main.py

# Copyright 2014 The Oppia Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS-IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""URL routing definitions, and some basic error/warmup handlers."""

from __future__ import absolute_import  # pylint: disable=import-only-modules
from __future__ import unicode_literals  # pylint: disable=import-only-modules

import logging
from constants import constants

from core.controllers import acl_decorators
from core.controllers import admin
from core.controllers import base
from core.controllers import classifier
from core.controllers import classroom
from core.controllers import collection_editor
from core.controllers import collection_viewer
from core.controllers import concept_card_viewer
from core.controllers import contributor_dashboard
from core.controllers import creator_dashboard
from core.controllers import custom_landing_pages
from core.controllers import editor
from core.controllers import email_dashboard
from core.controllers import features
from core.controllers import feedback
from core.controllers import improvements
from core.controllers import learner_dashboard
from core.controllers import learner_playlist
from core.controllers import library
from core.controllers import moderator
from core.controllers import pages
from core.controllers import platform_feature
from core.controllers import practice_sessions
from core.controllers import profile
from core.controllers import question_editor
from core.controllers import questions_list
from core.controllers import reader
from core.controllers import recent_commits
from core.controllers import resources
from core.controllers import review_tests
from core.controllers import skill_editor
from core.controllers import skill_mastery
from core.controllers import story_editor
from core.controllers import story_viewer
from core.controllers import subscriptions
from core.controllers import subtopic_viewer
from core.controllers import suggestion
from core.controllers import topic_editor
from core.controllers import topic_viewer
from core.controllers import topics_and_skills_dashboard
from core.controllers import voice_artist
from core.domain import user_services
from core.platform import models
from core.platform.auth import firebase_auth_services
import feconf

from mapreduce import main as mapreduce_main
from mapreduce import parameters as mapreduce_parameters
import webapp2
from webapp2_extras import routes

transaction_services = models.Registry.import_transaction_services()

# Suppress debug logging for chardet. See https://stackoverflow.com/a/48581323.
# Without this, a lot of unnecessary debug logs are printed in error logs,
# which makes it tiresome to identify the actual error.
logging.getLogger(name='chardet.charsetprober').setLevel(logging.INFO)


class FrontendErrorHandler(base.BaseHandler):
    """Handles errors arising from the frontend."""

    REQUIRE_PAYLOAD_CSRF_CHECK = False

    @acl_decorators.open_access
    def post(self):
        """Records errors reported by the frontend."""
        logging.error('Frontend error: %s' % self.payload.get('error'))
        self.render_json(self.values)


class WarmupPage(base.BaseHandler):
    """Handles warmup requests."""

    @acl_decorators.open_access
    def get(self):
        """Handles GET warmup requests."""
        pass


class HomePageRedirectPage(base.BaseHandler):
    """When a request is made to '/', check the user's login status, and
    redirect them appropriately.
    """

    @acl_decorators.open_access
    def get(self):
        if self.user_id and user_services.has_fully_registered_account(
                self.user_id):
            user_settings = user_services.get_user_settings(
                self.user_id)
            default_dashboard = user_settings.default_dashboard
            if default_dashboard == constants.DASHBOARD_TYPE_CREATOR:
                self.redirect(feconf.CREATOR_DASHBOARD_URL)
            else:
                self.redirect(feconf.LEARNER_DASHBOARD_URL)
        else:
            self.render_template('splash-page.mainpage.html')


class SplashRedirectPage(base.BaseHandler):
    """Redirect the old splash URL, '/splash' to the new one, '/'."""

    @acl_decorators.open_access
    def get(self):
        self.redirect('/')


def get_redirect_route(regex_route, handler, defaults=None):
    """Returns a route that redirects /foo/ to /foo.

    Warning: this method strips off parameters after the trailing slash. URLs
    with parameters should be formulated without the trailing slash.

    Args:
        regex_route: unicode. A raw string representing a route.
        handler: BaseHandler. A callable to handle the route.
        defaults: dict. Optional defaults parameter to be passed
            into the RedirectRoute object.

    Returns:
        RedirectRoute. A RedirectRoute object for redirects.
    """
    if defaults is None:
        defaults = {}
    name = regex_route.replace('/', '_')
    return routes.RedirectRoute(
        regex_route, handler, name, strict_slash=True, defaults=defaults)


def authorization_wrapper(self, *args, **kwargs):
    """This request handler wrapper only admits internal requests from
    taskqueue workers. If the request is invalid, it leads to a 403 Error page.
    """
    # Internal requests should have an "X-AppEngine-TaskName" header
    # (see cloud.google.com/appengine/docs/standard/python/taskqueue/push/).
    if 'X-AppEngine-TaskName' not in self.request.headers:
        self.response.out.write('Forbidden')
        self.response.set_status(403)
        return
    self.real_dispatch(*args, **kwargs)


def ui_access_wrapper(self, *args, **kwargs):
    """This request handler wrapper directly serves UI pages
    for MapReduce dashboards.
    """
    self.real_dispatch(*args, **kwargs)


