Book Image

Building Serverless Python Web Services with Zappa

By : Abdulwahid Abdulhaque Barguzar
Book Image

Building Serverless Python Web Services with Zappa

By: Abdulwahid Abdulhaque Barguzar

Overview of this book

Serverless applications are becoming very popular these days, not just because they save developers the trouble of managing the servers, but also because they provide several other benefits such as cutting heavy costs and improving the overall performance of the application. This book will help you build serverless applications in a quick and efficient way. We begin with an introduction to AWS and the API gateway, the environment for serverless development, and Zappa. We then look at building, testing, and deploying apps in AWS with three different frameworks--Flask, Django, and Pyramid. Setting up a custom domain along with SSL certificates and configuring them with Zappa is also covered. A few advanced Zappa settings are also covered along with securing Zappa with AWS VPC. By the end of the book you will have mastered using three frameworks to build robust and cost-efficient serverless apps in Python.
Table of Contents (20 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Enabling CORS


Cross-Origin Resource Sharing (CORS) is an essential part of serving the API over the same domain or a different hosted domain. The AWS API Gateway provides a feature to enable CORS functionality. Once you have configured an API resource on an API Gateway, you must enable CORS using the API Gateway web console. Enabling CORS over API Gateway resources requires that you set the OPTION method with some response headers, such as the following:

  • Access-Control-Allow-Methods
  • Access-Control-Allow-Headers
  • Access-Control-Allow-Origin

You can take a look at the manual process of configuring CORS in the API Gateway in AWS's official documentation (https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-cors.html). 

Zappa automates the process of configuring CORS with API Gateway resources by using a setting attribute called cors, as mentioned in the following code snippet:

{
    "dev": {
             ...
             "cors": true/false
             ...
     }
}

Zappa sets the default...