title: How to upload file using a post request in the node http library?
body: <p>From the Node.js http library docs:</p>
  
  <pre><code>http.request() returns an instance of the http.ClientRequest class. 
  The ClientRequest instance is a writable stream. If one needs to upload a file 
  with a POST request, then write to the ClientRequest object.
  </code></pre>
  
  <p>However I'm unsure how to leverage this in my current code:</p>
  
  <pre><code>var post_data = querystring.stringify({
      api_key: fax.api_key,
      api_secret: fax.api_secret_key,
      to: fax.fax_number,
      filename: ""
  });
  
  var options = {
      host: p_url.hostname.toString(),
      path: p_url.path.toString(),
      method: 'POST',
      headers: {
            'Content-Type': 'application/x-www-form-urlencoded',
            'Content-Length': post_data.length
      }
  };
  
  var postReq = http.request(options, function(res) {
      res.setEncoding('utf8');
      res.on('data', function (chunk) {
            console.log('Response: ' + chunk);
      });
  });
  
  postReq.write(post_data);
  postReq.end();
  </code></pre>