Admin Database API 簡介

透過 Admin SDK，您可以使用完整管理員權限或精細的有限權限來讀取及寫入即時資料庫資料。本文件將引導您將 Firebase Admin SDK 新增至專案，以便存取 Firebase Realtime Database。

Realtime Database 執行個體可在不同的地理區域中建立，並使用不同的 firebaseio.com 和 firebasedatabase.app 網址配置。Admin SDK 設定網址的方法可使用任一配置。如要瞭解目前支援的區域和網址配置，請參閱在 Firebase 專案中選取位置的相關指南主題。

Admin SDK 設定

如要在伺服器上開始使用 Firebase 即時資料庫，您必須先以所選語言設定 Firebase Admin SDK。

如果您想使用 Node.js SDK 做為用於最終使用者存取權的用戶端 (例如在 Node.js 桌面或物聯網應用程式中)，而非從特權環境 (例如伺服器) 存取管理員，則應改為按照設定用戶端 JavaScript SDK 的操作說明操作。

Admin SDK 驗證

您必須先使用 Firebase 驗證伺服器，才能透過 Firebase Admin SDK 從伺服器存取 Firebase Realtime Database。驗證伺服器時，您不會像在用戶端應用程式中那樣使用使用者帳戶憑證登入，而是使用 服務帳戶，向 Firebase 識別您的伺服器。

使用 Firebase Admin SDK 進行驗證時，您可以取得兩種不同的存取權層級：

Firebase Admin SDK 驗證存取層級
管理員權限	具備專案 Realtime Database 的完整讀取和寫入權限。請謹慎使用，以完成需要無限制存取專案資源的管理工作，例如資料遷移或重組。
權限受限	專案的 Realtime Database 存取權 (僅限伺服器所需的資源)。使用這個層級，完成有明確定義存取權需求的管理工作。舉例來說，當您執行摘要工作來讀取整個資料庫的資料時，您可以設定只讀安全性規則，然後初始化 Admin SDK，並限制該規則的權限，以防意外寫入資料。

使用管理員權限進行驗證

使用 Firebase 專案中具備「編輯者」角色的服務帳戶憑證初始化 Firebase Admin SDK 時，該執行個體將具備專案 Realtime Database 的完整讀取和寫入權限。

Java

// Fetch the service account key JSON file contents
FileInputStream serviceAccount = new FileInputStream("path/to/serviceAccount.json");

// Initialize the app with a service account, granting admin privileges
FirebaseOptions options = FirebaseOptions.builder()
    .setCredentials(GoogleCredentials.fromStream(serviceAccount))
    // The database URL depends on the location of the database
    .setDatabaseUrl("https://DATABASE_NAME.firebaseio.com")
    .build();
FirebaseApp.initializeApp(options);

// As an admin, the app has access to read and write all data, regardless of Security Rules
DatabaseReference ref = FirebaseDatabase.getInstance()
    .getReference("restricted_access/secret_document");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
  @Override
  public void onDataChange(DataSnapshot dataSnapshot) {
    Object document = dataSnapshot.getValue();
    System.out.println(document);
  }

  @Override
  public void onCancelled(DatabaseError error) {
  }
});

Node.js

var admin = require("firebase-admin");

// Fetch the service account key JSON file contents
var serviceAccount = require("path/to/serviceAccountKey.json");

// Initialize the app with a service account, granting admin privileges
admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  // The database URL depends on the location of the database
  databaseURL: "https://DATABASE_NAME.firebaseio.com"
});

// As an admin, the app has access to read and write all data, regardless of Security Rules
var db = admin.database();
var ref = db.ref("restricted_access/secret_document");
ref.once("value", function(snapshot) {
  console.log(snapshot.val());
});

Python

import firebase_admin
from firebase_admin import credentials
from firebase_admin import db

# Fetch the service account key JSON file contents
cred = credentials.Certificate('path/to/serviceAccountKey.json')

# Initialize the app with a service account, granting admin privileges
firebase_admin.initialize_app(cred, {
    'databaseURL': 'https://databaseName.firebaseio.com'
})

