How to read a S3 file from a REST Endpoint using Apache Camel 2.X

Question

I need to read a file from S3 bucket based on the file name passed from a REST endpoint. The file name will be passed as a uri parameter. The camel route I am using is given below.

rest().get("/file")
     .to("direct:readFile");

from("direct:readFile")
     .setProperty("FileName",simple("${header.fileName}"))
     .log(LoggingLevel.INFO, "Reading file from S3")
     .setHeader(S3Constants.KEY, simple("${header.fileName}"))
     .to("aws-s3://"+awsBucket+"?amazonS3Client=#s3Client&fileName=${header.fileName}")
     ...

Instead of reading the file, this is currently overwriting the existing file in S3 with an empty file. How do I specify that this is a read operation and not a write operation?

I know that the latest version has an operation=getObject parameter for this. But the version I am using is 2.18.1 as the rest of the application is also on this version, and this version does not support this operation.

Is there any other way to achieve this?