title: How to call Firebase Callable Functions with HTTP?
body: <p>I realised that the new <a href="https://firebase.google.com/docs/functions/callable" rel="noreferrer">Callable Cloud Functions</a> can still be called as if they were <a href="https://firebase.google.com/docs/functions/http-events" rel="noreferrer">HTTP events</a>, i.e. they can still be reached under <code>http://us-central1-$projectname.cloudfunctions.net/$functionname</code>. When doing that I receive an error message in my <em>Cloud Functions Log</em>:</p>
  
  <pre><code>Request has invalid method. GET 
  </code></pre>
  
  <p>This means that <em>HTTP-GET</em> does not work, but is there a way to call the functions? Maybe they are using <em>HTTP-CONNECT</em>.</p>