Raw body payload in AWS API Gateway Body Mapping Template - json

Question

For some reason I'm having a hard time getting the raw body from within the event. It's logging the $input.body as json for a application/json content-type. The docs say that that should contain the raw payload.
Here my Integration Request Body Mapping Template:
{
"body" : $input.json('$'),
"rawBody": $input.body,
"headers": {
#foreach($header in $input.params().header.keySet())
"$header": "$util.escapeJavaScript($input.params().header.get($header))" #if($foreach.hasNext),#end
#end
},
"method": "$context.httpMethod",
"params": {
#foreach($param in $input.params().path.keySet())
"$param": "$util.escapeJavaScript($input.params().path.get($param))" #if($foreach.hasNext),#end
#end
},
"query": {
#foreach($queryParam in $input.params().querystring.keySet())
"$queryParam": "$util.escapeJavaScript($input.params().querystring.get($queryParam))" #if($foreach.hasNext),#end
#end
}
}
Here's the payload example:
{
"event": {
"body": {
"hello": "meow"
},
"rawBody": {
"hello": "meow"
},
"headers": {
"Accept": "*/*",
"Accept-Encoding": "gzip, deflate",
"Accept-Language": "en-US",
"Cache-Control": "no-cache",
"CloudFront-Forwarded-Proto": "https",
"CloudFront-Is-Desktop-Viewer": "true",
"CloudFront-Is-Mobile-Viewer": "false",
"CloudFront-Is-SmartTV-Viewer": "false",
"CloudFront-Is-Tablet-Viewer": "false",
"CloudFront-Viewer-Country": "US",
"Content-Type": "application/json",
"Host": "7nuy7lymef.execute-api.us-east-1.amazonaws.com",
"Origin": "file://",
"Postman-Token": "0ce7c6f4-3864-c9b4-f2db-739737b2ba49",
"User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Postman/4.2.2 Chrome/47.0.2526.73 Electron/0.36.2 Safari/537.36",
"Via": "1.1 1eea0bca59557555878da4d9775c509f.cloudfront.net (CloudFront)",
"X-Amz-Cf-Id": "SDjaGcuJ5eVkOMMCn6M3vGaVicA1fuA7h0bUYE4ARlKupO60eeYNFA==",
"X-Forwarded-For": "206.71.230.14, 205.251.250.135",
"X-Forwarded-Port": "443",
"X-Forwarded-Proto": "https",
"x_example_header": "my awesome header"
},
"method": "POST",
"params": {},
"query": {
"example_param": "myawesomeparam"
}
},
"context": {
"callbackWaitsForEmptyEventLoop": false,
"logGroupName": "/aws/lambda/reggi-log-post",
"logStreamName": "2016/06/08/[$LATEST]aad04e0e46614c288ac8ca43d0a95076",
"functionName": "reggi-log-post",
"memoryLimitInMB": "128",
"functionVersion": "$LATEST",
"invokeid": "6e4e1e13-2dc1-11e6-a1f7-4dad3a8eb122",
"awsRequestId": "6e4e1e13-2dc1-11e6-a1f7-4dad3a8eb122",
"invokedFunctionArn": "arn:aws:lambda:us-east-1:562508364089:function:reggi-log-post"
}
}
Is there any way to access the raw body from this request?
Is there any way to change the content-type to accept all types?

Answer 1

The following blog post explains in detail how to get around this problem. https://nicholasjackson.io/2016/12/13/using-graphql-with-aws-lambda/
It's written specifically in the context of GraphQL, but it will work for any content type. In short:
Go to the Binary Support section. Enable binary support for your chosen media type and save.
Return to the your method in Resources section and open Integration Request. Add/edit the body mapping template for your chosen content type and put the following:
"rawBody": "$util.escapeJavaScript($util.base64Decode($input.body))"
Save and redeploy the API.
Adding binary support encodes the request as a base64 string. The body mapping template decodes it.

Answer 2

$input.body contains the raw payload. You need to put quotes around it like "rawBody": "$input.body". Otherwise the body will be interpreted as part of the json document.