Postman AWS Rest API — as javascript?

Question

I made a simple IAM authenticated API that returns a random number. [GET only]
Postman call works ok:
https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-use-postman-to-call-api.html?shortFooter=true

What is a simple way of getting the postman call to plain javascript
(No npm or webpack)

Thanks heaps

Answer 1

You can use axios and aws4 library in javascript to make api calls and send a signed request respectively.You need to authenticate the user via Cognito and retrieve temporary credentials (access key, secret key, and session token)

let request = {
  host: 'myapi.execute-api.us-west-2.amazonaws.com',
  method: 'GET',
  url: 'https://myapi.execute-api.us-west-2.amazonaws.com/foo/bar',
  path: '/foo/bar'
}

let signedRequest = aws4.sign(request,
  {
    // assumes user has authenticated and we have called
    // AWS.config.credentials.get to retrieve keys and
    // session tokens
    secretAccessKey: AWS.config.credentials.secretAccessKey,
    accessKeyId: AWS.config.credentials.accessKeyId,
    sessionToken: AWS.config.credentials.sessionToken
  })

delete signedRequest.headers['Host']
delete signedRequest.headers['Content-Length']

let response = await axios(signedRequest)

This article might help you with the basic code to get temporary credentials from cognito and authenticate the user.