无法使用谷歌 API 获取电子邮件的消息内容

如何解决无法使用谷歌 API 获取电子邮件的消息内容

我正在尝试编写一些代码，以便使用 Google API 检索电子邮件。我按照此处提供的文档：https://developers.google.com/gmail/api/reference/rest/v1/users.messages/get?apix_params=%7B%22userId%22%3A%22prashanthpillay2%40gmail.com%22%2C%22id%22%3A%22176d95971a2ffce1%22%7D 来实现我的 showMessageContent 函数并使用此处找到的快速入门示例：https://developers.google.com/gmail/api/quickstart/nodejs?authuser=1，但是当我执行代码时，我只显示了消息 ID，而与实际情况无关信息。任何帮助都会很棒，我对这些东西很陌生。

我的 index.js 文件的完整代码：

const fs = require('fs');
const readline = require('readline');
const {google} = require('googleapis');
let messageArr = [];

// If modifying these scopes,delete token.json.
const SCOPES = ['https://www.googleapis.com/auth/gmail.readonly'];
// 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('client_secret.json',(err,content) => {
  if (err) return console.log('Error loading client secret file:',err);
  // Authorize a client with credentials,then call the Gmail API.
  authorize(JSON.parse(content),listMessages);
});

/**
 * 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,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,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);
    });
  });
}

async function listMessages(auth) {
  const gmail = google.gmail({version: 'v1',auth});
  gmail.users.messages.list({
    userId: 'me',maxResults: 1
  },res) => {
    if (err) return console.log('The API returned an error: ' + err);
    const messages = res.data.messages;
    if (messages) {
      console.log('Messages:');
      let i=0;
      messages.forEach((message) => {
          messageArr[i] = message.id;
          console.log(messageArr[i]);
          i++;
      
      });
    } else {
      console.log('No messages found.');
    }

    
  }); 
  
  setTimeout(() => 
  {console.log(gmail.users.messages.get(
    {
      userId: 'me',id: '176daac2fedbf7f9'
    },res) => {
      if (err) return console.log('The API returned an error: ' + err);
      else{
        return res;
      }
      
    })
  );

  

  },3000);

}

问题函数：

    async function listMessages(auth) {
  const gmail = google.gmail({version: 'v1',3000);

}

运行结果在附图中

当 setTimeout 中的回调运行时，它导致结果未定义，这对我来说没有意义，因为我手动将正确的 ID 传递给 gmail.users.messages.get()。