Cloud Functions for Firebase onWrite 触发器：snapshot.val 不是函数

Question

我在同一个 index.js 文件中创建了几个函数，即 sendEmail、sendEmailByDbStatusChange 和 sendEmailConfirmation。

sendEmail- 通过 HTTP/API 调用

sendEmailByDbStatusChange - 在值更改时监听 DB，但操作是硬编码的

sendEmailConfirmation- 值更改时列出到数据库，操作以快照为准。

以下是我的代码：

const functions = require('firebase-functions');
const nodemailer = require('nodemailer');
const gmailEmail = functions.config().gmail.email;
const gmailPassword = functions.config().gmail.password;
const mailTransport = nodemailer.createTransport({
  service: 'gmail',
  auth: {
    user: gmailEmail,
    pass: gmailPassword,
  },
});

// Sends an email confirmation when a user changes his mailing list subscription.
exports.sendEmail = functions.https.onRequest((req, res) => {
  if (req.body.subject === undefined || req.body.recipient === undefined) {
    // This is an error case, as "message" is required.
    //res.status(400).send('subject/body/recipient is missing!');
    return false
  } else {
    const mailSubject = req.body.subject;
    const mailHtmlBody = req.body.htmlBody;
    const mailRecipient = req.body.recipient;



    const mailOptions = {
      from: '"Food Ninja." <foodninjaapp@gmail.com>',
      to: mailRecipient,
      subject: mailSubject,
      html: mailHtmlBody
    };

    //res.status(200).send('Success: ' + mailSubject + ' to ' + mailRecipient);

    return mailTransport.sendMail(mailOptions)
      .then(() => {
        console.log(`${mailSubject}subscription confirmation email sent to: `, mailRecipient)
        return res.status(200).send('Success: ' + mailSubject + ' to ' + mailRecipient)
      })
      .catch((error) => console.error('There was an error while sending the email:', error));
  }
});

exports.sendEmailByDbStatusChange = functions.database.ref('/users/{uid}').onWrite((event) => {
  //const snapshot = event.data;
  //const val = snapshot.val();

  //if (!snapshot.changed('subscribedToMailingList')) {
  //  return null;
  //}

  const mailSubject = 'Sending email with Cloud Function - by DB onWrite Trigger';
  const mailHtmlBody = '<h1>Hello Jerry</h1><p>If you receiving this means that you have successfully deployed a customized firebase function</p><p>Be Happy!<br><br>Food Ninja Team</p>';
  const mailRecipient = 'admin@phd.com.my';

  const mailOptions = {
    from: '"Food Ninja." <foodninjaapp@gmail.com>',
    to: mailRecipient,
    subject: mailSubject,
    html: mailHtmlBody
  };

  //const subscribed = val.subscribedToMailingList;

  // Building Email message.
  //mailOptions.subject = subscribed ? 'Thanks and Welcome!' : 'Sad to see you go :`(';
  //mailOptions.text = subscribed ? 'Thanks you for subscribing to our newsletter. You will receive our next weekly newsletter.' : 'I hereby confirm that I will stop sending you the newsletter.';

  return mailTransport.sendMail(mailOptions)
    .then(() =>
      console.log(`${mailSubject}subscription confirmation email sent to: `, mailRecipient)
      //return res.status(200).send('Success: ' + mailSubject + ' to ' + mailRecipient)
    )
    .catch((error) => console.error('There was an error while sending the email:', error));
});

exports.sendEmailConfirmation = functions.database.ref('/users/{uid}').onWrite((event2) => {
  console.log(event2)
  console.log(event2.val())
  console.log(event2.val().data)
  console.log(event2.data)
  console.log(event2.data.val())
  const snapshot = event2.data;
  console.log(snapshot)
  const val = snapshot.val();
  console.log(val)

  if (!snapshot.changed('subscribedToMailingList')) {
    return null;
  }

  const mailOptions = {
    from: '"Spammy Corp." <noreply@firebase.com>',
    to: val.email,
  };

  const subscribed = val.subscribedToMailingList;

  // Building Email message.
  mailOptions.subject = subscribed ? 'Thanks and Welcome!' : 'Sad to see you go :`(';
  mailOptions.text = subscribed ? 'Thanks you for subscribing to our newsletter. You will receive our next weekly newsletter.' : 'I hereby confirm that I will stop sending you the newsletter.';

  return mailTransport.sendMail(mailOptions)
    .then(() => console.log(`New ${subscribed ? '' : 'un'}subscription confirmation email sent to:`, val.email))
    .catch((error) => console.error('There was an error while sending the email:', error));
});

我的问题是，在我将代码部署到firebase函数后，控制台显示sendEmailConfirmation由于event2.val不是函数而无法顺利执行。

我当前的代码结合了我的自定义代码和原始代码，sendEmailConfirmation 是原始代码。当独立运行原始代码时，它确实可以工作（原始代码是event，而不是快照的event2）。

请指教。

Answer 1

您似乎已更新到 Cloud Functions 的 Firebase SDK v1.0，但没有升级您的代码以匹配。

整个过程在this documentation page中解释。现在你正被changes in database triggers 击中，这表明：

事件数据现在是 DataSnapshot

在早期版本中，event.data 是 DeltaSnapshot；现在在 v 1.0 中，它是 DataSnapshot。

对于onWrite 和onUpdate 事件，data 参数具有before 和after 字段。其中每一个都是DataSnapshot，与admin.database.DataSnapshot 中可用的方法相同。例如：

之前 (

exports.dbWrite = functions.database.ref('/path').onWrite((event) => {
  const beforeData = event.data.previous.val(); // data before the write
  const afterData = event.data.val(); // data after the write
});

现在 (v1.0.0)

exports.dbWrite = functions.database.ref('/path').onWrite((change, context) => {
  const beforeData = change.before.val(); // data before the write
  const afterData = change.after.val(); // data after the write
});

根据该示例，您将需要以下内容：

exports.sendEmailConfirmation = functions.database.ref('/users/{uid}').onWrite((change, context) => {
  const snapshot = change.after;
  const val = snapshot.val();
  console.log(val)

  if (!snapshot.changed('subscribedToMailingList')) {
    return null;
  }

  const mailOptions = {
    from: '"Spammy Corp." <noreply@firebase.com>',
    to: val.email,
  };

  const subscribed = val.subscribedToMailingList;

  // Building Email message.
  mailOptions.subject = subscribed ? 'Thanks and Welcome!' : 'Sad to see you go :`(';
  mailOptions.text = subscribed ? 'Thanks you for subscribing to our newsletter. You will receive our next weekly newsletter.' : 'I hereby confirm that I will stop sending you the newsletter.';

  return mailTransport.sendMail(mailOptions)
    .then(() => console.log(`New ${subscribed ? '' : 'un'}subscription confirmation email sent to:`, val.email))
    .catch((error) => console.error('There was an error while sending the email:', error));
});

Answer 2

从 firebase-functions 模块的 1.0.0 版开始，数据库 onWrite 事件现在传递 Change 对象而不是 DataSnapshot 对象作为第一个参数。您可以在documentation 中了解 1.0.0 中的所有重大更改。您应该使用此更改对象来选择是否要在调用它的更改之前或之后检查数据库的内容。