Assigning firestore data to custom object - ios

Question

I am trying to make an app that uses Firestore to store customer specific specs. I have a spec object that only has a few properties for now, but I need to take the data and assign it to a new Spec object, which then will be appended to an array to display on a tableView. I don't understand how to access the individual maps in the array to assign the values to each property for the spec. I currently have it set to print in the console, as every time I try to assign a value from the document it is nil. Essentially I need to store data under customers(a total list of all the customers) and among other data have an array of specs that contain specNumber, specDescription, and palletCount for each customer.
example:
Customer: Test
Specs:
3096:
Description: 50#top
pltCount: 250
3097:
Description: 50#bottom
pltCount: 250
Firestore data:
enter image description here
Code:
let settings = FirestoreSettings()
Firestore.firestore().settings = settings
db = Firestore.firestore()
db.collection("customers/test/specs")//.whereField("isCustomer", isEqualTo: true)
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in querySnapshot!.documents {
print("\(document.documentID) => \(document.data())")
}
}
}
Spec calls code:
struct Spec {
// Properties
var specNumber: String
var specDescription: String
var palletCount: Int
//var palletsOrdered = 0
init(specNum: Int, specDesc: String, pltCount: Int) {
specNumber = "\(specNum)"
specDescription = specDesc
palletCount = pltCount
}
}

Answer 1

You must separate access to documents from access to data within documents (you attempt to do it together). You cannot call getDocuments() on a document or a field within a document, only on a collection. So instead of db.collection("customers/test/specs").getDocuments(), try:
db.collection("customers").getDocuments() { (snapshot, error) in ... }
Then to get data from the documents:
db.collection("customers").getDocuments() { (snapshot, error) in
if let snapshot = snapshot { // lead by unwrapping the snapshot instead of the error
for doc in snapshot.documents { // iterate through the documents
guard let specs = doc.get("specs") as? [[String: Any]] else {
continue // continue loop
}
for s in specs { // iterate through the array of specs
if let specNum = s["SpecNum"] as? String,
let specDesc = s["SpecDesc"] as? String,
let pltCount = s["PalletCount"] as? Int {
let spec = Spec(specNum: specNum, specDesc: specDesc, pltCount: pltCount)
self.someArray.append(spec)
}
}
self.tableView.reloadData() // loop is done, reload
}
} else {
if let error = error {
print(error)
}
}
}
This is a very simplified version of how I imagine you'd actually want to implement it, depending on how the table/collection was reloaded (on the fly, routinely, or just once). Also, each document contains an array of specs but you're fetching all documents from the collection, which would give you a ton of specs without any indication of which spec is tied to which customer. But I suspect this is just early setup and you're just trying to get a handle on the API first.
Note: Maps in Firestore are called dictionaries in Swift and they always come back from Firestore as [String: Any] dictionaries. That's why when we originally unwrapped the specs map, we cast it as an array of dictionaries:
let specs = doc.get("specs") as? [[String: Any]]