MAPREDUCE_HANDLERS = []

for path, handler_class in mapreduce_main.create_handlers_map():
    if path.startswith('.*/pipeline'):
        if 'pipeline/rpc/' in path or path == '.*/pipeline(/.+)':
            path = path.replace('.*/pipeline', '/mapreduce/ui/pipeline')
        else:
            path = path.replace('.*/pipeline', '/mapreduce/worker/pipeline')
    else:
        if '_callback' in path:
            path = path.replace('.*', '/mapreduce/worker', 1)
        elif '/list_configs' in path:
            continue
        else:
            path = path.replace('.*', '/mapreduce/ui', 1)

    if '/ui/' in path or path.endswith('/ui'):
        if (hasattr(handler_class, 'dispatch') and
                not hasattr(handler_class, 'real_dispatch')):
            handler_class.real_dispatch = handler_class.dispatch
            handler_class.dispatch = ui_access_wrapper
        MAPREDUCE_HANDLERS.append((path, handler_class))
    else:
        if (hasattr(handler_class, 'dispatch') and
                not hasattr(handler_class, 'real_dispatch')):
            handler_class.real_dispatch = handler_class.dispatch
            handler_class.dispatch = authorization_wrapper
        MAPREDUCE_HANDLERS.append((path, handler_class))

# Tell map/reduce internals that this is now the base path to use.
mapreduce_parameters.config.BASE_PATH = '/mapreduce/worker'

# Register the URLs with the classes responsible for handling them.
URLS = MAPREDUCE_HANDLERS + [
    get_redirect_route(r'/_ah/warmup', WarmupPage),
    get_redirect_route(r'/', HomePageRedirectPage),
    get_redirect_route(r'/splash', SplashRedirectPage),

    get_redirect_route(r'/foundation', pages.FoundationRedirectPage),
    get_redirect_route(r'/credits', pages.AboutRedirectPage),
    get_redirect_route(r'/participate', pages.TeachRedirectPage),
    get_redirect_route(r'/site_guidelines', pages.TeachRedirectPage),
    get_redirect_route(r'/console_errors', pages.ConsoleErrorPage),

    get_redirect_route(r'/forum', pages.ForumRedirectPage),

    get_redirect_route(r'%s' % feconf.ADMIN_URL, admin.AdminPage),
    get_redirect_route(r'/adminhandler', admin.AdminHandler),
    get_redirect_route(r'/adminrolehandler', admin.AdminRoleHandler),
    get_redirect_route(
        r'/adminsuperadminhandler', admin.AdminSuperAdminPrivilegesHandler),
    get_redirect_route(
        r'/memorycacheadminhandler', admin.MemoryCacheAdminHandler),
    get_redirect_route(r'/adminjoboutput', admin.AdminJobOutputHandler),
    get_redirect_route(
        r'/admintopicscsvdownloadhandler',
        admin.AdminTopicsCsvFileDownloader),
    get_redirect_route(
        r'/addcontributionrightshandler',
        admin.AddContributionRightsHandler),
    get_redirect_route(
        r'/removecontributionrightshandler',
        admin.RemoveContributionRightsHandler),
    get_redirect_route(
        r'/getcontributorusershandler',
        admin.ContributorUsersListHandler),
    get_redirect_route(
        r'/contributionrightsdatahandler',
        admin.ContributionRightsDataHandler),
    get_redirect_route(
        r'%s' % feconf.CONTRIBUTOR_DASHBOARD_URL,
        contributor_dashboard.ContributorDashboardPage),

