使用 Google Cloud PubSub 时不断收到“向 Cloud PubSub 发送测试消息时出错...”

我正在尝试将 Google 的推送 PubSub 设置到我的服务器以接收 Gmail 推送通知。

我得到以下范围：

• https://mail.google.com/ https://mail.google.com/
• https://www.googleapis.com/auth/cloud-platform https://www.googleapis.com/auth/cloud-platform
• https://www.googleapis.com/auth/pubsub https://www.googleapis.com/auth/pubsub
• https://www.googleapis.com/auth/gmail.modify https://www.googleapis.com/auth/gmail.modify
• https://www.googleapis.com/auth/gmail.readonly https://www.googleapis.com/auth/gmail.readonly

它可以创建一个主题、订阅该主题、授予对该主题的 Gmail API 的访问权限，但当我尝试查看我的收件箱时，它会失败。我已经遵循了这个指南：https://developers.google.com/gmail/api/guides/push https://developers.google.com/gmail/api/guides/push这是我用来执行上述步骤的代码：

var rp = require('request-promise');

// Step 1. Create a topic
rp({
   url: 'https://pubsub.googleapis.com/v1/projects/projectId/topics/mailSync',
   method: 'PUT',
   headers: {
     Authorization: 'Bearer accessToken'
   }
 }).then(function(response) {
   console.log(response);
   res.send(response);
 })
 .catch(function(error) {
   console.log(error.message);
   res.send(error.message);
 });

// Step 2. Create a subscription:
rp({
   url: 'https://pubsub.googleapis.com/v1/projects/projectId/subscriptions/mailSync',
   method: 'PUT',
   headers: {
     Authorization: 'Bearer accessToken'
   },
   json: {
     topic: 'projects/projectId/topics/mailSync',
     pushConfig: {
       pushEndpoint: 'https://developers.example.com/mailSyncHandler'
     }
   }
 }).then(function(response) {
   console.log(response);
   res.send(response);
 })
 .catch(function(err) {
   console.error(err);
   res.status(err.statusCode).send(err.error.error.message);
 });

// Step 3. Grant the Gmail API publish rights on our topic
rp({
   url: "https://pubsub.googleapis.com/v1beta2/projects/projectId/topics/mailSync:setIamPolicy",
   method: 'POST',
   headers: {
     Authorization: 'Bearer accessToken'
   },
   data: {
     policy: {
       bindings: [{
         role: "roles/pubsub.publisher",
         members: ["serviceAccount:[email protected] /cdn-cgi/l/email-protection"]
       }]
     }
   },
   json: true
 }).then(function(response) {
   console.log(response);
   res.send(response);
 })
 .catch(function(error) {
   console.log(error.message);
   res.send(error.message);
 });

// Step 4. Watch my Inbox
rp({
  url: "https://www.googleapis.com/gmail/v1/users/me/watch",
  method: "POST",
  headers: {
    Authorization: 'Bearer accessToken'
  },
  json: {
    topicName: "projects/projectId/topics/mailSync",
    labelIds: ["INBOX"]
  }
}).then(function(response) {
  console.log(response);
  res.send(response);
})
.catch(function(error) {
  console.error(error);
  res.send(error.message);
});

弄清楚为什么我收到错误，这是因为我没有在步骤 4 中以 JSON 形式发送数据。

步骤 4 中的正确代码是（请注意，我正在使用json:代替body:第 8 行）：

// Step 4. Watch my Inbox
rp({
  url: "https://www.googleapis.com/gmail/v1/users/me/watch",
  method: "POST",
  headers: {
    Authorization: 'Bearer accessToken'
  },
  json: {     <-----
    topicName: "projects/projectId/topics/mailSync",
    labelIds: ["INBOX"]
  }
}).then(function(response) {
  console.log(response);
  res.send(response);
})
.catch(function(error) {
  console.error(error);
  res.send(error.message);
});