API Gateway to Step Functions transform and enrich payload in a mapping template

Question

Right now I'm struggling to create the following input for a step function:
```
#set($data = {
"auth": {
    "tenantId": "foo",
    "userId": "bar",
    "groups": "baz"
},
"data": $input.path('$')
})   
{ 
    "stateMachineArn": "myArn",     
    "input": $util.escapeJavaScript($data).replaceAll("\'","'")
}
```
Where `foo`, `bar`, `baz` are replaced by `$context...` elements which are not available in the test area of API Gateway afaik.
In the API Gateway Method Test I can see that this payload is generated:
```
Endpoint request body after transformations: { 
    "stateMachineArn": "myArn",
    "input": {auth={tenantId=foo, userId=bar, groups=baz}, data={Test=Test}}
}
```
Based on my template I expected a output like this:
`"{"auth":{"tenantId":"foo","userId":"bar","groups":"baz"},"data":{"test":"test"}}"` for the `"input"`.

Why is that not happening?

Accepted Answer

Hi,

Take a look at the following implementation example, I hope it will help you.

**Code**
```
#set($data='{ "auth":{"tenantId":"foo", "userId":"bar", "groups":"baz"}, "data" :'+$input.json('$')+'}')
#set($data=$util.escapeJavaScript($data))
{
  "input" :"$data",
  "stateMachineArn": "myArn"
}
```

**Input**

```
{
  “Test”: “Test"
}
```

**Output**

```
{
  "input" :"{ \"auth\":{\"tenantId\":\"foo\", \"userId\":\"bar\", \"groups\":\"baz\”},  \”data\”: { \”Test\":\”Test\”}}",
  "stateMachineArn": "myArn"
}
```

API Gateway to Step Functions transform and enrich payload in a mapping template

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