    get_redirect_route(
        '/notifications_dashboard',
        creator_dashboard.OldNotificationsDashboardRedirectPage),
    get_redirect_route(
        '/contributor_dashboard',
        creator_dashboard.OldContributorDashboardRedirectPage),
    get_redirect_route(
        feconf.NOTIFICATIONS_DASHBOARD_URL,
        creator_dashboard.NotificationsDashboardPage),
    get_redirect_route(
        r'/notificationsdashboardhandler/data',
        creator_dashboard.NotificationsDashboardHandler),
    get_redirect_route(
        r'/notificationshandler', creator_dashboard.NotificationsHandler),
    get_redirect_route(
        '/creator_dashboard',
        creator_dashboard.OldCreatorDashboardRedirectPage),
    get_redirect_route(
        r'%s' % feconf.CREATOR_DASHBOARD_URL,
        creator_dashboard.CreatorDashboardPage),
    get_redirect_route(
        r'%s' % feconf.CREATOR_DASHBOARD_DATA_URL,
        creator_dashboard.CreatorDashboardHandler),
    get_redirect_route(
        r'%s' % feconf.NEW_EXPLORATION_URL,
        creator_dashboard.NewExplorationHandler),
    get_redirect_route(
        r'%s' % feconf.NEW_COLLECTION_URL,
        creator_dashboard.NewCollectionHandler),
    get_redirect_route(
        r'%s' % feconf.FRACTIONS_LANDING_PAGE_URL,
        custom_landing_pages.FractionLandingRedirectPage),
    get_redirect_route(
        r'/learn/maths/<topic>', custom_landing_pages.TopicLandingRedirectPage),
    get_redirect_route(
        r'%s/<opportunity_type>' % feconf.CONTRIBUTOR_OPPORTUNITIES_DATA_URL,
        contributor_dashboard.ContributionOpportunitiesHandler),
    get_redirect_route(
        r'/gettranslatabletexthandler',
        contributor_dashboard.TranslatableTextHandler),
    get_redirect_route(
        r'%s' % feconf.MACHINE_TRANSLATION_DATA_URL,
        contributor_dashboard.MachineTranslationStateTextsHandler),
    get_redirect_route(
        r'/usercontributionrightsdatahandler',
        contributor_dashboard.UserContributionRightsDataHandler),
    get_redirect_route(
        r'/retrivefeaturedtranslationlanguages',
        contributor_dashboard.FeaturedTranslationLanguagesHandler),
    get_redirect_route(
        r'%s' % feconf.NEW_SKILL_URL,
        topics_and_skills_dashboard.NewSkillHandler),
    get_redirect_route(
        r'%s' % feconf.NEW_QUESTION_URL,
        question_editor.QuestionCreationHandler),
    get_redirect_route(
        r'%s/<comma_separated_skill_ids>' % feconf.QUESTIONS_LIST_URL_PREFIX,
        questions_list.QuestionsListHandler),
    get_redirect_route(
        r'%s/<comma_separated_skill_ids>' % feconf.QUESTION_COUNT_URL_PREFIX,
        questions_list.QuestionCountDataHandler),
    get_redirect_route(
        r'%s/practice/session' % feconf.TOPIC_VIEWER_URL_PREFIX,
        practice_sessions.PracticeSessionsPage),
    get_redirect_route(
        r'%s/<classroom_url_fragment>/<topic_url_fragment>' %
        feconf.PRACTICE_SESSION_DATA_URL_PREFIX,
        practice_sessions.PracticeSessionsPageDataHandler),
    get_redirect_route(
        r'%s/<classroom_url_fragment>/<topic_url_fragment>'
        r'/<story_url_fragment>' % feconf.REVIEW_TEST_DATA_URL_PREFIX,
        review_tests.ReviewTestsPageDataHandler),
    get_redirect_route(
        r'%s/review-test/<story_url_fragment>'
        % feconf.TOPIC_VIEWER_URL_PREFIX,
        review_tests.ReviewTestsPage),
    get_redirect_route(
        r'%s/<classroom_url_fragment>/<topic_url_fragment>'
        r'/<story_url_fragment>' % feconf.STORY_DATA_HANDLER,
        story_viewer.StoryPageDataHandler),
    get_redirect_route(
        r'%s/<story_url_fragment>' % feconf.STORY_URL_FRAGMENT_HANDLER,
        story_editor.StoryUrlFragmentHandler),
    get_redirect_route(
        r'%s/<topic_name>' % feconf.TOPIC_NAME_HANDLER,
        topic_editor.TopicNameHandler),
    get_redirect_route(
        r'%s/<topic_url_fragment>' % feconf.TOPIC_URL_FRAGMENT_HANDLER,
        topic_editor.TopicUrlFragmentHandler),
    get_redirect_route(
        r'%s/<skill_description>' % feconf.SKILL_DESCRIPTION_HANDLER,
        skill_editor.SkillDescriptionHandler),
    get_redirect_route(
        r'%s/story' % feconf.TOPIC_VIEWER_URL_PREFIX,
        topic_viewer.TopicViewerPage),
    get_redirect_route(
        r'%s/story/<story_url_fragment>' % feconf.TOPIC_VIEWER_URL_PREFIX,
        story_viewer.StoryPage),
    get_redirect_route(
        r'%s/<classroom_url_fragment>/<topic_url_fragment>'
        r'/<story_url_fragment>/<node_id>' % feconf.STORY_PROGRESS_URL_PREFIX,
        story_viewer.StoryProgressHandler),
    get_redirect_route(
        r'%s/<classroom_url_fragment>/<topic_url_fragment>'
        r'/<subtopic_url_fragment>' % feconf.SUBTOPIC_DATA_HANDLER,
        subtopic_viewer.SubtopicPageDataHandler),
    get_redirect_route(
        r'%s/revision' % feconf.TOPIC_VIEWER_URL_PREFIX,
        topic_viewer.TopicViewerPage),
    get_redirect_route(
        r'%s/revision/<subtopic_url_fragment>' %
        feconf.TOPIC_VIEWER_URL_PREFIX, subtopic_viewer.SubtopicViewerPage),
    get_redirect_route(
        r'%s/<topic_id>' % feconf.TOPIC_EDITOR_STORY_URL,
        topic_editor.TopicEditorStoryHandler),
    get_redirect_route(
        r'%s' % feconf.TOPIC_VIEWER_URL_PREFIX,
        topic_viewer.TopicViewerPage),
    get_redirect_route(
        r'%s/practice' % feconf.TOPIC_VIEWER_URL_PREFIX,
        topic_viewer.TopicViewerPage),
    get_redirect_route(
        r'%s/<classroom_url_fragment>/<topic_url_fragment>'
        % feconf.TOPIC_DATA_HANDLER,
        topic_viewer.TopicPageDataHandler),
    get_redirect_route(
        r'%s/<classroom_url_fragment>' % feconf.CLASSROOM_DATA_HANDLER,
        classroom.ClassroomDataHandler),
    get_redirect_route(
        r'%s' % feconf.NEW_TOPIC_URL,
        topics_and_skills_dashboard.NewTopicHandler),
    get_redirect_route(
        r'%s' % feconf.UPLOAD_EXPLORATION_URL,
        creator_dashboard.UploadExplorationHandler),
    get_redirect_route(
        '/learner_dashboard',
        learner_dashboard.OldLearnerDashboardRedirectPage),
    get_redirect_route(
        r'%s' % feconf.LEARNER_DASHBOARD_URL,
        learner_dashboard.LearnerDashboardPage),
    get_redirect_route(
        r'%s' % feconf.LEARNER_DASHBOARD_DATA_URL,
        learner_dashboard.LearnerDashboardHandler),
    get_redirect_route(
        r'%s' % feconf.LEARNER_DASHBOARD_IDS_DATA_URL,
        learner_dashboard.LearnerDashboardIdsHandler),
    get_redirect_route(
        r'%s/<thread_id>' %
        feconf.LEARNER_DASHBOARD_FEEDBACK_THREAD_DATA_URL,
        learner_dashboard.LearnerDashboardFeedbackThreadHandler),
    get_redirect_route(
        r'%s' % feconf.TOPICS_AND_SKILLS_DASHBOARD_URL,
        topics_and_skills_dashboard.TopicsAndSkillsDashboardPage),
    get_redirect_route(
        r'%s' % feconf.MERGE_SKILLS_URL,
        topics_and_skills_dashboard.MergeSkillHandler),
    get_redirect_route(
        r'%s' % feconf.TOPICS_AND_SKILLS_DASHBOARD_DATA_URL,
        topics_and_skills_dashboard.TopicsAndSkillsDashboardPageDataHandler),
    get_redirect_route(
        r'%s/<skill_id>' % feconf.UNASSIGN_SKILL_DATA_HANDLER_URL,
        topics_and_skills_dashboard.TopicAssignmentsHandler),
    get_redirect_route(
        r'%s' % feconf.SKILL_DASHBOARD_DATA_URL,
        topics_and_skills_dashboard.SkillsDashboardPageDataHandler),

