Accessing data in firebase realtime database swift - ios

Question

I'm new to firebase and I wanted to try using a realtime database. It's been fairly easy to use until it's time to fetch the data from the database. I'm currently stuck at trying to get the data back into an array to provide my tableView with data.
Each image is saved with a timestamp. I've fetching it in different ways, it ends up printing nil or breaking the app. But when i use a breakpoint, I'm able to see the same data.
func downloadFromFirebase(completion: #escaping (Bool, Error?) -> Void) {
ref.child("ImageDetails/").observeSingleEvent(of: .value) { (snapshot) in
guard let value = snapshot.value as? [String:Any] else { return }
let name = value["username"] as! String
completion(true, nil)
}
}

Answer 1

I don't understand your question so I will write a code in order to retrieve the data from realtime database and to save it in an array.
You said "Each image is saved with a timestamp", so I assume you want to retrieve an array of data containing images(imageURL, etc) right?
we create a structure based on your database
struct dataStructure {
var Description:String?
var imageURL:String?
var Portfolio:String?
var createdAt:String?
var Instagram:String?
var profileImageUrl:String?
var Twitter:String?
var Username:String?
}
// now we create an array of this struct
var arrayOfData = [dataStructure]()
func downloadFromFirebase(completion:#escaping (Bool ,Error?)-> Void) {
ref.child("ImageDetails/").observeSingleEvent(of: .value) { snapshot in
guard let value = snapshot.value as? [[String:Any]] else { return }
// we add each element of value in the arrayOfData
for element in value {
guard let name = value["username"] as! String,
let Description = value["Description"] as! String,
let imageURL = value["imageURL"] as! String,
let Portfolio = value["Portfolio"] as! String,
let creationDate = value["createdAt"] as! String,
let Instagram = value["Instagram"] as! String,
let profileImageUrl = value["profileImageUrl"] as! String,
let Twitter = value["Twitter"] as! String ,
let Username = value["Username"] as! String else {
completion(false)
return
}
arrayOfData.append(dataStructure(name: name,
Description: Description,
imageURL: imageURL,
Portfolio: Portfolio ,
creationDate:creationDate ,
Instagram: Instagram,
profileImageUrl: profileImageUrl,
Twitter: Twitter))
}
completion(true)
}
}
at the end you will have an array with all your data
here is the code if you want to take the data from this function in your completion
func downloadFromFirebase(completion:#escaping (Result<dataStructure, Error>) {
ref.child("ImageDetails/").observeSingleEvent(of: .value) { snapshot in
guard let value = snapshot.value as? [[String:Any]] else { return }
// we add each element of value in the arrayOfData
for element in value {
guard let name = value["username"] as! String,
let Description = value["Description"] as! String,
let imageURL = value["imageURL"] as! String,
let Portfolio = value["Portfolio"] as! String,
let creationDate = value["createdAt"] as! String,
let Instagram = value["Instagram"] as! String,
let profileImageUrl = value["profileImageUrl"] as! String,
let Twitter = value["Twitter"] as! String ,
let Username = value["Username"] as! String else {
completion(.failure(error)
return
}
arrayOfData.append(dataStructure(name: name,
Description: Description,
imageURL: imageURL,
Portfolio: Portfolio ,
creationDate:creationDate ,
Instagram: Instagram,
profileImageUrl: profileImageUrl,
Twitter: Twitter))
}
/* we provide the array with the new data in the completion at the
end of the loop */
completion(.success(arrayOfData))
}
}