運用 Cloud Functions 擴充遠端設定功能

您可以觸發函式，回應 Remote Config 事件，包括發布新設定版本或回溯至舊版本。本指南說明如何建立 Remote Config 背景函式，以便執行兩個範本版本的差異比較。

觸發 Remote Config 函式

如要觸發 Remote Config 函式，請先匯入必要的模組：

Node.js

 // The Cloud Functions for Firebase SDK to set up triggers and logging.
const {onConfigUpdated} = require("firebase-functions/v2/remoteConfig");
const logger = require("firebase-functions/logger");
// The Firebase Admin SDK to obtain access tokens.
const admin = require("firebase-admin");
const app = admin.initializeApp();
const fetch = require("node-fetch");
const jsonDiff = require("json-diff");index.js

Python

 # The Cloud Functions for Firebase SDK to set up triggers and logging.
from firebase_functions import remote_config_fn

# The Firebase Admin SDK to obtain access tokens.
import firebase_admin

app = firebase_admin.initialize_app()

import deepdiff
import requestsmain.py

接著，定義更新事件的處理常式。傳遞至此函式的事件物件包含範本更新的中繼資料，例如新版本號碼和更新時間。您也可以擷取更新內容的使用者電子郵件地址、名稱和圖片 (如有)。

以下是 Remote Config 函式的範例，可記錄每個更新版本與其取代的版本之間的差異。這個函式會檢查範本物件的版本號碼欄位，並擷取目前 (新更新) 版本，以及比該版本低一個號碼的版本：

Node.js

 exports.showconfigdiff = onConfigUpdated(async (event) => {
  try {
    // Obtain the access token from the Admin SDK
    const accessTokenObj = await admin.credential.applicationDefault()
        .getAccessToken();
    const accessToken = accessTokenObj.access_token;

    // Get the version number from the event object
    const remoteConfigApi = "https://firebaseremoteconfig.googleapis.com/v1/" +
        `projects/${app.options.projectId}/remoteConfig`;
    const currentVersion = event.data.versionNumber;
    const prevVersion = currentVersion - 1;
    const templatePromises = [];
    templatePromises.push(fetch(
        remoteConfigApi,
        {
          method: "POST",
          body: new URLSearchParams([["versionNumber", currentVersion + ""]]),
          headers: {Authorization: "Bearer " + accessToken},
        },
    ));
    templatePromises.push(fetch(
        remoteConfigApi,
        {
          method: "POST",
          body: new URLSearchParams([["versionNumber", prevVersion + ""]]),
          headers: {Authorization: "Bearer " + accessToken},
        },
    ));

    // Get the templates
    const responses = await Promise.all(templatePromises);
    const results = responses.map((r) => r.json());
    const currentTemplate = results[0];
    const previousTemplate = results[1];
    // Figure out the differences of the templates
    const diff = jsonDiff.diffString(previousTemplate, currentTemplate);
    // Log the difference
    logger.log(diff);
  } catch (error) {
    logger.error(error);
  }
});index.js

這個範例會使用 json-diff 和 request-promise 模組建立差異，並建構要求以取得範本物件。

Python

 @remote_config_fn.on_config_updated()
def showconfigdiff(event: remote_config_fn.CloudEvent[remote_config_fn.ConfigUpdateData]) -> None:
    """Log the diff of the most recent Remote Config template change."""

    # Obtain an access token from the Admin SDK
    access_token = app.credential.get_access_token().access_token

    # Get the version number from the event object
    current_version = int(event.data.version_number)

    # Figure out the differences between templates
    remote_config_api = ("https://firebaseremoteconfig.googleapis.com/v1/"
                         f"projects/{app.project_id}/remoteConfig")
    current_template = requests.get(remote_config_api,
                                    params={"versionNumber": current_version},
                                    headers={"Authorization": f"Bearer {access_token}"})
    previous_template = requests.get(remote_config_api,
                                     params={"versionNumber": current_version - 1},
                                     headers={"Authorization": f"Bearer {access_token}"})
    diff = deepdiff.DeepDiff(previous_template, current_template)

    # Log the difference
    print(diff.pretty())main.py

這個範例使用 deepdiff 建立差異，並使用 requests 建構及傳送要求，以便取得範本物件。