old_contents: import os
  
  from flask import Flask
  from flask_restful import Api
  from dns.resolver import Resolver
  from flask_cors import CORS
  
  
  dns_resolver = Resolver()
  
  
  def create_app(config_name):
      app = Flask(__name__)
      if config_name == 'dev':
          app.config.from_object('resolverapi.config.DevelopmentConfig')
      else:
          app.config.from_object('resolverapi.config.BaseConfig')
  
      # Get nameservers from environment variable or default to OpenDNS resolvers
      if os.environ.get('RESOLVERS'):
          app.config['RESOLVERS'] = [addr.strip() for addr in os.environ.get('RESOLVERS').split(',')]
      # Respond with Access-Control-Allow-Origin headers. Use * to accept all
      if os.environ.get('CORS_ORIGIN'):
          CORS(app, origins=os.environ.get('CORS_ORIGIN'))
  
      dns_resolver.lifetime = 3.0
  
      from resolverapi.endpoints import ReverseLookup
      from resolverapi.endpoints import LookupRecordType
      api = Api(app)
      api.add_resource(ReverseLookup, '/reverse/<ip>')
      api.add_resource(LookupRecordType, '/<rdtype>/<domain>')
  
      @app.route('/')
      def root():
          """Health check. No data returned. Just 200."""
          return '', 200
  
      return app
  
new_contents: import os
  
  from flask import Flask, jsonify
  from flask_restful import Api
  from dns.resolver import Resolver
  from flask_cors import CORS
  
  
  dns_resolver = Resolver()
  
  
  def create_app(config_name):
      app = Flask(__name__)
      if config_name == 'dev':
          app.config.from_object('resolverapi.config.DevelopmentConfig')
      else:
          app.config.from_object('resolverapi.config.BaseConfig')
  
      # Get nameservers from environment variable or default to OpenDNS resolvers
      if os.environ.get('RESOLVERS'):
          app.config['RESOLVERS'] = [addr.strip() for addr in os.environ.get('RESOLVERS').split(',')]
      # Respond with Access-Control-Allow-Origin headers. Use * to accept all
      if os.environ.get('CORS_ORIGIN'):
          CORS(app, origins=os.environ.get('CORS_ORIGIN'))
  
      dns_resolver.lifetime = 3.0
  
      from resolverapi.endpoints import ReverseLookup
      from resolverapi.endpoints import LookupRecordType
      api = Api(app)
      api.add_resource(ReverseLookup, '/reverse/<ip>')
      api.add_resource(LookupRecordType, '/<rdtype>/<domain>')
  
      @app.route('/')
      def root():
          """Provide user a link to the main page. Also this route acts as a health check, returns 200."""
          return jsonify({'message': "Check out www.openresolve.com for usage."}), 200
  
      return app
  
subject: Create root page for api.openresolve.com