reraise(utils.DatabaseError,
                            utils.DatabaseError(err.msg), sys.exc_info()[2])
        except PyMysqlPool.mysql.connector.DatabaseError as err:
            six.reraise(utils.DatabaseError,
                        utils.DatabaseError(err.msg), sys.exc_info()[2]) 

def test_dates_with_aggregation(self):
        """
        .dates() returns a distinct set of dates when applied to a
        QuerySet with aggregation.

        Refs #18056. Previously, .dates() would return distinct (date_kind,
        aggregation) sets, in this case (year, num_authors), so 2008 would be
        returned twice because there are books from 2008 with a different
        number of authors.
        """
        srv_ver = connection.get_server_version()
        if (12, 0, 0, 0) <= srv_ver < (13, 0, 0, 0):
            # this test fails on SQL server 2014
            self.skipTest("TODO fix django.db.utils.OperationalError: ORDER BY items must appear in the select list if SELECT DISTINCT is specified.")
        dates = Book.objects.annotate(num_authors=Count("authors")).dates('pubdate', 'year')
        self.assertQuerysetEqual(
            dates, [
                "datetime.date(1991, 1, 1)",
                "datetime.date(1995, 1, 1)",
                "datetime.date(2007, 1, 1)",
                "datetime.date(2008, 1, 1)"
            ]
        ) 

def utils(django_utils_function):
    def decorator(func):
        util_function = helper.deep_getattribute(django_utils, django_utils_function)
        if isinstance(util_function, helper.Nothing):
            raise Exception('Function {} not exist on django.utils module.'.format(django_utils_function))

        @wraps(func)
        def wrapper(*args, **kwargs):
            return util_function(func(*args, **kwargs))

        return wrapper

    return decorator 

def process(self, stack, stream):
        """Process the token stream"""
        for token_type, value in stream:
            is_keyword = token_type in sqlparse.tokens.Keyword
            if is_keyword:
                yield sqlparse.tokens.Text, '<strong>'
            yield token_type, django.utils.html.escape(value)
            if is_keyword:
                yield sqlparse.tokens.Text, '</strong>' 

def test_clean_deleted_sessions(self):
        """
            tests for clean_deleted_sessions that should delete object for which matching session
            do not exists anymore
        """
        if django.VERSION >= (1, 8):
            client1 = Client()
            client2 = Client()
            client1.get("/login")
            client2.get("/login")
            session = client2.session
            session['authenticated'] = True
            session.save()
            models.FederateSLO.objects.create(
                username="test1@example.com",
                session_key=client1.session.session_key,
                ticket=utils.gen_st()
            )
            models.FederateSLO.objects.create(
                username="test2@example.com",
                session_key=client2.session.session_key,
                ticket=utils.gen_st()
            )
            self.assertEqual(len(models.FederateSLO.objects.all()), 2)
            models.FederateSLO.clean_deleted_sessions()
            self.assertEqual(len(models.FederateSLO.objects.all()), 1)
            with self.assertRaises(models.FederateSLO.DoesNotExist):
                models.FederateSLO.objects.get(username="test1@example.com") 

def test_durationfield_add(self):
        self.skipTest("TODO fix django.db.utils.ProgrammingError: Incorrect syntax near '1000000'.")
        # (0.001) QUERY = 'SELECT [expressions_experiment].[id], [expressions_experiment].[name], [expressions_experiment].[assigned], [expressions_experiment].[completed], [expressions_experiment].[estimated_time], [expressions_experiment].[start], [expressions_experiment].[end] FROM [expressions_experiment] WHERE [expressions_experiment].[start] = ((DATEADD(MICROSECOND, ([expressions_experiment].[estimated_time] %% 1000000), CAST(DATEADD(SECOND, ([expressions_experiment].[estimated_time] / 1000000), CAST([expressions_experiment].[start] as datetime2)) as datetime2)))) ORDER BY [expressions_experiment].[name] ASC' - PARAMS = (); args=()
        zeros = [e.name for e in Experiment.objects.filter(start=F('start') + F('estimated_time'))]
        self.assertEqual(zeros, ['e0'])

        end_less = [e.name for e in Experiment.objects.filter(end__lt=F('start') + F('estimated_time'))]
        self.assertEqual(end_less, ['e2'])

        delta_math = [
            e.name for e in
            Experiment.objects.filter(end__gte=F('start') + F('estimated_time') + datetime.timedelta(hours=1))
        ]
        self.assertEqual(delta_math, ['e4']) 