    get_redirect_route(
        r'%s/<activity_type>/<activity_id>' %
        feconf.LEARNER_INCOMPLETE_ACTIVITY_DATA_URL,
        reader.LearnerIncompleteActivityHandler),

    get_redirect_route(
        r'%s/<activity_type>/<activity_id>' % feconf.LEARNER_PLAYLIST_DATA_URL,
        learner_playlist.LearnerPlaylistHandler),

    get_redirect_route(
        r'/assetsdevhandler/<page_context>/<page_identifier>/'
        'assets/<asset_type:(image|audio|thumbnail)>/<encoded_filename>',
        resources.AssetDevHandler),
    get_redirect_route(
        r'/value_generator_handler/<generator_id>',
        resources.ValueGeneratorHandler),
    get_redirect_route(r'/promo_bar_handler', resources.PromoBarHandler),
    get_redirect_route(
        r'%s' % feconf.CUSTOM_PARENTS_LANDING_PAGE_URL,
        custom_landing_pages.StewardsLandingPage),
    get_redirect_route(
        r'%s' % feconf.CUSTOM_PARTNERS_LANDING_PAGE_URL,
        custom_landing_pages.StewardsLandingPage),
    get_redirect_route(
        r'%s' % feconf.CUSTOM_NONPROFITS_LANDING_PAGE_URL,
        custom_landing_pages.StewardsLandingPage),
    get_redirect_route(
        r'%s' % feconf.CUSTOM_TEACHERS_LANDING_PAGE_URL,
        custom_landing_pages.StewardsLandingPage),
    get_redirect_route(
        r'%s' % feconf.CUSTOM_VOLUNTEERS_LANDING_PAGE_URL,
        custom_landing_pages.StewardsLandingPage),

    get_redirect_route('/library', library.OldLibraryRedirectPage),
    get_redirect_route(
        r'%s' % feconf.LIBRARY_INDEX_URL, library.LibraryPage),
    get_redirect_route(
        r'%s' % feconf.LIBRARY_INDEX_DATA_URL, library.LibraryIndexHandler),
    get_redirect_route(
        r'%s' % feconf.LIBRARY_RECENTLY_PUBLISHED_URL,
        library.LibraryGroupPage),
    get_redirect_route(
        r'%s' % feconf.LIBRARY_TOP_RATED_URL, library.LibraryGroupPage),
    get_redirect_route(
        r'%s' % feconf.LIBRARY_GROUP_DATA_URL,
        library.LibraryGroupIndexHandler),
    get_redirect_route(r'%s' % feconf.LIBRARY_SEARCH_URL, library.LibraryPage),
    get_redirect_route(
        r'%s' % feconf.LIBRARY_SEARCH_DATA_URL, library.SearchHandler),
    get_redirect_route(r'/gallery', library.LibraryRedirectPage),
    get_redirect_route(r'/contribute', library.LibraryRedirectPage),
    get_redirect_route(r'/learn', classroom.DefaultClassroomRedirectPage),
    get_redirect_route(r'/playtest', library.LibraryRedirectPage),
    get_redirect_route(
        feconf.EXPLORATION_SUMMARIES_DATA_URL,
        library.ExplorationSummariesHandler),
    get_redirect_route(
        feconf.COLLECTION_SUMMARIES_DATA_URL,
        library.CollectionSummariesHandler),

