如果我這樣做，為什么Google Calendar API API NodeJS示例不起作用？

Question

基於該快速入門的NodeJS樣品（憑證與虛擬所替代） 在這里

以下是有效的代碼：

const fs = require('fs');
const mkdirp = require('mkdirp');
const readline = require('readline');
const {google} = require('googleapis');
const OAuth2Client = google.auth.OAuth2;
const SCOPES = ['https://www.googleapis.com/auth/calendar.readonly'];
const TOKEN_PATH = 'credentials.json';

// Load client secrets from a local file.
fs.readFile('client_secret.json', (err, content) => {
  if (err) return console.log('Error loading client secret file:', err);
  // Authorize a client with credentials, then call the Google Drive API.
  authorize(JSON.parse(content), listEvents);
});

/**
 * Create an OAuth2 client with the given credentials, and then execute the
 * given callback function.
 * @param {Object} credentials The authorization client credentials.
 * @param {function} callback The callback to call with the authorized client.
 */
function authorize(credentials, callback) {
  const {client_secret, client_id, redirect_uris} = credentials.web;
  const oAuth2Client = new OAuth2Client(client_id, client_secret, redirect_uris[0]);

  // Check if we have previously stored a token.
  fs.readFile(TOKEN_PATH, (err, token) => {
    if (err) return getAccessToken(oAuth2Client, callback);
    oAuth2Client.setCredentials(JSON.parse(token));

    // THIS WORKS IF ITS HERE AND PASSED IN CALLBACK
    let client = new OAuth2Client("484407463774-e7biatgmpns9jcpakr5g0sed8fab376u.apps.googleusercontent.com", "722_fI1u2abNM3tL-VbCuZfF", "http://localhost:1337/api/v1/oauthCallback");
    client.setCredentials({
      "access_token": "ya29.GluyBSUYvP_Gi4_SdJHabcJmXUjHnw34MfMBJ8tzROflqyR9dFMDOh_AYh9dmL4FSNDiva_nAcWYCM9m5jBwaL3pWfSm_wv0IybUUdebt66gDakdFXL0o8Mr-0Ge",
      "expiry_date": 1525551674971,
      "token_type": "Bearer",
      "refresh_token": "1/Ug8agC92PkJRXEDLP1inlHcAh4MBP1SLjNoylPJrmfg"
    });


    callback(client);
  });
}

/**
 * Get and store new token after prompting for user authorization, and then
 * execute the given callback with the authorized OAuth2 client.
 * @param {google.auth.OAuth2} oAuth2Client The OAuth2 client to get token for.
 * @param {getEventsCallback} callback The callback for the authorized client.
 */
 function getAccessToken(oAuth2Client, callback) {
  const authUrl = oAuth2Client.generateAuthUrl({
    access_type: 'offline',
    scope: SCOPES,
  });
  console.log('Authorize this app by visiting this url:', authUrl);
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
  });
  rl.question('Enter the code from that page here: ', (code) => {
    rl.close();
    oAuth2Client.getToken(code, (err, token) => {
      if (err) return callback(err);
      oAuth2Client.setCredentials(token);
      // Store the token to disk for later program executions
      fs.writeFile(TOKEN_PATH, JSON.stringify(token), (err) => {
        if (err) console.error(err);
        console.log('Token stored to', TOKEN_PATH);
      });
      callback(oAuth2Client).catch(console.error);
    });
  });
}

/**
 * Lists the next 10 events on the user's primary calendar.
 * @param {google.auth.OAuth2} auth An authorized OAuth2 client.
 */
function listEvents(auth) {

  const calendar = google.calendar({ version: 'v3', auth });
  calendar.events.list({
    calendarId: 'primary',
    timeMin: (new Date()).toISOString(),
    maxResults: 10,
    singleEvents: true,
    orderBy: 'startTime',
  }, (err, {data}) => {
    if (err) return console.log('The API returned an error: ' + err);
    const events = data.items;
    if (events.length) {
      console.log('Upcoming 10 events:');
      events.map((event, i) => {
        const start = event.start.dateTime || event.start.date;
        console.log(`${start} - ${event.summary}`);
      });
    } else {
      console.log('No upcoming events found.');
    }
  });


}

因此，在上面的代碼中，我們首先從憑據.json文件中找到憑據。 我只是為了方便在authorize()對它們進行了硬編碼

let client = new OAuth2Client("484407463774-e7biatgmpns9jcpakr5g0sed8fab376u.apps.googleusercontent.com", "722_fI1u2abNM3tL-VbCuZfF", "http://localhost:1337/api/v1/oauthCallback");
        client.setCredentials({
          "access_token": "ya29.GluyBSUYvP_Gi4_SdJHabcJmXUjHnw34MfMBJ8tzROflqyR9dFMDOh_AYh9dmL4FSNDiva_nAcWYCM9m5jBwaL3pWfSm_wv0IybUUdebt66gDakdFXL0o8Mr-0Ge",
          "expiry_date": 1525551674971,
          "token_type": "Bearer",
          "refresh_token": "1/Ug8agC92PkJRXEDLP1inlHcAh4MBP1SLjNoylPJrmfg"
        });

但是，如果我將上述行移動到listEvents()如下所示：

const fs = require('fs');
const mkdirp = require('mkdirp');
const readline = require('readline');
const {google} = require('googleapis');
const OAuth2Client = google.auth.OAuth2;
const SCOPES = ['https://www.googleapis.com/auth/calendar.readonly'];
const TOKEN_PATH = 'credentials.json';