# As an admin, the app has access to read and write all data, regradless of Security Rules
ref = db.reference('restricted_access/secret_document')
print(ref.get())

Go

ctx := context.Background()
conf := &firebase.Config{
	DatabaseURL: "https://databaseName.firebaseio.com",
}
// Fetch the service account key JSON file contents
opt := option.WithCredentialsFile("path/to/serviceAccountKey.json")

// Initialize the app with a service account, granting admin privileges
app, err := firebase.NewApp(ctx, conf, opt)
if err != nil {
	log.Fatalln("Error initializing app:", err)
}

client, err := app.Database(ctx)
if err != nil {
	log.Fatalln("Error initializing database client:", err)
}

// As an admin, the app has access to read and write all data, regradless of Security Rules
ref := client.NewRef("restricted_access/secret_document")
var data map[string]interface{}
if err := ref.Get(ctx, &data); err != nil {
	log.Fatalln("Error reading from database:", err)
}
fmt.Println(data)

您的服務所具備的存取權限，取決於用來驗證身分的服務帳戶。舉例來說，您可以使用專案中具有「Reader」角色的服務帳戶，將服務限制為唯讀。同樣地，在專案中沒有任何角色的服務帳戶無法讀取或寫入任何資料。

以有限的權限進行驗證

最佳做法是服務應只存取所需的資源。如要進一步控管 Firebase 應用程式執行個體可存取的資源，請在安全性規則中使用專屬 ID 代表您的服務。接著設定適當的規則，讓服務可以存取所需的資源。例如：

{
  "rules": {
    "public_resource": {
      ".read": true,
      ".write": true
    },
    "some_resource": {
      ".read": "auth.uid === 'my-service-worker'",
      ".write": false
    },
    "another_resource": {
      ".read": "auth.uid === 'my-service-worker'",
      ".write": "auth.uid === 'my-service-worker'"
    }
  }
}

接著，在伺服器上初始化 Firebase 應用程式時，使用 databaseAuthVariableOverride 選項覆寫資料庫規則使用的 auth 物件。在這個自訂 auth 物件中，將 uid 欄位設為您在安全性規則中用來代表服務的 ID。

Java

// Fetch the service account key JSON file contents
FileInputStream serviceAccount = new FileInputStream("path/to/serviceAccountCredentials.json");

// Initialize the app with a custom auth variable, limiting the server's access
Map<String, Object> auth = new HashMap<String, Object>();
auth.put("uid", "my-service-worker");

FirebaseOptions options = new FirebaseOptions.Builder()
    .setCredential(FirebaseCredentials.fromCertificate(serviceAccount))
    // The database URL depends on the location of the database
    .setDatabaseUrl("https://DATABASE_NAME.firebaseio.com")
    .setDatabaseAuthVariableOverride(auth)
    .build();
FirebaseApp.initializeApp(options);

// The app only has access as defined in the Security Rules
DatabaseReference ref = FirebaseDatabase
    .getInstance()
    .getReference("/some_resource");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        String res = dataSnapshot.getValue();
        System.out.println(res);
    }
});

Node.js

var admin = require("firebase-admin");

// Fetch the service account key JSON file contents
var serviceAccount = require("path/to/serviceAccountKey.json");

// Initialize the app with a custom auth variable, limiting the server's access
admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  // The database URL depends on the location of the database
  databaseURL: "https://DATABASE_NAME.firebaseio.com",
  databaseAuthVariableOverride: {
    uid: "my-service-worker"
  }
});

// The app only has access as defined in the Security Rules
var db = admin.database();
var ref = db.ref("/some_resource");
ref.once("value", function(snapshot) {
  console.log(snapshot.val());
});

Python

import firebase_admin
from firebase_admin import credentials
from firebase_admin import db

# Fetch the service account key JSON file contents
cred = credentials.Certificate('path/to/serviceAccountKey.json')

# Initialize the app with a custom auth variable, limiting the server's access
firebase_admin.initialize_app(cred, {
    'databaseURL': 'https://databaseName.firebaseio.com',
    'databaseAuthVariableOverride': {
        'uid': 'my-service-worker'
    }
})

