title: Is a POST request with an empty body and a response of a pure ID value in text format RESTful
body: <p>In our <em>REST API</em> project with a <em>jax-rs</em> based framework, there is one customer <em>endpoint</em>:</p>
  
  <p><code>customer/</code></p>
  
  <p>This endpoint has a <em>POST</em> method with an <strong>empty input body</strong>, and the <strong>response</strong> with status SUCCESS (201) is just an automatically generated <strong>ID value in pure text format</strong>, meaning neither <em>JSON</em> nor <em>XML</em>.</p>
  
  <p><strong>Question 1: is it normal to make a POST request with an empty input body in a RESTful API?</strong></p>
  
  <p><strong>Question 2: Is the implementation of returning only a value in pure text format still a valid RESTful API? Is this implementation a good practice at all? What is the problem of such implementation? How to improve it?</strong> Personally I really feel odd on such implementation but I am really not able to tell the problem of it  </p>
  
  <p>If I implement the POST method, I probably would return a JSON or an xml format response instead of a pure text value, sth like:</p>
  
  <p><code>{id: 1234567}</code> </p>