// Load client secrets from a local file.
fs.readFile('client_secret.json', (err, content) => {
  if (err) return console.log('Error loading client secret file:', err);
  // Authorize a client with credentials, then call the Google Drive API.
  authorize(JSON.parse(content), listEvents);
});

/**
 * Create an OAuth2 client with the given credentials, and then execute the
 * given callback function.
 * @param {Object} credentials The authorization client credentials.
 * @param {function} callback The callback to call with the authorized client.
 */
function authorize(credentials, callback) {
  const {client_secret, client_id, redirect_uris} = credentials.web;
  const oAuth2Client = new OAuth2Client(client_id, client_secret, redirect_uris[0]);

  // Check if we have previously stored a token.
  fs.readFile(TOKEN_PATH, (err, token) => {
    if (err) return getAccessToken(oAuth2Client, callback);
    oAuth2Client.setCredentials(JSON.parse(token));


    callback(null);
  });
}

/**
 * Get and store new token after prompting for user authorization, and then
 * execute the given callback with the authorized OAuth2 client.
 * @param {google.auth.OAuth2} oAuth2Client The OAuth2 client to get token for.
 * @param {getEventsCallback} callback The callback for the authorized client.
 */
 function getAccessToken(oAuth2Client, callback) {
  const authUrl = oAuth2Client.generateAuthUrl({
    access_type: 'offline',
    scope: SCOPES,
  });
  console.log('Authorize this app by visiting this url:', authUrl);
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
  });
  rl.question('Enter the code from that page here: ', (code) => {
    rl.close();
    oAuth2Client.getToken(code, (err, token) => {
      if (err) return callback(err);
      oAuth2Client.setCredentials(token);
      // Store the token to disk for later program executions
      fs.writeFile(TOKEN_PATH, JSON.stringify(token), (err) => {
        if (err) console.error(err);
        console.log('Token stored to', TOKEN_PATH);
      });
      callback(oAuth2Client).catch(console.error);
    });
  });
}

/**
 * Lists the next 10 events on the user's primary calendar.
 * @param {google.auth.OAuth2} auth An authorized OAuth2 client.
 */
function listEvents(auth) {
 // THIS DOES NOT WORK 
 let client = new OAuth2Client("480557463774-e7biatgmpns9jcpakran0sed8f55376u.apps.googleusercontent.com", "722_fBsu2ECNM3tL-VbCuZfF", "http://localhost:1337/api/v1/oauthCallback");
  client.setCredentials({
    "access_token": "ya29.GluyBSUYvP_Gi4_SdJHsuPJmXUjHdd34MfMBJ8tzROflqyR9dFMDOh_AYh9dmL4FSNDiva_nAcWYCM9m5jBwaL3pWfSm_wv0IybUUORbt66gDakdFXL0o8Mr-0Ge",
    "expiry_date": 1525551674971,
    "token_type": "Bearer",
    "refresh_token": "1/Ug8MhC92ddJRXEDLP1inlHcAh4MBP1SLjNoylPJrmfg"
  });

  const calendar = google.calendar({ version: 'v3', client });
  calendar.events.list({
    calendarId: 'primary',
    timeMin: (new Date()).toISOString(),
    maxResults: 10,
    singleEvents: true,
    orderBy: 'startTime',
  }, (err, {data}) => {
    if (err) return console.log('The API returned an error: ' + err);
    const events = data.items;
    if (events.length) {
      console.log('Upcoming 10 events:');
      events.map((event, i) => {
        const start = event.start.dateTime || event.start.date;
        console.log(`${start} - ${event.summary}`);
      });
    } else {
      console.log('No upcoming events found.');
    }
  });


}

然后它不再起作用，並給出此錯誤：

(node:95252) UnhandledPromiseRejectionWarning: TypeError: Cannot destructure property `data` of 'undefined' or 'null'.
    at calendar.events.list (C:\Users\rahulserver\Desktop\gcalapinodejs\quickstart.js:87:6)
    at C:\Users\rahulserver\Desktop\gcalapinodejs\node_modules\google-auth-library\build\src\transporters.js:74:17
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
(node:95252) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside o
f an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:95252) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections tha
t are not handled will terminate the Node.js process with a non-zero exit code.

IMO我無論哪種情況都在做同樣的事情。 在第一種情況下，我將客戶端作為參數傳遞給回調。 第二，我將null傳遞給回調，並在回調本身中實例化oauth客戶端。 不知道第二種方法正在發生什么“神秘”事件，從而使代碼不再起作用。

Answer 1

您會遇到某種錯誤，這會使calendar.events.list()中的回調中的第二個arg變得undefined 。

請記住，此回調采用(err, {data}) => { ，因此，如果有錯誤，則不會有第二個arg。 但是，您仍在嘗試對其進行重組，因此會出現錯誤。

簡單的解決方法是應用默認參數。 如果發生錯誤，這將使其使用空對象：

(err, { data } = {}) => {

或者，您可以在錯誤檢查后對其進行重構。 我個人是默認參數的粉絲。

進行更改后，您將能夠看到錯誤所在。 希望該消息將使其余問題更容易解決。

Answer 2

好吧，我想通了。

而不是const calendar = google.calendar({ version: 'v3', client });

應該是const calendar = google.calendar({ version: 'v3', auth: client });

因此es6對象速記語法有時會令人困惑！