<aside> 💡 to save and retrieve data from the Firebase Cloud Firestore

</aside>

• 파이어베이스의 essential 파이아스토오오옴🔥🔥🔥🔥🔥🔥🔥
• 메세지를 저장하고 다른 유저에게 전달하기 위해서 사용!!
• 배울 것 : Save data, retrieve data, listen for update data, sort, query

Cloud Firestorm

How to use Firestorm

1. Create a new database

   1. go to Console - choose project - select 'FireStore database'
   2. create database - mode (test) - location (Seoul : northeast3)

2. Set up your development environment

   pod 'Firebase/Firestore'
   

3. Initialize Cloud FireStore

   //AppDelegate.swift
   import Firebase
   
   FirebaseApp.configure()
   
   let db = Firestore.firestore()
   

   [test db]

   func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
       // Override point for customization after application launch.
       FirebaseApp.configure()
       let db = Firestore.firestore()
       print(db)
       return true
   }
   
   //print result: <FIRFirestore: 0x600000ecff40>
   

Save Data

<aside> 💡 관계형 db와 몽고db 용어 차이 : https://javacpro.tistory.com/66

</aside>

1. 예를들어, 메세지 모델이 다음과 같다면,

   struct Message {
       let sender: String //email addr
       let body: String
   }
   

2. body ⇒ input data in TextField

3. sender ⇒ currently signed in user! - Manage User

   //currentUser property
   
   if Auth.auth().currentUser != nil {
     // User is signed in.
     // ...
   } else {
     // No user is signed in.
     // ...
   }
   // Add a new document with a generated ID
   var ref: DocumentReference? = nil
   ref = db.collection("users").addDocument(data: [
       "first": "Ada",
       "last": "Lovelace",
       "born": 1815
   ]) { err in
       if let err = err {
           print("Error adding document: \\(err)")
       } else {
           print("Document added with ID: \\(ref!.documentID)")
       }
   }
   

[sample code]

let db = Firestore.firestore()

@IBAction func sendPressed(_ sender: UIButton) {
    if let messageBody = messageTextfield.text, let messageSender = Auth.auth().currentUser?.email {
        //create the data dictionary
        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 save the data")
            }
        }
    }
}

Retrieve Data (되찾다, 회수하다, 가져오다)

• 저장된 메세지들을 전부 뷰에 보여줘야 되고