Enable CORS on AWS Lambda

There are few ways in which you can support CORS for your lambda function on AWS

• API Gateway
• Handle CORS inside lambda function

So what is CORS?

Browsers way to protect resources from being accessed from different domains.

In lay man , `abc.com` cannot access resources from `def.com` until def.com has CORS enabled

API Gateway

• Goto AWS management console , search for API Gateway
• Find the API gateway that triggers your Lambda function

• Select Enable Cors from actions . this should do the job for you.

Handle CORS using Lambda Function

Add ‘ Access-Control-Allow-Origin’: ‘*’ header to all response headers

example: handle OPTIONS request

// handle preflight request from all origins
      
if (event.httpMethod == 'OPTIONS') {
        return {
          statusCode: 200,
          headers: {
            'Access-Control-Allow-Headers': 'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token',
            'Access-Control-Allow-Origin': '*',
            'Access-Control-Allow-Credentials': 'true',
          },
          body: JSON.stringify({ message: 'Success' }),
          isBase64Encoded: false,
        };
      }body: JSON.stringify({ message: 'Success' }),
isBase64Encoded: false,
};
}

This is example reference you might need to adapt a bit according to your needs!!

Happy Coding !!