Curl successfully uploads the file to S3 using a signed url:

curl -v -k -X PUT \
  -H "x-amz-server-side-encryption: AES256" \
  -H "Content-Type: application/pdf" \
  -T "__tests__/resources/test.pdf" \
  "http://mybucket.s3.amazonaws.com/test.pdf?AWSAccessKeyId=IDKEY&Expires=1489458783&Signature=SIGNATURE

I've tried replicating this in Grails using the REST client plugin:

  String url = "http://mybucket.s3.amazonaws.com/test.pdf?AWSAccessKeyId=IDKEY&Expires=1489458783&Signature=SIGNATURE"
  RestResponse resp = rest.put(url){
      header "x-amz-server-side-encryption", "AES256"
      header "Content-Type", "application/pdf"
      body pdf
  }

But Amazon rejects the upload, saying the arguments are incorrect...probably due to the pdf being sent as a "body" parameter. Any ideas?