text: import logging
  from logging.handlers import SMTPHandler, RotatingFileHandler
  import os
  from flask import Flask, request, current_app
  from flask_sqlalchemy import SQLAlchemy
  from flask_migrate import Migrate
  from flask_login import LoginManager
  from flask_mail import Mail
  from flask_bootstrap import Bootstrap
  from flask_moment import Moment
  from flask_babel import Babel, lazy_gettext as _l
  from config import Config
  from elasticsearch import Elasticsearch
  
  db = SQLAlchemy()
  migrate = Migrate()
  login = LoginManager()
  login.login_view = 'auth.login'
  login.login_message = _l('Please log in to access this page.')
  mail = Mail()
  bootstrap = Bootstrap()
  moment = Moment()
  babel = Babel()
  
  
  def create_app(config_class=Config):
      app = Flask(__name__)
      app.config.from_object(config_class)
  
      db.init_app(app)
      migrate.init_app(app, db)
      login.init_app(app)
      mail.init_app(app)
      bootstrap.init_app(app)
      moment.init_app(app)
      babel.init_app(app)
  
      app.elasticsearch = Elasticsearch([app.config['ELASTICSEARCH_URL']]) \
          if app.config['ELASTICSEARCH_URL'] else None
  
      from app.errors import bp as errors_bp
      app.register_blueprint(errors_bp)
  
      from app.auth import bp as auth_bp
      app.register_blueprint(auth_bp, url_prefix='/auth')
  
      from app.main import bp as main_bp
      app.register_blueprint(main_bp)
  
      from app.feedback import bp as fb_bp
      app.register_blueprint(fb_bp)
  
      if not app.debug and not app.testing:
          if app.config['MAIL_SERVER']:
              auth = None
              if app.config['MAIL_USERNAME'] or app.config['MAIL_PASSWORD']:
                  auth = (app.config['MAIL_USERNAME'],
                          app.config['MAIL_PASSWORD'])
              secure = None
              if app.config['MAIL_USE_TLS']:
                  secure = ()
              mail_handler = SMTPHandler(
                  mailhost=(app.config['MAIL_SERVER'], app.config['MAIL_PORT']),
                  fromaddr='no-reply@' + app.config['MAIL_SERVER'],
                  toaddrs=app.config['ADMINS'], subject='Microblog Failure',
                  credentials=auth, secure=secure)
              mail_handler.setLevel(logging.ERROR)
              app.logger.addHandler(mail_handler)
  
          if not os.path.exists('logs'):
              os.mkdir('logs')
          file_handler = RotatingFileHandler('logs/microblog.log',
                                             maxBytes=10240, backupCount=10)
          file_handler.setFormatter(logging.Formatter(
              '%(asctime)s %(levelname)s: %(message)s '
              '[in %(pathname)s:%(lineno)d]'))
          file_handler.setLevel(logging.INFO)
          app.logger.addHandler(file_handler)
  
          app.logger.setLevel(logging.INFO)
          app.logger.info('Microblog startup')
  
      return app
  
  
  @babel.localeselector
  def get_locale():
      return request.accept_languages.best_match(current_app.config['LANGUAGES'])
  
  
  from app import models
  