def test_invalid_operator(self):
        self.skipTest("TODO fix django.db.utils.ProgrammingError: Incorrect syntax near '1000000'.")
        # throws django.db.utils.ProgrammingError instead of DatabaseError
        with self.assertRaises(DatabaseError):
            list(Experiment.objects.filter(start=F('start') * datetime.timedelta(0))) 

def test_in_lookup_allows_F_expressions_and_expressions_for_datetimes(self):
        self.skipTest("TODO fix django.db.utils.OperationalError: Conversion failed when converting date and/or time from character string.")
        # (0.012) QUERY = 'SELECT [expressions_result].[id], [expressions_result].[experiment_id], [expressions_result].[result_time] FROM [expressions_result] INNER JOIN [expressions_experiment] ON ([expressions_result].[experiment_id] = [expressions_experiment].[id]) WHERE [expressions_result].[result_time] BETWEEN %s AND %s' - PARAMS = ('F(experiment__start)', 'F(experiment__end)'); args=('F(experiment__start)', 'F(experiment__end)')
        start = datetime.datetime(2016, 2, 3, 15, 0, 0)
        end = datetime.datetime(2016, 2, 5, 15, 0, 0)
        experiment_1 = Experiment.objects.create(
            name='Integrity testing',
            assigned=start.date(),
            start=start,
            end=end,
            completed=end.date(),
            estimated_time=end - start,
        )
        experiment_2 = Experiment.objects.create(
            name='Taste testing',
            assigned=start.date(),
            start=start,
            end=end,
            completed=end.date(),
            estimated_time=end - start,
        )
        Result.objects.create(
            experiment=experiment_1,
            result_time=datetime.datetime(2016, 2, 4, 15, 0, 0),
        )
        Result.objects.create(
            experiment=experiment_1,
            result_time=datetime.datetime(2016, 3, 10, 2, 0, 0),
        )
        Result.objects.create(
            experiment=experiment_2,
            result_time=datetime.datetime(2016, 1, 8, 5, 0, 0),
        )

        within_experiment_time = [F('experiment__start'), F('experiment__end')]
        queryset = Result.objects.filter(result_time__range=within_experiment_time)
        self.assertQuerysetEqual(queryset, ["<Result: Result at 2016-02-04 15:00:00>"])

        within_experiment_time = [F('experiment__start'), F('experiment__end')]
        queryset = Result.objects.filter(result_time__range=within_experiment_time)
        self.assertQuerysetEqual(queryset, ["<Result: Result at 2016-02-04 15:00:00>"]) 

def cleanup_wooey_jobs(**kwargs):
    from django.utils import timezone
    from .models import WooeyJob

    cleanup_settings = wooey_settings.WOOEY_JOB_EXPIRATION
    anon_settings = cleanup_settings.get('anonymous')
    now = timezone.now()
    if anon_settings:
        WooeyJob.objects.filter(user=None, created_date__lte=now-anon_settings).delete()
    user_settings = cleanup_settings.get('user')
    if user_settings:
        WooeyJob.objects.filter(user__isnull=False, created_date__lte=now-user_settings).delete() 

def get_latest_script(script_version):
    """Downloads the latest script version to the local storage.

    :param script_version: :py:class:`~wooey.models.core.ScriptVersion`
    :return: boolean
        Returns true if a new version was downloaded.
    """
    script_path = script_version.script_path
    local_storage = utils.get_storage(local=True)
    script_exists = local_storage.exists(script_path.name)
    if not script_exists:
        local_storage.save(script_path.name, script_path.file)
        return True
    else:
        # If script exists, make sure the version is valid, otherwise fetch a new one
        script_contents = local_storage.open(script_path.name).read()
        script_checksum = utils.get_checksum(buff=script_contents)
        if script_checksum != script_version.checksum:
            tf = tempfile.TemporaryFile()
            with tf:
                tf.write(script_contents)
                tf.seek(0)
                local_storage.delete(script_path.name)
                local_storage.save(script_path.name, tf)
                return True
    return False 

def execute(self, *args, **options):
        """
        Try to execute this command, performing model validation if
        needed (as controlled by the attribute
        ``self.requires_model_validation``, except if force-skipped).
        """

