Trigger Email from Firestore

Author: Firebase (https://firebase.google.com)

Description: Composes and sends an email based on the contents of a document written to a specified Cloud Firestore collection.

Details: Use this extension to render and send emails that contain the information from documents added to a specified Cloud Firestore collection.

Adding a document triggers this extension to send an email built from the document's fields. The document's top-level fields specify the email sender and recipients, including to, cc, and bcc options (each supporting UIDs). The document's message field specifies the other email elements, like subject line and email body (either plaintext or HTML)

Here's a basic example document write that would trigger this extension:

admin.firestore().collection('mail').add({
  to: '[email protected]',
  message: {
    subject: 'Hello from Firebase!',
    html: 'This is an <code>HTML</code> email body.',
  },
})

You can also optionally configure this extension to render emails using Handlebar templates. Each template is a document stored in a Cloud Firestore collection.

When you configure this extension, you'll need to supply your SMTP credentials for mail delivery. Note that this extension is for use with bulk email service providers, like SendGrid, Mailgun, etc.

Setup Google App Passwords

Google no longer allows Gmail users to use their own passwords to authorize third-party apps and services. Instead, you have to use the Sign in with App Passwords service to generate a special password for each app you want to authorize. To do so:

1. Go to your Google Account.
2. Select Security.
3. Under "Signing in to Google," select App Passwords. You may need to sign in. If you don’t have this option, it might be because:
   1. 2-Step Verification is not set up for your account.
   2. 2-Step Verification is only set up for security keys.
   3. Your account is through work, school, or other organization.
   4. You turned on Advanced Protection.
4. At the bottom, choose Select app and choose Other option and then write the name of the app password (e.g. Firebase Trigger Email from Firestore Extension) and click Generate.
5. Follow the instructions to enter the App Password. The App Password is the 16-character code in the yellow bar on your device.
6. Tap Done.

Now you can use your Google username with the generated password to authorize the extension.

Additional setup

Before installing this extension, make sure that you've set up a Cloud Firestore database in your Firebase project.

Billing

To install an extension, your project must be on the Blaze (pay as you go) plan

• This extension uses other Firebase and Google Cloud Platform services, which have associated charges if you exceed the service’s no-cost tier:
  • Cloud Firestore
  • Cloud Functions (Node.js 10+ runtime. See FAQs)

Usage of this extension also requires you to have SMTP credentials for mail delivery. You are responsible for any associated costs with your usage of your SMTP provider.

Further reading & resources

You can find more information about this extension in the following articles:

• Sending Emails Using Firestore And Firebase Extensions

Configuration Parameters:

• Cloud Functions location: Where do you want to deploy the functions created for this extension? You usually want a location close to your database. For help selecting a location, refer to the location selection guide.

• SMTP connection URI: A URI representing an SMTP server this extension can use to deliver email. Note that port 25 is blocked by Google Cloud Platform, so we recommend using port 587 for SMTP connections. If you're using the SMTPS protocol, we recommend using port 465. In order to keep passwords secure, it is recommended to omit the password from the connection string while using the SMTP Password field for entering secrets and passwords. Passwords and secrets should now be included in SMTP password field. Secure format: smtps://[email protected]@smtp.gmail.com:465 (username only) smtps://smtp.gmail.com:465 (No username and password) Backwards Compatible (less secure): smtps://[email protected]:[email protected]:465. (username and password)

• SMTP password: User password for the SMTP server

• Email documents collection: What is the path to the collection that contains the documents used to build and send the emails?

• Default FROM address: The email address to use as the sender's address (if it's not specified in the added email document). You can optionally include a name with the email address (Friendly Firebaser <[email protected]>).

• Default REPLY-TO address: The email address to use as the reply-to address (if it's not specified in the added email document).

• Users collection: A collection of documents keyed by user UID. If the toUids, ccUids, and/or bccUids recipient options are used in the added email document, this extension delivers email to the email field based on lookups in this collection.

• Templates collection: A collection of email templates keyed by name. This extension can render an email using a Handlebar template, if the template is specified in the added email document.

• Firestore TTL type: Do you want the firestore records to be marked with an expireAt field for a TTL policy? If "Never" is selected then no expireAt field will be added. Otherwise you may specify the unit of time specified by the TTL_EXPIRE_VALUE parameter. Defaults to "Never".

• Firestore TTL value: In the units specified by TTL_EXPIRE_TYPE, how long do you want records to be ineligible for deletion by a TTL policy? This parameter requires the Firestore TTL type parameter to be set to a value other than Never. For example, if Firestore TTL type is set to Day then setting this parameter to 1 will specify a TTL of 1 day.

Cloud Functions:

• processQueue: Processes document changes in the specified Cloud Firestore collection, delivers emails, and updates the document with delivery status information.

Access Required:

This extension will operate with the following project IAM roles:

• datastore.user (Reason: Allows this extension to access Cloud Firestore to read and process added email documents.)