getdocuments function 不停

Question

so I'm trying to get data from firestore using this functionL

static func getData() -> [Post]{
    let db = Firestore.firestore()
    var posts = [Post]()
    db.collection("Posts").getDocuments { querySnapshot, error in
        guard let snapshot = querySnapshot else {
            print("Error retreiving snapshots \(error!)")
            return
        }
        
        for document in snapshot.documents{
            posts.append(Post(t: document.data()["title"] as? String ?? "", a: document.data()["author"] as? String ?? "", pm: document.data()["priceMax"] as? Double ?? 0.0, c: document.data()["content"] as? String ?? ""))
            print("New Post... ")
            print(document.data())
            print(posts.count)
            print(posts[0].title)
            }
        return
    }
    print("test")
    return posts
}

and from the print statements I can tell that it gets the data, but the function never ends. print("test") never runs, and thus the posts are never returned. How can I change this so that it returns the data?

Answer 1

Getting data from Firestore is an asynchronous call. Try this out:

func getData(completion: @escaping([Post], Error?) -> Void) {
        let db = Firestore.firestore()
        var posts = [Post]()
        db.collection("Posts").getDocuments { querySnapshot, error in
            guard let snapshot = querySnapshot else {
                print("Error retreiving snapshots \(error!)")
                completion(posts, error)
            }
            
            for document in snapshot.documents{
                posts.append(Post(t: document.data()["title"] as? String ?? "", a: document.data()["author"] as? String ?? "", pm: document.data()["priceMax"] as? Double ?? 0.0, c: document.data()["content"] as? String ?? ""))
                print("New Post... ")
                print(document.data())
                print(posts.count)
                print(posts[0].title)
                }
            completion(posts, error)
        }
    }

Then call the function like this:

getData { posts, error in
     print("Posts: \(posts)")
}