iOS & Swift 공부 - Database Setup and Saving Data to Firebase (영)

• We are going to use Cloud Firestore

  (There is Cloud Firestore & Realtime Databse)

  
  

• Head to your project console, and "create database"
  

• Start in test mode
• Make sure the necessary pods are installed
  
• The next step is to initialize the Cloud Firestore

(must write in AppDelegate.swift)

• Now, we made our database → We are now ready to put in data

• In my app, since I am developing a chat app, we need to tap into the "current user" online.

→ If we check the Firebase documents, we can see that we are able to get the currently signed-in user by using the below code:

if Auth.auth().currentUser != nil {
  // User is signed in.
  // ...
} else {
  // No user is signed in.
  // ...
}

(currentUser is an optional, so we need to check if it is nil or not)

→ First, you need a reference to the DB to actually access it within the view controller

• Now how do we add data to Firestore? → Check the documents as well

→ We access the db using the collection (dictionary).

• Since this is a chat app, we ultimately need the "sender" and the "body" to be saved to the DB.

→ messageTextfield.text is the chat message that the user types, and Auth.auth().currentUser?.email is the currently signed in user's email

→ Since both are Optionals, we need to optionally bind the values into separate constants (messageBody and messageSender)

→ Once optional binding is successful, we can then tap in to the DB using the code below.

@IBAction func sendPressed(_ sender: UIButton) {
        
        // Optional Binding -> Checking if both are not nil first
        if let messageBody = messageTextfield.text, let messageSender = Auth.auth().currentUser?.email{
            
            // Then, we send the data to the DB
            db.collection(K.FStore.collectionName).addDocument(data: [K.FStore.senderField: messageSender, K.FStore.bodyField: messageBody]) { (error) in
                if let e = error{
                    print("There was an issue saving data to firestore, \(e)")
                }
                else{
                    print("Successfully saved data")
                }
            }
        }
    }

(Constants.swift)

→ Notice we are sending the data in a Dictionary format.

• If the data is saved successfully without errors, the DB will look like this.

db.collection(K.FStore.collectionName).addDocument(data: [K.FStore.senderField: messageSender, K.FStore.bodyField: messageBody])

→ Take a look at the code above.

K.Fstore.collection name is the name of the newly created "collection" in Cloud Firestore. Then, we add a document (addDocument) within this newly created collection, with a Dictionary that we have configured.