Create API on AWS Lambda

Lambda script

Lambda could collect POST body and URL params using event. For POST body, params could be extracted directly like event['param1']. As of September 2017, you no longer have to configure mappings to access the request body. All you need to do is check, “Use Lambda Proxy integration”, under Integration Request, under the resource of AWS API Gateway.

You’ll then be able to access query parameters, path parameters and headers like so

event['pathParameters']['param1']
event["queryStringParameters"]['queryparam1']
event['requestContext']['identity']['userAgent']
event['requestContext']['identity']['sourceIP']

For proxied API, the handler function should return the response in the following format:

{
    "isBase64Encoded": true|false,
    "statusCode": httpStatusCode,
    "headers": { "headerName": "headerValue", ... },
    "body": "..."
}

Usually, when you see “Malformed Lambda proxy response”, it means your response from your Lambda function doesn’t match the format API Gateway is expecting.