old_contents: import logging
  import operator
  from flask import (request, render_template, flash,
                     url_for, redirect, current_app)
  from flask_babel import gettext
  
  from conf import API_ROOT
  from web.controllers import FeedController
  from web.lib.view_utils import etag_match
  
  logger = logging.getLogger(__name__)
  
  
  @current_app.errorhandler(401)
  def authentication_required(error):
      if API_ROOT in request.url:
          return error
      flash(gettext('Authentication required.'), 'info')
      return redirect(url_for('login'))
  
  
  @current_app.errorhandler(403)
  def authentication_failed(error):
      if API_ROOT in request.url:
          return error
      flash(gettext('Forbidden.'), 'danger')
      return redirect(url_for('login'))
  
  
  @current_app.errorhandler(404)
  def page_not_found(error):
      return render_template('errors/404.html'), 404
  
  
  @current_app.errorhandler(500)
  def internal_server_error(error):
      return render_template('errors/500.html'), 500
  
  
  @current_app.errorhandler(AssertionError)
  def handle_sqlalchemy_assertion_error(error):
      return error.args[0], 400
  
  
  @current_app.route('/popular', methods=['GET'])
  @etag_match
  def popular():
      feeds = FeedController().count_by_link()
      sorted_feeds = sorted(feeds.items(), key=operator.itemgetter(1),
                              reverse=True)
      return render_template('popular.html', popular=sorted_feeds[:100])
  
  
  @current_app.route('/about', methods=['GET'])
  @etag_match
  def about():
      return render_template('about.html')
  
new_contents: import logging
  import operator
  from datetime import datetime, timedelta
  from flask import (request, render_template, flash,
                     url_for, redirect, current_app)
  from flask_babel import gettext
  from sqlalchemy import desc
  
  from conf import API_ROOT
  from web.controllers import FeedController
  from web.lib.view_utils import etag_match
  
  logger = logging.getLogger(__name__)
  
  
  @current_app.errorhandler(401)
  def authentication_required(error):
      if API_ROOT in request.url:
          return error
      flash(gettext('Authentication required.'), 'info')
      return redirect(url_for('login'))
  
  
  @current_app.errorhandler(403)
  def authentication_failed(error):
      if API_ROOT in request.url:
          return error
      flash(gettext('Forbidden.'), 'danger')
      return redirect(url_for('login'))
  
  
  @current_app.errorhandler(404)
  def page_not_found(error):
      return render_template('errors/404.html'), 404
  
  
  @current_app.errorhandler(500)
  def internal_server_error(error):
      return render_template('errors/500.html'), 500
  
  
  @current_app.errorhandler(AssertionError)
  def handle_sqlalchemy_assertion_error(error):
      return error.args[0], 400
  
  
  @current_app.route('/popular', methods=['GET'])
  @etag_match
  def popular():
      """
      Return the most popular feeds for the last 30 days.
      """
      last_added_feed = FeedController().read().\
                          order_by(desc('created_date')).limit(1)
      if last_added_feed:
          last_added_feed_date = last_added_feed.all()[0].created_date
      else:
          last_added_feed_date = datetime.now()
      not_before = last_added_feed_date - timedelta(days=30)
      filters = {}
      filters['created_date__gt'] = not_before
  
      feeds = FeedController().count_by_link(**filters)
      sorted_feeds = sorted(feeds.items(), key=operator.itemgetter(1),
                              reverse=True)
      return render_template('popular.html', popular=sorted_feeds[:100])
  
  
  @current_app.route('/about', methods=['GET'])
  @etag_match
  def about():
      return render_template('about.html')
  
subject: Return the most popular feeds for the last 30 days (before the date of the last added feed).