rules.json

{
    "rules": {
      ".read" : false,
      ".write" : false,
      "queue": {
        ".read": false,
        ".write": "auth!=null",
        ".indexOn": "_state",
        "$taskID": {
          ".validate": "newData.hasChildren(['user', 'username', 'message', 'published']) || newData.hasChildren(['_state', '_state_changed', '_progress'])",
          "_state": {
            ".validate": "newData.isString()"
          },
          "_state_changed": {
            ".validate": "newData.isNumber() && (newData.val() === now || data.val() === newData.val())"
          },
          "_owner": {
            ".validate": "newData.isString()"
          },
          "_progress": {
            ".validate": "newData.isNumber() && newData.val() >= 0 && newData.val() <= 100"
          },
          "_error_details": {
              "error": {
                ".validate": "newData.isString()"
              },
              "previous_state": {
                ".validate": "newData.isString()"
              },
              "original_task": {
                /* This space intentionally left blank, prevents $other from matching on malformed task */
              },
              "$other": {
                ".validate": false
              }
          },
          "user": {
            ".validate": "newData.val() === auth.uid"
          },
          "username": {
            ".validate": "newData.val() === root.child('users/' + auth.uid + '/username').val()"
          },
          "message": {
            ".validate": "newData.isString()"
          },
          "published": {
            ".validate": "newData.isNumber()"
          },
          "$other": {
            ".validate": false 
          }
        }
      },
      "jobs" : {
        ".read": false,
        ".write": false,
        "$jobID": {
          ".validate": "newData.hasChild('in_progress_state')",
          "start_state": {
            ".validate": "newData.isString()"
          },
          "in_progress_state": {
            ".validate": "newData.isString()"
          },
          "finished_state": {
            ".validate": "newData.isString()"
          },
          "error_state": {
            ".validate": "newData.isString()"
          },
          "timeout": {
            ".validate": "newData.isNumber() && newData.val() > 0"
          },
          "$other": {
            ".validate": false
          }
        }
      },
      "messages": {
        ".read": "auth!=null",
        ".write": false,
        "$messageID": {
          ".validate": "newData.hasChildren(['user', 'username', 'message', 'published'])",
          "user": {
            ".validate": "newData.val() === auth.uid"
          },
          "username": {
            ".validate": "newData.val() === root.child('users/' + auth.uid + '/username').val()"
          },
          "message": {
            ".validate": "newData.isString()"
          },
          "published": {
            ".validate": "newData.isNumber()"
          },
          "$other": {
            ".validate": false 
          }
        }
      },
      "users": {
        ".read": true,
        ".write": false,
        "$userID": {
          ".read": "auth.uid === $userID",
          ".write": "auth.uid === $userID",
          ".validate": "newData.hasChildren(['pic', 'username'])",
          "username": {
            ".validate": "newData.isString()"
          },
          "pic": {
            ".validate": "newData.isString()"
          },
          "$other": {
            ".validate": false
          }
        }
      }
    }
}