如何从 AWS lambda 上的 API 获得正确响应

Question

This is my first time soliciting the Stack-Overflow community. Since a few days I have been learning to use the AWS lambda service connected with GETEWAY. I need to do a GET on an API but the problem is that I constantly receive a empty response.

Here is an example of my code with a free access API:

var getApi= async function(event) {
        var x =  await axios.get(url)       
}


var getResponse = async function(){
  var data= await getApi()
  if (data.status ==200){
       return data
  }

}



exports.handler = async function() {


    return getResponse().then(res => {
        const response = {
            statusCode: 200,
            body: JSON.stringify(res), 
        };
        return response

    }).catch(error => { return error})
};

Thank you very much for your help,

Answer 1

I would suggest using console.log() all over the file to debug. You should by default be able to see the response to these console logs in Cloudwatch:)

Read more here:

https://docs.aws.amazon.com/lambda/latest/dg/monitoring-functions-logs.html

Answer 2

I myself ran into this issue very recently. The solution is:

1. If you are using the Lambda as an authorizer in your AWS Gateway, then the Lambda should return a JSON object that contains principalId, policyDocument and context.
2. Context is a map where you can add your own custom variables such as Strings, Numbers and Booleans.

The entire content of the JSON object will be returned to the Gateway. Check out this documentation: https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-lambda-authorizer-output.html

I also have a pretty detailed Stackoverflow post on how the Gateway should be configured via Cloudformation YAML file: AWS API Gateway with Lambda Authorizer

Answer 3

It is because of node.js asynchronous call. Your function finishes the running before asynchronous call returns. I fixed some lines of codes. I wish this might be helpful for you.

const getApi= async function() {
   return await axios.get(url)
}

const getResponse = async function(){
    const data= await getApi()
    if (data.status ==200){
        return data
    }
}

exports.handler = async function() {
    return await getResponse().then(res => {
        const response = {
            statusCode: 200,
            body: JSON.stringify(res), 
        }
        return response
    }).catch(error => console.error(error))
}