    get_redirect_route(r'/profile/<username>', profile.ProfilePage),
    get_redirect_route(
        r'/profilehandler/data/<username>', profile.ProfileHandler),
    get_redirect_route(feconf.PREFERENCES_URL, profile.PreferencesPage),
    get_redirect_route(
        feconf.PREFERENCES_DATA_URL, profile.PreferencesHandler),
    get_redirect_route(
        r'/preferenceshandler/profile_picture', profile.ProfilePictureHandler),
    get_redirect_route(
        r'/preferenceshandler/profile_picture_by_username/<username>',
        profile.ProfilePictureHandlerByUsernameHandler),
    get_redirect_route(r'%s' % feconf.SIGNUP_URL, profile.SignupPage),
    get_redirect_route(r'%s' % feconf.SIGNUP_DATA_URL, profile.SignupHandler),
    get_redirect_route(feconf.DELETE_ACCOUNT_URL, profile.DeleteAccountPage),
    get_redirect_route(
        feconf.DELETE_ACCOUNT_HANDLER_URL, profile.DeleteAccountHandler),
    get_redirect_route(
        feconf.EXPORT_ACCOUNT_HANDLER_URL, profile.ExportAccountHandler),
    get_redirect_route(
        feconf.PENDING_ACCOUNT_DELETION_URL,
        profile.PendingAccountDeletionPage),
    get_redirect_route(
        r'%s' % feconf.USERNAME_CHECK_DATA_URL, profile.UsernameCheckHandler),
    get_redirect_route(
        r'%s' % feconf.SITE_LANGUAGE_DATA_URL, profile.SiteLanguageHandler),
    get_redirect_route(r'/userinfohandler', profile.UserInfoHandler),
    get_redirect_route(r'/url_handler', profile.UrlHandler),
    get_redirect_route(r'/moderator', moderator.ModeratorPage),
    get_redirect_route(
        r'/moderatorhandler/featured', moderator.FeaturedActivitiesHandler),
    get_redirect_route(
        r'/moderatorhandler/email_draft', moderator.EmailDraftHandler),

    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_URL_PREFIX,
        reader.ExplorationPage),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_URL_EMBED_PREFIX,
        reader.ExplorationEmbedPage),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_INIT_URL_PREFIX,
        reader.ExplorationHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_PRETESTS_URL_PREFIX,
        reader.PretestHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_FEATURES_PREFIX,
        features.ExplorationFeaturesHandler),
    get_redirect_route(
        '/explorehandler/exploration_start_event/<exploration_id>',
        reader.ExplorationStartEventHandler),
    get_redirect_route(
        '/explorehandler/exploration_actual_start_event/<exploration_id>',
        reader.ExplorationActualStartEventHandler),
    get_redirect_route(
        '/explorehandler/solution_hit_event/<exploration_id>',
        reader.SolutionHitEventHandler),
    get_redirect_route(
        r'/explorehandler/state_hit_event/<exploration_id>',
        reader.StateHitEventHandler),
    get_redirect_route(
        r'/explorehandler/state_complete_event/<exploration_id>',
        reader.StateCompleteEventHandler),
    get_redirect_route(
        r'/explorehandler/leave_for_refresher_exp_event/<exploration_id>',
        reader.LeaveForRefresherExpEventHandler),
    get_redirect_route(
        r'/explorehandler/answer_submitted_event/<exploration_id>',
        reader.AnswerSubmittedEventHandler),
    get_redirect_route(
        r'/explorehandler/give_feedback/<exploration_id>',
        reader.ReaderFeedbackHandler),
    get_redirect_route(
        r'/explorehandler/exploration_complete_event/<exploration_id>',
        reader.ExplorationCompleteEventHandler),
    get_redirect_route(
        r'/explorehandler/exploration_maybe_leave_event/<exploration_id>',
        reader.ExplorationMaybeLeaveHandler),
    get_redirect_route(
        r'/explorehandler/stats_events/<exploration_id>',
        reader.StatsEventsHandler),
    get_redirect_route(
        r'/explorehandler/store_playthrough/<exploration_id>',
        reader.StorePlaythroughHandler),
    get_redirect_route(
        r'/explorehandler/rating/<exploration_id>', reader.RatingHandler),
    get_redirect_route(
        r'/explorehandler/recommendations/<exploration_id>',
        reader.RecommendationsHandler),
    get_redirect_route(
        r'%s/<entity_type>/<entity_id>' % (
            feconf.LEARNER_ANSWER_DETAILS_SUBMIT_URL),
        reader.LearnerAnswerDetailsSubmissionHandler),

    get_redirect_route(
        r'%s/<question_id>' % feconf.QUESTION_EDITOR_DATA_URL_PREFIX,
        question_editor.EditableQuestionDataHandler),

