AWS API Gateway deployed API can't parse request body - amazon-web-services

Question

I have a Lambda function integrated with API Gateway and the stack was deployed as cloud formation template. When I try to test the endpoint in the AWS web console I got correct response but when I try to invoke the deployed version of the API I got that error.
"message": "Could not parse request body into json: Unrecognized token ....etc"
I tried this mapping { "body" : $input.json('$') } in the integration request, but didn't work.
Here is the JSON I am trying to send using POSTMAN
{
"description": "test description",
"status": "test status"
}
and the request has header: Content-Type: application/json
Here you are screenshots for POSTMAN request body & headers, and the response from the API:
Any Solution guys?
UPDATE:
I put a mapping template at integration request level as the following:
{
"body-json" : $input.json('$')
}
And updated the lambda function to log the coming request, then made 2 requests:
First one: from API Gateway test web console:
I found the following in the cloudwatch logs:
INFO {
body: {
description: 'test',
projectId: 23,
action: 'test',
entity: 'test',
startDate: '01-01-2020',
endDate: '01-01-2020'
}
}
Second one: from POSTMAN:
I found the following in the cloudwatch logs:
INFO {
body: 'ewogICAgImRlc2NyaXB0aW9uIjogInRlc3QiLAogICAgInByb2plY3RJZCI6IDIzLAogICAgImFjdGlvbiI6ICJ0ZXN0IiwKICAgICJlbnRpdHkiOiAidGVzdCIsCiAgICAic3RhcnREYXRlIjogIjAxLTAxLTIwMjAiLAogICAgImVuZERhdGUiOiAiMDEtMDEtMjAyMCIKfQ=='
}
That indicates that in case of making the request using POSTMAN, the JSON payload is stringified automatically. What can cause such thing? and how to deal with it?

Answer 1

In this case we need to edit the mapping template since we are not using a proxy integration.
"body-json" : $input.json('$')
//also if binary data type is enabled for your api your body will be a base64
//encoded string which could be decoded using
$util.base64Decode($input.json('$'))
Also binary data types maybe enabled by default, search for these in the SAM template
x-amazon-apigateway-binary-media-types:
- '*/*'

Answer 2

You need to add a custom header in your response for it to respond correctly.
// The output from a Lambda proxy integration must be
// in the following JSON object. The 'headers' property
// is for custom response headers in addition to standard
// ones. The 'body' property must be a JSON string. For
// base64-encoded payload, you must also set the 'isBase64Encoded'
// property to 'true'.
let response = {
statusCode: responseCode,
headers: {
"x-custom-header" : "my custom header value"
},
body: JSON.stringify(responseBody)
};