        # Switch to English, because django-admin.py creates database content
        # like permissions, and those shouldn't contain any translations.
        # But only do this if we can assume we have a working settings file,
        # because django.utils.translation requires settings.
        saved_lang = None
        self.stdout = OutputWrapper(options.get('stdout', sys.stdout))
        self.stderr = OutputWrapper(options.get('stderr', sys.stderr), self.style.ERROR)

        if self.can_import_settings:
            from django.utils import translation
            saved_lang = translation.get_language()
            translation.activate('en-us')

        try:
            if self.requires_model_validation and not options.get('skip_validation'):
                self.validate()
            output = self.handle(*args, **options)
            if output:
                if self.output_transaction:
                    # This needs to be imported here, because it relies on
                    # settings.
                    from django.db import connections, DEFAULT_DB_ALIAS
                    connection = connections[options.get('database', DEFAULT_DB_ALIAS)]
                    if connection.ops.start_transaction_sql():
                        self.stdout.write(self.style.SQL_KEYWORD(connection.ops.start_transaction_sql()))
                self.stdout.write(output)
                if self.output_transaction:
                    self.stdout.write('\n' + self.style.SQL_KEYWORD("COMMIT;"))
        finally:
            if saved_lang is not None:
                translation.activate(saved_lang) 

def pytest_configure(config):
    deprecation = config.getoption('deprecation')

    only_wagtail = r'^wagtail(\.|$)'
    if deprecation == 'all':
        # Show all deprecation warnings from all packages
        warnings.simplefilter('default', DeprecationWarning)
        warnings.simplefilter('default', PendingDeprecationWarning)
    elif deprecation == 'pending':
        # Show all deprecation warnings from wagtail
        warnings.filterwarnings('default', category=DeprecationWarning, module=only_wagtail)
        warnings.filterwarnings('default', category=PendingDeprecationWarning, module=only_wagtail)
    elif deprecation == 'imminent':
        # Show only imminent deprecation warnings from wagtail
        warnings.filterwarnings('default', category=DeprecationWarning, module=only_wagtail)
    elif deprecation == 'none':
        # Deprecation warnings are ignored by default
        pass

    if config.getoption('postgres'):
        os.environ['DATABASE_ENGINE'] = 'django.db.backends.postgresql'

    # Setup django after processing the pytest arguments so that the env
    # variables are available in the settings
    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'wagtail.tests.settings')
    django.setup()

    # Activate a language: This affects HTTP header HTTP_ACCEPT_LANGUAGE sent by
    # the Django test client.
    from django.utils import translation
    translation.activate("en")

    from wagtail.tests.settings import MEDIA_ROOT, STATIC_ROOT
    shutil.rmtree(STATIC_ROOT, ignore_errors=True)
    shutil.rmtree(MEDIA_ROOT, ignore_errors=True) 

def statistics_work():
    connect.delete('WORK')
    work_dist = dict()
    import django
    now = django.utils.timezone.now().date()
    for i in range(6, -1, -1):
        start_day = now - datetime.timedelta(days=i)
        end_day = now - datetime.timedelta(days=i-1)
        weekday = start_day.weekday()
        work_dist[week_list[int(weekday)]] = Push_Mission.objects.filter(
            create_time__gt=start_day, create_time__lt=end_day
        ).count()
    for key, value in work_dist.items():
        connect.hset('WORK', key, value) 

def debug(key, value):
        from django.utils.termcolors import colorize

        if value:
            sys.stdout.write(colorize(key, fg='green'))
            sys.stdout.write(": ")
            sys.stdout.write(colorize(repr(value), fg='white'))
            sys.stdout.write("\n") 

def download(self, url):
        """
        Downloads the given URL and returns the file name.
        """
        def cleanup_url(url):
            tmp = url.rstrip('/')
            filename = tmp.split('/')[-1]
            if url.endswith('/'):
                display_url  = tmp + '/'
            else:
                display_url = url
            return filename, display_url

        prefix = 'django_%s_template_' % self.app_or_project
        tempdir = tempfile.mkdtemp(prefix=prefix, suffix='_download')
        self.paths_to_remove.append(tempdir)
        filename, display_url = cleanup_url(url)

        if self.verbosity >= 2:
            self.stdout.write("Downloading %s\n" % display_url)
        try:
            the_path, info = urlretrieve(url, path.join(tempdir, filename))
        except IOError as e:
            raise CommandError("couldn't download URL %s to %s: %s" %
                               (url, filename, e))

        used_name = the_path.split('/')[-1]