    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EDITOR_URL_PREFIX,
        editor.ExplorationPage),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_DATA_PREFIX,
        editor.ExplorationHandler),
    get_redirect_route(
        r'/createhandler/download/<exploration_id>',
        editor.ExplorationFileDownloader),
    get_redirect_route(
        r'/createhandler/imageupload/<entity_type>/<entity_id>',
        editor.ImageUploadHandler),
    get_redirect_route(
        r'/createhandler/audioupload/<exploration_id>',
        voice_artist.AudioUploadHandler),
    get_redirect_route(
        r'/createhandler/state_yaml/<exploration_id>',
        editor.StateYamlHandler),
    get_redirect_route(
        r'/createhandler/revert/<exploration_id>',
        editor.ExplorationRevertHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_RIGHTS_PREFIX,
        editor.ExplorationRightsHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.USER_PERMISSIONS_URL_PREFIX,
        editor.UserExplorationPermissionsHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_STATUS_PREFIX,
        editor.ExplorationStatusHandler),
    get_redirect_route(
        r'/createhandler/moderatorrights/<exploration_id>',
        editor.ExplorationModeratorRightsHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.USER_EXPLORATION_EMAILS_PREFIX,
        editor.UserExplorationEmailsHandler),
    get_redirect_route(
        r'/createhandler/snapshots/<exploration_id>',
        editor.ExplorationSnapshotsHandler),
    get_redirect_route(
        r'/createhandler/statistics/<exploration_id>',
        editor.ExplorationStatisticsHandler),
    get_redirect_route(
        r'/createhandler/state_interaction_stats/<exploration_id>/<escaped_state_name>',  # pylint: disable=line-too-long
        editor.StateInteractionStatsHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.EXPLORATION_STATE_ANSWER_STATS_PREFIX,
        editor.StateAnswerStatisticsHandler),
    get_redirect_route(
        r'/createhandler/started_tutorial_event/<exploration_id>',
        editor.StartedTutorialEventHandler),
    get_redirect_route(
        r'/createhandler/started_translation_tutorial_event/<exploration_id>',
        voice_artist.StartedTranslationTutorialEventHandler),
    get_redirect_route(
        r'/createhandler/autosave_draft/<exploration_id>',
        editor.EditorAutosaveHandler),
    get_redirect_route(
        r'/createhandler/get_top_unresolved_answers/<exploration_id>',
        editor.TopUnresolvedAnswersHandler),
    get_redirect_route(
        r'%s/<entity_type>/<entity_id>' %
        feconf.LEARNER_ANSWER_INFO_HANDLER_URL,
        editor.LearnerAnswerInfoHandler),

    get_redirect_route(
        r'%s' % feconf.RECENT_COMMITS_DATA_URL,
        recent_commits.RecentCommitsHandler),
    get_redirect_route(
        r'%s' % feconf.RECENT_FEEDBACK_MESSAGES_DATA_URL,
        feedback.RecentFeedbackMessagesHandler),

    get_redirect_route(
        r'%s/<thread_id>' % feconf.FEEDBACK_THREAD_VIEW_EVENT_URL,
        feedback.FeedbackThreadViewEventHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.FEEDBACK_THREADLIST_URL_PREFIX,
        feedback.ThreadListHandler),
    get_redirect_route(
        r'%s/<topic_id>' % feconf.FEEDBACK_THREADLIST_URL_PREFIX_FOR_TOPICS,
        feedback.ThreadListHandlerForTopicsHandler),
    get_redirect_route(
        r'%s/<thread_id>' % feconf.FEEDBACK_THREAD_URL_PREFIX,
        feedback.ThreadHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.FEEDBACK_STATS_URL_PREFIX,
        feedback.FeedbackStatsHandler),
    get_redirect_route(
        r'%s/' % feconf.SUGGESTION_URL_PREFIX,
        suggestion.SuggestionHandler),
    get_redirect_route(
        r'%s/<suggestion_id>' % feconf.UPDATE_TRANSLATION_SUGGESTION_URL_PREFIX,
        suggestion.UpdateTranslationSuggestionHandler),
    get_redirect_route(
        r'%s/<suggestion_id>' % feconf.UPDATE_QUESTION_SUGGESTION_URL_PREFIX,
        suggestion.UpdateQuestionSuggestionHandler),
    get_redirect_route(
        r'%s' % feconf.QUESTIONS_URL_PREFIX,
        reader.QuestionPlayerHandler),
    get_redirect_route(
        r'%s/exploration/<target_id>/<suggestion_id>' %
        feconf.SUGGESTION_ACTION_URL_PREFIX,
        suggestion.SuggestionToExplorationActionHandler),
    get_redirect_route(
        r'%s/resubmit/<suggestion_id>' % feconf.SUGGESTION_ACTION_URL_PREFIX,
        suggestion.ResubmitSuggestionHandler),
    get_redirect_route(
        r'%s/skill/<target_id>/<suggestion_id>' %
        feconf.SUGGESTION_ACTION_URL_PREFIX,
        suggestion.SuggestionToSkillActionHandler),
    get_redirect_route(
        r'%s' % feconf.SUGGESTION_LIST_URL_PREFIX,
        suggestion.SuggestionListHandler),
    get_redirect_route(
        r'/getreviewablesuggestions/<target_type>/<suggestion_type>',
        suggestion.ReviewableSuggestionsHandler),
    get_redirect_route(
        r'/getsubmittedsuggestions/<target_type>/<suggestion_type>',
        suggestion.UserSubmittedSuggestionsHandler),
    get_redirect_route(
        r'%s' % feconf.SUBSCRIBE_URL_PREFIX,
        subscriptions.SubscribeHandler),
    get_redirect_route(
        r'%s' % feconf.UNSUBSCRIBE_URL_PREFIX,
        subscriptions.UnsubscribeHandler),
    get_redirect_route(
        r'%s/<exploration_id>' % feconf.FLAG_EXPLORATION_URL_PREFIX,
        reader.FlagExplorationHandler),
    get_redirect_route(
        r'%s/<collection_id>' % feconf.COLLECTION_URL_PREFIX,
        collection_viewer.CollectionPage),
    get_redirect_route(
        r'%s/<collection_id>' % feconf.COLLECTION_DATA_URL_PREFIX,
        collection_viewer.CollectionDataHandler),

