如何刷新youtube-data-api v3的访问令牌

Question

我使用youtube数据api的v3作为我的服务器。到目前为止，我能够通过从重定向获得代码来创建令牌。

                oauth2Client.getToken(req.query.code, function(err, token) {
                    if (err) {
                      console.log('Error while trying to retrieve access token', err);
                      return;
                    }
                    oauth2Client.credentials = token;
                    storeToken(token);
                    res.redirect("/channel");
                  });

我在本地存储这个令牌，但我有以下几个问题；

1. 如何检查请求即将发出时此令牌是否有效？
2. 如何通过使用刷新令牌获得新令牌(如果当前所拥有的令牌已过期)？

Answer 1

了解令牌是否有效的最佳方法是使用它。在访问令牌的情况下，只需使用它进行调用即可。在刷新令牌的情况下，答案是相同的，使用它创建一个新的访问令牌。

node.js客户端库应该为您处理访问令牌的所有刷新。

第一次运行此代码时，将在TOKEN_PATH中创建包含用户同意的文件，这是刷新令牌。如果文件存在，它将用于根据需要创建一个新的访问令牌。

const fs = require('fs');
const readline = require('readline');
const {google} = require('googleapis');

// If modifying these scopes, delete token.json.
const SCOPES = ['https://www.googleapis.com/auth/youtube'];
// The file token.json stores the user's access and refresh tokens, and is
// created automatically when the authorization flow completes for the first
// time.
const TOKEN_PATH = 'token.json';

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

/**
 * 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.installed;
  const oAuth2Client = new google.auth.OAuth2(
      client_id, client_secret, redirect_uris[0]);

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

/**
 * 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 getNewToken(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 console.error('Error retrieving access token', err);
      oAuth2Client.setCredentials(token);
      // Store the token to disk for later program executions
      fs.writeFile(TOKEN_PATH, JSON.stringify(token), (err) => {
        if (err) return console.error(err);
        console.log('Token stored to', TOKEN_PATH);
      });
      callback(oAuth2Client);
    });
  });
}