old_contents: """
  Flask server app.
  """
  
  import datetime as dt
  import sys
  import flask
  import sqlalchemy as sa
  import coils
  import tables
  import mapping
  
  app = flask.Flask(__name__)
  
  # Load configuration file.
  CONFIG = sys.argv[1] if len(sys.argv)>=2 else 'wabbit.cfg'
  config = coils.Config(CONFIG)
  
  @app.route('/')
  def index():
      """Render the index page."""
      return flask.render_template('index.html')    
  
  @app.route('/info')
  def info():
      """Return JSON of server info."""
      # Connect to database engine.
      engine = sa.create_engine(
          'mysql://{}:{}@{}/{}'.format(
              config['username'], config['password'],
              config['host'], config['db_name']))
      Session = sa.orm.sessionmaker(bind=engine)
      session = Session()
      now = dt.datetime.now()
      datum = session.query(mapping.Datum).\
          filter(mapping.Datum.name=='size')[0]
      return flask.jsonify(server_time=now, db_size=datum.value)
  
  if __name__ == '__main__':
      app.run()
  
new_contents: """
  Flask server app.
  """
  
  import datetime as dt
  import sys
  import flask
  from flask.ext.sqlalchemy import SQLAlchemy
  import coils
  import mapping
  
  # Load configuration file.
  CONFIG = sys.argv[1] if len(sys.argv)>=2 else 'wabbit.cfg'
  config = coils.Config(CONFIG)
  
  # Initialize Flask and SQLAlchemy.
  app = flask.Flask(__name__)
  app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://{}:{}@{}/{}'.format(
      config['username'], config['password'],
      config['host'], config['db_name'])
  db = SQLAlchemy(app)
  
  @app.route('/')
  def index():
      """Render the index page."""
      return flask.render_template('index.html')    
  
  @app.route('/info')
  def info():
      """Return JSON of server info."""
      now = dt.datetime.now()
      datum = db.session.query(mapping.Datum).\
          filter(mapping.Datum.name=='size')[0]
      return flask.jsonify(server_time=now, db_size=datum.value)
  
  if __name__ == '__main__':
      app.run()
  
subject: Use SQLAlchemy extension in Flask app.