    get_redirect_route(
        r'%s/<collection_id>' % feconf.COLLECTION_EDITOR_URL_PREFIX,
        collection_editor.CollectionEditorPage),
    get_redirect_route(
        r'%s/<collection_id>' % feconf.COLLECTION_EDITOR_DATA_URL_PREFIX,
        collection_editor.EditableCollectionDataHandler),
    get_redirect_route(
        r'%s/<collection_id>' % feconf.COLLECTION_RIGHTS_PREFIX,
        collection_editor.CollectionRightsHandler),
    get_redirect_route(
        r'%s/<collection_id>' % feconf.COLLECTION_PUBLISH_PREFIX,
        collection_editor.CollectionPublishHandler),
    get_redirect_route(
        r'%s/<collection_id>' % feconf.COLLECTION_UNPUBLISH_PREFIX,
        collection_editor.CollectionUnpublishHandler),

    get_redirect_route(
        r'%s/<topic_id>' % feconf.TOPIC_EDITOR_URL_PREFIX,
        topic_editor.TopicEditorPage),
    get_redirect_route(
        r'%s/<topic_id>' % feconf.TOPIC_EDITOR_DATA_URL_PREFIX,
        topic_editor.EditableTopicDataHandler),
    get_redirect_route(
        r'%s/<topic_id>/<subtopic_id>' %
        feconf.SUBTOPIC_PAGE_EDITOR_DATA_URL_PREFIX,
        topic_editor.EditableSubtopicPageDataHandler),
    get_redirect_route(
        r'%s/<topic_id>' % feconf.TOPIC_RIGHTS_URL_PREFIX,
        topic_editor.TopicRightsHandler),
    get_redirect_route(
        r'%s/<topic_id>' % feconf.TOPIC_STATUS_URL_PREFIX,
        topic_editor.TopicPublishHandler),
    get_redirect_route(
        r'%s/<topic_id>' % feconf.TOPIC_SEND_MAIL_URL_PREFIX,
        topic_editor.TopicPublishSendMailHandler),

    get_redirect_route(
        r'%s/<comma_separated_skill_ids>' % feconf.CONCEPT_CARD_DATA_URL_PREFIX,
        concept_card_viewer.ConceptCardDataHandler),
    get_redirect_route(
        r'%s/<question_id>' % feconf.QUESTION_SKILL_LINK_URL_PREFIX,
        question_editor.QuestionSkillLinkHandler),
    get_redirect_route(
        r'%s/<comma_separated_skill_ids>' % feconf.SKILL_DATA_URL_PREFIX,
        skill_editor.SkillDataHandler),
    get_redirect_route(
        r'%s' % feconf.FETCH_SKILLS_URL_PREFIX,
        skill_editor.FetchSkillsHandler),
    get_redirect_route(
        r'%s/<skill_id>' % feconf.SKILL_EDITOR_URL_PREFIX,
        skill_editor.SkillEditorPage),
    get_redirect_route(
        r'%s/<skill_id>' % feconf.SKILL_EDITOR_DATA_URL_PREFIX,
        skill_editor.EditableSkillDataHandler),
    get_redirect_route(
        r'%s' % feconf.SKILL_MASTERY_DATA_URL,
        skill_mastery.SkillMasteryDataHandler),
    get_redirect_route(
        r'%s/<skill_id>' % feconf.SKILL_RIGHTS_URL_PREFIX,
        skill_editor.SkillRightsHandler),

