Retrieving Location Data with Radius using Firebase & GeoFire

Question

I am trying to use GeoFire to retrieve and according to radius (for example, everything in 10km distance).

To remain clear, I am saving the details and location separately in the database, so details' id is same with locations' id. While saving the data, I use:

 var details = ["a":"a", "b":"b", etc]
 let checkpointRef = eventRef.childByAutoId()
 checkpointRef.setValue(details)
 let checkpointId = checkpointRef.key

 let geofireRef = ref.childByAppendingPath("checkpointLocations")
 let geoFire = GeoFire(firebaseRef: geofireRef)

 geoFire.setLocation(CLLocation(latitude: usersLatitude, longitude: userLongitude), forKey: checkpointId) {...

Until here, everything seems fine in database.

---

While retrieving data, after getting user's latitude and longitude from core location, I am trying to :

func retrieve() {
   let geofireRef = Firebase(url: self.baseurl + "/checkpointLocations")
   let geoFire = GeoFire(firebaseRef: geofireRef)

   let center = CLLocation(latitude: usersLatitude, longitude: usersLongitude)

   var circleQuery = geoFire.queryAtLocation(center, withRadius: 10)

   circleQuery.observeEventType(.KeyEntered, withBlock: { (key: String!, location: CLLocation!) in
        print("Key '\(key)' entered the search area and is at location '\(location)'")
    })

First problem arises here with observeEventType(). I don't want to observe event continuously. Instead, like a classic TableView, I want to retrieve the data once and display, and re-retrieve data with "pull to refresh" functionality. My first question is, are there any function for GeoFire to work as observeSingleEventOfType of Firebase and retrieve data once?

---

Secondly, this function is printing this warning couple of times:

[Firebase] Using an unspecified index. Consider adding ".indexOn": "g" at /checkpointLocations to your security rules for better performance

..but doesn't log anything else. I don't think it goes inside the function because it doesn't print the print("Key.. part. It doesn't also print("A").

I thought it might be caused because of the 'Firebase Rules'. Using this answer on SO, I tried adding this:

 "rules": {
    "checkpointLocations": {
      "$key": {
        ".read": true,
        ".write": true,
        "geofire": {
          ".indexOn": "g"
        }
      }
    }
  }

and also this:

 "rules": {
    "checkpointLocations": {
      ".read": true,
      ".write": true,
      "geofire": {
        ".indexOn": "g"
      }
    }
  }

But neither works.

Update:

Using @Gregg's answer, I fixed the warnings, however, it still doesn't go inside the closure.

Answer 1

Dont have enough points for commenting but move the ".indexOn" up to the checkpointLocations node. Currently you have it on checkpointLocations/geofire. For example:

"rules": {
    "checkpointLocations": {
      ".read": true,
      ".write": true,
      ".indexOn": "g"
      "geofire": {

      }
    }
  }