        # Trying to get better name from response headers
        content_disposition = info.get('content-disposition')
        if content_disposition:
            _, params = cgi.parse_header(content_disposition)
            guessed_filename = params.get('filename') or used_name
        else:
            guessed_filename = used_name

        # Falling back to content type guessing
        ext = self.splitext(guessed_filename)[1]
        content_type = info.get('content-type')
        if not ext and content_type:
            ext = mimetypes.guess_extension(content_type)
            if ext:
                guessed_filename += ext

        # Move the temporary file to a filename that has better
        # chances of being recognnized by the archive utils
        if used_name != guessed_filename:
            guessed_path = path.join(tempdir, guessed_filename)
            shutil.move(the_path, guessed_path)
            return guessed_path

        # Giving up
        return the_path 

def check_constraints(self, table_names=None):
        """Check rows in tables for invalid foreign key references

        Checks each table name in `table_names` for rows with invalid foreign
        key references. This method is intended to be used in conjunction with
        `disable_constraint_checking()` and `enable_constraint_checking()`, to
        determine if rows with invalid references were entered while
        constraint checks were off.

        Raises an IntegrityError on the first invalid foreign key reference
        encountered (if any) and provides detailed information about the
        invalid reference in the error message.

        Backends can override this method if they can more directly apply
        constraint checking (e.g. via "SET CONSTRAINTS ALL IMMEDIATE")
        """
        ref_query = """
            SELECT REFERRING.`{0}`, REFERRING.`{1}` FROM `{2}` as REFERRING
            LEFT JOIN `{3}` as REFERRED
            ON (REFERRING.`{4}` = REFERRED.`{5}`)
            WHERE REFERRING.`{6}` IS NOT NULL AND REFERRED.`{7}` IS NULL"""
        cursor = self.cursor()
        if table_names is None:
            table_names = self.introspection.table_names(cursor)
        for table_name in table_names:
            primary_key_column_name = \
                self.introspection.get_primary_key_column(cursor, table_name)
            if not primary_key_column_name:
                continue
            key_columns = self.introspection.get_key_columns(cursor,
                                                             table_name)
            for column_name, referenced_table_name, referenced_column_name \
                    in key_columns:
                cursor.execute(ref_query.format(primary_key_column_name,
                                                column_name, table_name,
                                                referenced_table_name,
                                                column_name,
                                                referenced_column_name,
                                                column_name,
                                                referenced_column_name))
                for bad_row in cursor.fetchall():
                    msg = ("The row in table '{0}' with primary key '{1}' has "
                           "an invalid foreign key: {2}.{3} contains a value "
                           "'{4}' that does not have a corresponding value in "
                           "{5}.{6}.".format(table_name, bad_row[0],
                                             table_name, column_name,
                                             bad_row[1], referenced_table_name,
                                             referenced_column_name))
                    raise utils.IntegrityError(msg) 

def download(self, url):
        """
        Downloads the given URL and returns the file name.
        """
        def cleanup_url(url):
            tmp = url.rstrip('/')
            filename = tmp.split('/')[-1]
            if url.endswith('/'):
                display_url = tmp + '/'
            else:
                display_url = url
            return filename, display_url

        prefix = 'django_%s_template_' % self.app_or_project
        tempdir = tempfile.mkdtemp(prefix=prefix, suffix='_download')
        self.paths_to_remove.append(tempdir)
        filename, display_url = cleanup_url(url)

        if self.verbosity >= 2:
            self.stdout.write("Downloading %s\n" % display_url)
        try:
            the_path, info = urlretrieve(url, path.join(tempdir, filename))
        except IOError as e:
            raise CommandError("couldn't download URL %s to %s: %s" %
                               (url, filename, e))

        used_name = the_path.split('/')[-1]

        # Trying to get better name from response headers
        content_disposition = info.get('content-disposition')
        if content_disposition:
            _, params = cgi.parse_header(content_disposition)
            guessed_filename = params.get('filename') or used_name
        else:
            guessed_filename = used_name

        # Falling back to content type guessing
        ext = self.splitext(guessed_filename)[1]
        content_type = info.get('content-type')
        if not ext and content_type:
            ext = mimetypes.guess_extension(content_type)
            if ext:
                guessed_filename += ext

