S3DownloadController.apxc

public class S3Controller {

    @AuraEnabled
    public static FileData GetS3FileUsingFileId(string recordId)
    {
        String key = '**************'; 
        String secret = '*********************************';
        String bucket = 'salesforcecodex'; 
        String host = 's3-us-west-1.amazonaws.com';
        String method = 'GET';
        AWSService service=new AWSService(key,secret,bucket,method,host);
       	FileData data=service.GetDocumentUsingFileId(recordId);
        return data;
    }
}