CODEWITHSUNDEEP
swiftfirebasefirebase-realtime-database
Bogy
Bogy

Reputation: 964

How to query items with timestamps on Firebase?

I want to query active items from a Firebase node. An active item is delimited by a start date and an end.
Here is a sample of the structure :

{
    "items" : {
        "itme1" : {
            "data" : "...", //some data
            "startDate" : 12345678,
            "endDate" : 23456789
        },
        "item2" : {...}
    }
}

Dates are Firebase timestamps to prevent user time shifting.
An item is saved on Firebase server like this:

//Init data to save
var dictionary = Dictionary<String,Any>()
dictionary["data"] = "some data"
dictionary["startDate"] = FIRServerValue.timestamp()

//Save data on Firebase
let itemRef = FIRDatabase.database().reference(withPath: "items").childByAutoId()
itemRef.setValue(dictionary)

//Set end date
itemRef.observeSingleEvent(of: FIRDataEventType.value, with: { (snapshot) in
    if let dict = snapshot.value as? NSDictionary, let createdAt = dict["startDate"] as? TimeInterval {
        let startDate = Date(firebaseTimestamp: createdAt)
        let endDate = startDate.dateByAddingHours(1) //Add one hour to startDate
        itemRef.updateChildValues(["endDate":endDate.timeIntervalSince1970 * 1000])
    }
})

How can I query Firebase to get items where endDate >= FIRServerValue.timestamp() (active items) ?

As firebase timestamp FIRServerValue.timestamp() can only be known only after it has been written on Firebase, I cannot query FIRServerValue.timestamp() directly. Maybe there is a better way to set endDate. How do people handle this?

Upvotes: 1

Views: 2607

Answers (1)

chickenparm
chickenparm

Reputation: 1620

You could try something like this. This would only query items where the end date equals the current date or greater.

let removeBeforeThisDate = NSDate()
let currentDateTimestamp = removeBeforeThisDate.timeIntervalSince1970

itemRef.queryOrderedByChild("endDate").queryStartingAtValue(currentDateTimestamp).observeEventType(.Value, withBlock: { snapshot in
...

Upvotes: 1

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