title: Listen to object change in AWS S3 (AWS SDK)
body: <p>In AWS S3, I have a bucket named <code>'my-bucket'</code>, under <code>my-bucket</code> I have the following structure:</p>
  
  <pre><code>my-bucket/
      customers/
           products/
                - data1.txt
                - data2.txt
  </code></pre>
  
  <p>with <a href="https://aws.amazon.com/sdk-for-ruby/" rel="nofollow">AWS Ruby SDK</a>, I can list all the items under <code>my-bucket</code> by ruby code:</p>
  
  <pre><code>require 'aws-sdk'
  
  s3 = Aws::S3::Resource.new(region: 'us-west-2')
  
  bucket = s3.bucket('my-bucket')
  
  # Show only the first 50 items
  bucket.objects.limit(50).each do |item|
    puts "Name:  #{item.key}"
  end
  </code></pre>
  
  <p>This is fine, I am wondering is it possible to have a <strong>listener</strong> listen to any new file object uploaded to <code>my-bucket/customers/products/</code> with AWS Ruby SDK? If possible, how to do it?</p>