api gateway and step functions

Question

Hi,
i've created an Api Gateway that calls a state machine.
The problem i have is that when you invoke this service from out you need to specify a stateMachineArn.
It seems a lack of security. There's a way to pass it as integration of the request (for example as a constant)?
I have tried some solutions as mapping templates but it seems that they does'n work , i always had this error:
Value null at 'stateMachineArn' failed to satisfy constraint: Member must not be null"
thanks in advance.

Answer

Value null at 'stateMachineArn' failed to satisfy constraint: Member must not be null"

The same problem raised for me while posting data to DynamoDB table through API Gateway.

How I solved that error:
   By adding a Body-Mapping template in the Integration Request

In the API > whatever resource > whatever method > Integration Request > Body mapping template, added a new template "application/json" as given below

```
{

"TableName": "yourTableName",

"Item": {

"inputField1": {

"S": "$input.path('$.tableItemAttribute1')"

},

"inputField2": {

"S": "$input.path('$.tableItemAttribute2')"

},

"inputField3": {

"S": "$input.path('$.tableItemAttribute3')"

}

}
```

Answer

Thank You Anirban for your reply.
I've solved too adding a Body-Mapping template in the Integration Request.

{
    "input": "$util.escapeJavaScript($input.json('$'))",
    "stateMachineArn": "arn:aws:MyStateMachine"
}
it works, you must remember to redeploy the api gateway.
Thanks.
Dryuyd

api gateway and step functions

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