通过 Cloud Functions 访问 Gmail API

Question

我正在尝试构建一个响应 gmail pubsub 消息的电子邮件解析器。我目前能够接收和解析 pubsub 消息并提取 historyId，但我无法验证我对 gmail api 的请求。这是我到目前为止所拥有的：

  //function defined outside the scope of the main function
  //used to create auth client
  function getAuthClient(event, callback) {
    var GoogleAuth = require('google-auth-library');

    var authFactory = new GoogleAuth();

    authFactory.getApplicationDefault(function (err, authClient) {
     if (err) {
       console.log('Unable to get application default credentials.');
       callback(err);
       return;
     }

     // Create the oAuth scopes you need
     if (authClient.createScopedRequired && authClient.createScopedRequired()) {
    console.log('creating scoped client');
      authClient = authClient.createScoped([
          'https://mail.google.com/'
      ]);
    }
   callback(null, authClient);
  });
}

exports.gmailParser = function gmailParser (event, callback) {
 var path = require('path');
 var base64 = require('base-64');

 // Set your service account key file into the environment for the auth lib 
to pick up
 process.env['GOOGLE_APPLICATION_CREDENTIALS'] = path.resolve(__dirname, 
'auth_credentials.json');
 console.log(process.env['GOOGLE_APPLICATION_CREDENTIALS']);


 console.log(__dirname);

 //parse pubsub message
 var pubsubMessage = event.data;
 var baseMessage = pubsubMessage.data;
 var decodedMessage = base64.decode(baseMessage);
 var messageJSON = JSON.parse(decodedMessage);

 // Extract emailAddress and historyId from gmail pubsub message
 var historyId = messageJSON.historyId;
 var email = messageJSON.emailAddress;

 getAuthClient(null, function(err, authClient) {

   //import necessary libraries
   var google = require('googleapis');
   var gmail = google.gmail('v1');

   if(err) {
     callback(err);
   }

  // Construct a params object
  var params = {
    userId: email,
    startHistoryId: historyId
 };


//Attempt to call gmail api. This is where the error occurs.
gmail.users.history.list(params, function(error, response) {
  if (error) {  
    console.log('Encountered error', error);
    callback(error);
  } else {
    console.log('Response', response);
    callback(response);
  }
});
 });
};

代码运行成功，但出现以下错误：

"Error: Login Required
at Request._callback (/user_code/node_modules/googleapis/node_modules/google-auth-library/lib/transporters.js:85:15)
at Request.self.callback (/user_code/node_modules/googleapis/node_modules/request/request.js:188:22)
at emitTwo (events.js:106:13)
at Request.emit (events.js:191:7)
at Request.<anonymous> (/user_code/node_modules/googleapis/node_modules/request/request.js:1171:10)
at emitOne (events.js:96:13)
at Request.emit (events.js:188:7)
at IncomingMessage.<anonymous> (/user_code/node_modules/googleapis/node_modules/request/request.js:1091:12)
at IncomingMessage.g (events.js:291:16)
at emitNone (events.js:91:20)"   

我尝试将 authClient 添加到 param 对象，但它返回“错误请求”错误。我已经尝试更改导入的顺序，创建了新的凭据，但我无法到达任何地方。如果有人有任何指点，将不胜感激。

Answer 1

这篇博文可能会有所帮助。它包含有关使用 nodejs 和 Cloud Functions 获取 OAuth 令牌的详细信息。我试过了，效果很好。

https://cloud.google.com/blog/products/application-development/adding-custom-intelligence-to-gmail-with-serverless-on-gcp

代码：https://github.com/GoogleCloudPlatform/cloud-functions-gmail-nodejs

以下代码 sn-p 请求 OAuth 2.0 授权码

exports.oauth2init = (req, res) => {
  // Define OAuth2 scopes
  const scopes = [
    'https://www.googleapis.com/auth/gmail.modify'
  ];

  // Generate + redirect to OAuth2 consent form URL
  const authUrl = oauth.client.generateAuthUrl({
    access_type: 'offline',
    scope: scopes,
    prompt: 'consent' // Required in order to receive a refresh token every time
  });
  return res.redirect(authUrl);
};

以下代码 sn -p 从 OAuth 授权码中获取访问令牌

exports.oauth2callback = (req, res) => {
  // Get authorization code from request
  const code = req.query.code;

  // OAuth2: Exchange authorization code for access token
  return new Promise((resolve, reject) => {
    oauth.client.getToken(code, (err, token) =>
      (err ? reject(err) : resolve(token))
    );
  })