AWS Error: Proxy integrations cannot be configured to transform responses

Question

I'm a beginner in Amazon's Lambda-API implementations.

I'm just deploying a very simple API: a very simple lambda function with Python 2.7 printing "Hello World" that I trigger with API Gateway. However, when I click on the Invoke URL link, it tells me "{"message": "Internal server error"}".

Thus, I'm trying to see what is wrong here, so I click on the API itself and I can see the following being grey in my Method Execution: "Integration Response: Proxy integrations cannot be configured to transform responses."

I have tested many different configurations but I still face the same error. I have no idea why this step is grey.

Answer 1

I had the same problem when trying to integrate API gateway and lambda function. Basically, after spending a couple of hours, I figure out. So when you were creating a new resource or method the Use Lambda Proxy integration was set by default.

So you need to remove this. Follow to Integration Request and untick the Use Lambda Proxy integration

you will see the following picture

Then in you Resources, Atction tab, choose Enable CORS

Once this done Deploy your API once again and test function. Also, this topic will explain what's happening under the hood.

Good luck...

Answer 2

The Lambda response should be in a specific format for API gateway to process. You could find details in the post. https://aws.amazon.com/premiumsupport/knowledge-center/malformed-502-api-gateway/

exports.handler = (event, context, callback) => {

var responseBody = {
    "key3": "value3",
    "key2": "value2",
    "key1": "value1"
};

var response = {
    "statusCode": 200,
    "headers": {
        "my_header": "my_value"
    },
    "body": JSON.stringify(responseBody),
    "isBase64Encoded": false
};
callback(null, response);