title: Firebase Rate Limiting In Realtime Database Rules Language
body: <p><br>
  I am currently trying to implement rate limting by checking the timestamp of the last post and then add + 60sec to it and then check if it is smaller(&lt;) then the current Firebase Server Timestamp(now). 
  It somehow always returns true and grants access ?!
  <br><br><strong>These are my Rules:</strong></p>
  
  <pre><code>{
    "rules": {
          "posts": {
          ".read": true,
              ".write": 
  "(root.child('users').child(auth.uid).child('lastPost').val() + 60) &lt; now"
        }
    }
  }
  </code></pre>
  
  <p><br><br><br>
  <strong>This is my database structure</strong>
  <br></p>
  
  <pre><code>{
      "posts": {
          "-KV70ppGGTEtXY4_Q4UC": {
              "author": "abcdedef-uid-ojifgoöifjgssgd",
              "description": "Thats the post description",
              "title": "Thats the post title"
          }
      },
      "users": {
          "2uy7323nTodMHcVxeEDJzoexH302": {
              "canPost": true,
              "email": "cryptic.pug@firebase.com",
              "lastPost": 14776667681,
              "profile_picture": "https://lh3.googleusercontent.com/-XdUIqdMkCWA/AAAAAAAAAAI/AAAAAAAAAAA/4252rscbv5M/photo.jpg",
              "username": "Cryptic Pug"
          }
      }
  }
  </code></pre>