# The app only has access as defined in the Security Rules
ref = db.reference('/some_resource')
print(ref.get())

Go

ctx := context.Background()
// Initialize the app with a custom auth variable, limiting the server's access
ao := map[string]interface{}{"uid": "my-service-worker"}
conf := &firebase.Config{
	DatabaseURL:  "https://databaseName.firebaseio.com",
	AuthOverride: &ao,
}

// Fetch the service account key JSON file contents
opt := option.WithCredentialsFile("path/to/serviceAccountKey.json")

app, err := firebase.NewApp(ctx, conf, opt)
if err != nil {
	log.Fatalln("Error initializing app:", err)
}

client, err := app.Database(ctx)
if err != nil {
	log.Fatalln("Error initializing database client:", err)
}

// The app only has access as defined in the Security Rules
ref := client.NewRef("/some_resource")
var data map[string]interface{}
if err := ref.Get(ctx, &data); err != nil {
	log.Fatalln("Error reading from database:", err)
}
fmt.Println(data)

在某些情況下，您可能會希望將 Admin SDK 的範圍視為未經驗證的用戶端。方法是提供資料庫驗證變數覆寫的 null 值。

Java

// Fetch the service account key JSON file contents
FileInputStream serviceAccount = new FileInputStream("path/to/serviceAccountCredentials.json");

FirebaseOptions options = new FirebaseOptions.Builder()
    .setCredential(FirebaseCredentials.fromCertificate(serviceAccount))
    // The database URL depends on the location of the database
    .setDatabaseUrl("https://DATABASE_NAME.firebaseio.com")
    .setDatabaseAuthVariableOverride(null)
    .build();
FirebaseApp.initializeApp(options);

// The app only has access to public data as defined in the Security Rules
DatabaseReference ref = FirebaseDatabase
    .getInstance()
    .getReference("/public_resource");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        String res = dataSnapshot.getValue();
        System.out.println(res);
    }
});

Node.js

var admin = require("firebase-admin");

// Fetch the service account key JSON file contents
var serviceAccount = require("path/to/serviceAccountKey.json");

// Initialize the app with a null auth variable, limiting the server's access
admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  // The database URL depends on the location of the database
  databaseURL: "https://DATABASE_NAME.firebaseio.com",
  databaseAuthVariableOverride: null
});

// The app only has access to public data as defined in the Security Rules
var db = admin.database();
var ref = db.ref("/public_resource");
ref.once("value", function(snapshot) {
  console.log(snapshot.val());
});

Python

import firebase_admin
from firebase_admin import credentials
from firebase_admin import db

# Fetch the service account key JSON file contents
cred = credentials.Certificate('path/to/serviceAccountKey.json')

# Initialize the app with a None auth variable, limiting the server's access
firebase_admin.initialize_app(cred, {
    'databaseURL': 'https://databaseName.firebaseio.com',
    'databaseAuthVariableOverride': None
})

# The app only has access to public data as defined in the Security Rules
ref = db.reference('/public_resource')
print(ref.get())

Go

ctx := context.Background()
// Initialize the app with a nil auth variable, limiting the server's access
var nilMap map[string]interface{}
conf := &firebase.Config{
	DatabaseURL:  "https://databaseName.firebaseio.com",
	AuthOverride: &nilMap,
}

// Fetch the service account key JSON file contents
opt := option.WithCredentialsFile("path/to/serviceAccountKey.json")

app, err := firebase.NewApp(ctx, conf, opt)
if err != nil {
	log.Fatalln("Error initializing app:", err)
}

client, err := app.Database(ctx)
if err != nil {
	log.Fatalln("Error initializing database client:", err)
}

// The app only has access to public data as defined in the Security Rules
ref := client.NewRef("/some_resource")
var data map[string]interface{}
if err := ref.Get(ctx, &data); err != nil {
	log.Fatalln("Error reading from database:", err)
}
fmt.Println(data)

後續步驟

• 瞭解如何為 Realtime Database 建構資料。
• 跨多個資料庫執行個體擴充資料。
• 儲存資料。
• 擷取資料。
• 在 Firebase 主控台中查看資料庫。