Configuring API Gateway for CORS
Explore how to configure Cross-Origin Resource Sharing in API Gateway to enable secure web API access for serverless applications. Understand setting up OPTIONS handlers, managing CORS headers with environment variables, and using AWS SAM to simplify configuration. This lesson prepares you to handle pre-flight requests and properly manage API responses for serverless workflows.
We'll cover the following...
OPTIONS handler
The CORS request going from the web page to your API is going to be a bit more tricky. You’ll need to add an OPTIONS handler to the API and also change the response in your function to include the correct origin.
There are two ways of configuring OPTIONS handlers. The first is to add a Lambda function and an API endpoint. This would make it fully flexible, so you could dynamically calculate the right origin and response headers, but it would add an API call and a Lambda execution to your costs. In ...