        # Move the temporary file to a filename that has better
        # chances of being recognized by the archive utils
        if used_name != guessed_filename:
            guessed_path = path.join(tempdir, guessed_filename)
            shutil.move(the_path, guessed_path)
            return guessed_path

        # Giving up
        return the_path 

def execute(self, *args, **options):
        """
        Try to execute this command, performing system checks if needed (as
        controlled by attributes ``self.requires_system_checks`` and
        ``self.requires_model_validation``, except if force-skipped).
        """
        if options.get('no_color'):
            self.style = no_style()
            self.stderr.style_func = None
        if options.get('stdout'):
            self.stdout = OutputWrapper(options['stdout'])
        if options.get('stderr'):
            self.stderr = OutputWrapper(options.get('stderr'), self.stderr.style_func)

        saved_locale = None
        if not self.leave_locale_alone:
            # Only mess with locales if we can assume we have a working
            # settings file, because django.utils.translation requires settings
            # (The final saying about whether the i18n machinery is active will be
            # found in the value of the USE_I18N setting)
            if not self.can_import_settings:
                raise CommandError("Incompatible values of 'leave_locale_alone' "
                                   "(%s) and 'can_import_settings' (%s) command "
                                   "options." % (self.leave_locale_alone,
                                                 self.can_import_settings))
            # Deactivate translations, because django-admin creates database
            # content like permissions, and those shouldn't contain any
            # translations.
            from django.utils import translation
            saved_locale = translation.get_language()
            translation.deactivate_all()

        try:
            if (self.requires_system_checks and
                    not options.get('skip_validation') and  # Remove at the end of deprecation for `skip_validation`.
                    not options.get('skip_checks')):
                self.check()
            output = self.handle(*args, **options)
            if output:
                if self.output_transaction:
                    # This needs to be imported here, because it relies on
                    # settings.
                    from django.db import connections, DEFAULT_DB_ALIAS
                    connection = connections[options.get('database', DEFAULT_DB_ALIAS)]
                    if connection.ops.start_transaction_sql():
                        self.stdout.write(self.style.SQL_KEYWORD(connection.ops.start_transaction_sql()))
                self.stdout.write(output)
                if self.output_transaction:
                    self.stdout.write('\n' + self.style.SQL_KEYWORD(connection.ops.end_transaction_sql()))
        finally:
            if saved_locale is not None:
                translation.activate(saved_locale) 

def check_constraints(self, table_names=None):
        """Check rows in tables for invalid foreign key references

        Checks each table name in `table_names` for rows with invalid foreign
        key references. This method is intended to be used in conjunction with
        `disable_constraint_checking()` and `enable_constraint_checking()`, to
        determine if rows with invalid references were entered while
        constraint checks were off.

        Raises an IntegrityError on the first invalid foreign key reference
        encountered (if any) and provides detailed information about the
        invalid reference in the error message.

        Backends can override this method if they can more directly apply
        constraint checking (e.g. via "SET CONSTRAINTS ALL IMMEDIATE")
        """
        ref_query = """
            SELECT REFERRING.`{0}`, REFERRING.`{1}` FROM `{2}` as REFERRING
            LEFT JOIN `{3}` as REFERRED
            ON (REFERRING.`{4}` = REFERRED.`{5}`)
            WHERE REFERRING.`{6}` IS NOT NULL AND REFERRED.`{7}` IS NULL"""
        cursor = self.cursor()
        if table_names is None:
            table_names = self.introspection.table_names(cursor)
        for table_name in table_names:
            primary_key_column_name = \
                self.introspection.get_primary_key_column(cursor, table_name)
            if not primary_key_column_name:
                continue
            key_columns = self.introspection.get_key_columns(cursor,
                                                             table_name)
            for column_name, referenced_table_name, referenced_column_name \
                    in key_columns:
                cursor.execute(ref_query.format(primary_key_column_name,
                                                column_name, table_name,
                                                referenced_table_name,
                                                column_name,
                                                referenced_column_name,
                                                column_name,
                                                referenced_column_name))
                for bad_row in cursor.fetchall():
                    msg = ("The row in table '{0}' with primary key '{1}' has "
                           "an invalid foreign key: {2}.{3} contains a value "
                           "'{4}' that does not have a corresponding value in "
                           "{5}.{6}.".format(table_name, bad_row[0],
                                             table_name, column_name,
                                             bad_row[1], referenced_table_name,
                                             referenced_column_name))
                    raise utils.IntegrityError(msg)