How can I reference second level collections in Firebase? - swift

Question

Currently my Firebase database is using the following structure
Users
User 1 Data
User 2 Data...
However I have created a new collection inside of the "users" collection called "products" which will store product details that users have uploaded on the application.
How can I ensure that once a user uploads a new product, it is only uploaded into their 'User X data' dataset, inside the respective "products" collection. The code I currently have only uploads the data into the "users" collection, with no reference of the users who added the product as required. I have shown the structure of my Firebase database below for reference.
Here is my code:
let user = Auth.auth().currentUser
db.collection("users").getDocuments { (snapshot, error) in
if let error = error {
print(error)
return
} else {
for document in snapshot!.documents {
let data = document.data()
let userId = data["uid"] as! String
if userId == user?.uid {
db.collection("users").document("products").setData(["productNameField":firstName, "productURLField":lastName,"productPriceField":ebayName, "productDescriptionField":etsyName, "productTimeRemainingField":email])
}
}
}
}
How would I go about updating my code to achieve this?

Answer 1

I think you're looking for
let user = Auth.auth().currentUser
db.collection("users").getDocuments { (snapshot, error) in
if let error = error {
print(error)
return
} else {
for document in snapshot!.documents {
let data = document.data()
let userId = data["uid"] as! String
if userId == user?.uid {
document.reference.collection("products").addDocument(["productNameField":firstName, "productURLField":lastName,"productPriceField":ebayName, "productDescriptionField":etsyName, "productTimeRemainingField":email])
}
}
}
}
So here document is the DocumentSnapshot that you're looping over, so document.reference gives you the reference to that specific document, and document.reference.collection("products") then points to the `products subcollection for that specific document.

Answer 2

You're wastefully looping over the entire list of users to FIND the user document needed. Simplify, simplify - use the user.uid as the Id of the user document!! (i.e. when you create the user document, save it as
db.collection("users").doc(user.uid).set({whatever})
...then it's trivial to access as...
let user = Auth.auth().currentUser
db
.collection("users")
.doc(user.uid)
.collection("products")
.setData([
"productNameField":firstName,
"productURLField":lastName,
"productPriceField":ebayName,
"productDescriptionField":etsyName,
"productTimeRemainingField":email
]);
If there is another reason to keep the docID and the uid separate (not shown here), then use a query to get the SPECIFIC document with the uid, rather than downloading ALL of them
let user = Auth.auth().currentUser
db
.collection("users")
.where(field: "uid", opStr:"==", value: user.uid)
.getDocuments( { (snapshot, error) in
if let error = error {
print(error)
return
} else { //the query should only return the one document, but queries always return an array
snapshot
.documents[0]
.ref()
.document("products")
.setData([
"productNameField":firstName,
"productURLField":lastName,
"productPriceField":ebayName,
"productDescriptionField":etsyName,
"productTimeRemainingField":email
])
}
}
...etc...
I don't generally use Swift, so the where clause may require different formatting, but the idea is GET ONLY THE DOCUMENT YOU NEED. Your security rules should only be allowing this, anyway.