    get_redirect_route(
        r'%s/<story_id>' % feconf.STORY_EDITOR_URL_PREFIX,
        story_editor.StoryEditorPage),
    get_redirect_route(
        r'%s/<story_id>' % feconf.STORY_EDITOR_DATA_URL_PREFIX,
        story_editor.EditableStoryDataHandler),
    get_redirect_route(
        r'%s/<story_id>' % feconf.STORY_PUBLISH_HANDLER,
        story_editor.StoryPublishHandler),
    get_redirect_route(
        r'%s/<story_id>' %
        feconf.VALIDATE_STORY_EXPLORATIONS_URL_PREFIX,
        story_editor.ValidateExplorationsHandler),

    get_redirect_route(
        '/classroom_promos_status_handler',
        classroom.ClassroomPromosStatusHandler),

    get_redirect_route(r'/emaildashboard', email_dashboard.EmailDashboardPage),
    get_redirect_route(
        r'/emaildashboarddatahandler',
        email_dashboard.EmailDashboardDataHandler),
    get_redirect_route(
        r'/querystatuscheck', email_dashboard.QueryStatusCheckHandler),
    get_redirect_route(
        r'/emaildashboardresult/<query_id>',
        email_dashboard.EmailDashboardResultPage),
    get_redirect_route(
        r'/emaildashboardcancelresult/<query_id>',
        email_dashboard.EmailDashboardCancelEmailHandler),
    get_redirect_route(
        r'/emaildashboardtestbulkemailhandler/<query_id>',
        email_dashboard.EmailDashboardTestBulkEmailHandler),
    get_redirect_route(
        r'%s' % feconf.EXPLORATION_METADATA_SEARCH_URL,
        collection_editor.ExplorationMetadataSearchHandler),
    get_redirect_route(
        r'/explorationdataextractionhandler', admin.DataExtractionQueryHandler),
    get_redirect_route(
        r'/senddummymailtoadminhandler', admin.SendDummyMailToAdminHandler),
    get_redirect_route(r'/updateusernamehandler', admin.UpdateUsernameHandler),
    get_redirect_route(
        r'/numberofdeletionrequestshandler',
        admin.NumberOfDeletionRequestsHandler),
    get_redirect_route(
        r'/verifyusermodelsdeletedhandler',
        admin.VerifyUserModelsDeletedHandler),
    get_redirect_route(r'/deleteuserhandler', admin.DeleteUserHandler),
    get_redirect_route(r'/frontend_errors', FrontendErrorHandler),

    get_redirect_route(r'/session_begin', base.SessionBeginHandler),
    get_redirect_route(r'/session_end', base.SessionEndHandler),

    get_redirect_route(
        r'%s/%s/<exploration_id>' % (
            feconf.IMPROVEMENTS_URL_PREFIX,
            constants.TASK_ENTITY_TYPE_EXPLORATION),
        improvements.ExplorationImprovementsHandler),
    get_redirect_route(
        r'%s/%s/<exploration_id>' % (
            feconf.IMPROVEMENTS_HISTORY_URL_PREFIX,
            constants.TASK_ENTITY_TYPE_EXPLORATION),
        improvements.ExplorationImprovementsHistoryHandler),
    get_redirect_route(
        r'%s/%s/<exploration_id>' % (
            feconf.IMPROVEMENTS_CONFIG_URL_PREFIX,
            constants.TASK_ENTITY_TYPE_EXPLORATION),
        improvements.ExplorationImprovementsConfigHandler),

    get_redirect_route(
        r'/issuesdatahandler/<exploration_id>', editor.FetchIssuesHandler),

    get_redirect_route(
        r'/ml/trainedclassifierhandler', classifier.TrainedClassifierHandler),
    get_redirect_route(
        r'/ml/nextjobhandler', classifier.NextJobHandler),

    get_redirect_route(
        r'/playthroughdatahandler/<exploration_id>/<playthrough_id>',
        editor.FetchPlaythroughHandler),

    get_redirect_route(
        r'/resolveissuehandler/<exploration_id>', editor.ResolveIssueHandler),

    get_redirect_route(
        r'%s' % feconf.CSRF_HANDLER_URL, base.CsrfTokenHandler),

    get_redirect_route(
        r'/platform_features_evaluation_handler',
        platform_feature.PlatformFeaturesEvaluationHandler),
    get_redirect_route(
        r'/platform_feature_dummy_handler',
        platform_feature.PlatformFeatureDummyHandler),

    get_redirect_route(
        r'/learn/<classroom_url_fragment>', classroom.ClassroomPage),
]

# Adding redirects for topic landing pages.
for subject in feconf.AVAILABLE_LANDING_PAGES:
    for topic in feconf.AVAILABLE_LANDING_PAGES[subject]:
        URLS.append(
            get_redirect_route(
                r'/%s/%s' % (subject, topic),
                custom_landing_pages.TopicLandingPage))

# 404 error handler (Needs to be at the end of the URLS list).
URLS.append(get_redirect_route(r'/<:.*>', base.Error404Handler))

app = transaction_services.toplevel_wrapper(  # pylint: disable=invalid-name
    webapp2.WSGIApplication(URLS, debug=feconf.DEBUG))

firebase_auth_services.establish_firebase_connection()