How do I pass arguments to AWS Lambda functions using GET requests?

Question

Say I want to pass val1 and val2 in the URL string when making a GET request from my Api gateway endpoint to my Lambda function:

https://xyz.execute-api.amazonaw         


        

Answer 1

All the information can be retrieved from event object.

For example : The value of a variable foo can be retrieved from the event as event["foo"].

Answer 2

After defining the query string parameters in Method Request section of the API Gateway, you then need to define a Mapping Template in the Method Execution section.

In the Method Execution section, select Mapping Templates and then click Add Mapping Template. Enter application/json for the Content Type and then create a mapping template that looks something like this:

{
    "va1": "$input.params('val1')",
    "val2": "$input.params('val2')"
}

This will tell API Gateway to take the input parameters (either passed on the path, or in headers, or in query parameters) called val1 and val2 and send them to the Lambda function in the event data as val1 and val2.