title: Can't return a xlsx file from a Node.js (express) service which gets it from a S3 bucket, for use by a browser app
body: <p>Created a xlsx file in Excel, uploaded from desktop manually to AWS S3 via console.
  Now want to add an endpoint to a Node.js express service that will retrieve that file from S3 and pass it back to a javascript browser application.</p>
  <p>Seems fine with plain text file, but keep getting HTTP status code 500 for the xlsx file (and even csv created in Excel).</p>
  <p>tried variations like:</p>
  <pre class="lang-js prettyprint-override"><code>res.send(s3.getObject().toString()); //this works with plain text file
  </code></pre>
  <pre class="lang-js prettyprint-override"><code>res.send(s3.getObject().toString('utf-8'));
  </code></pre>
  <pre class="lang-js prettyprint-override"><code>res.send(s3.getObject().toString('binary'));
  </code></pre>
  <p>no luck with any of these, call fails immediately with 500 Internal Server error.</p>