Mapping multiple values for a requestParameter key

Question

Hello there,  
  
Is it possible to pass multiple values to a single request parameter key in integration requests? JSON like or encoded string?  
  
**A typical use case could be passing the `sub` property from the authorizer in the SNS message payload, together with other parameters**  
  
So far I have tried this:

```
integration.request.querystring.Message.foo: method.request.path.foo
integration.request.querystring.Message.bar: method.request.path.bar
integration.request.querystring.Message.userId: context.authorizer.claims.sub
```

But when I make the request via Postman I have this error:

```
    "Error": {
        "Code": "MalformedInput",
        "Message": "Start of list found where not expected",
        "Type": "Sender"
    },
```

Is this even possible? The docs do not mention it

Accepted Answer

It's not possible via the parameter mapping but doable within the request body mapping template with request override feature.  
https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-override-request-response-parameters.html  
  
Please note that the request/response override is only available in REST API.

Answer

up please =)

Answer

Hello, first of all, thank you very much for the response.  
  
And yes it worked by using mapping template, I thought they were only for body.  
  
This is the working solution, under

```
 requestTemplates:
                  application/json:
```

```
#set($foo = $input.params('foo'))
#set($userId = $context.authorizer.claims.sub)
$input.json("$")
#set($context.requestOverride.querystring.Message = "{
    ""foo"":  ""$foo"",    
    ""userId"" : ""$userId""
}")"
```

Answer

For a mix of numeric and associative arrays one can use this syntax as well:

```
#set($context.requestOverride.querystring['filter[0][action]'] = "where")
#set($context.requestOverride.querystring['filter[0][attribute]'] = "status")
```

Mapping multiple values for a requestParameter key

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