fix(email): Fix SendGrid fallback integration

backend/src/core/config.ts

@@ -443,6 +443,14 @@ const config = convict({
       env: 'SMS_FALLBACK_SENDER_ID',
     },
   },
+  emailFallback: {
+    activate: {
+      doc:
+        'Switch to true to use the SendGrid fallback for emails. Ensure that the SMTP settings are properly configured as well.',
+      default: false,
+      env: 'EMAIL_FALLBACK_ACTIVATE',
+    },
+  },
 })
 
 // If mailFrom was not set in an env var, set it using the app_name

backend/src/core/loaders/express.loader.ts

@@ -91,6 +91,13 @@ const expressApp = ({ app }: { app: express.Application }): void => {
   app.use(requestTracerMiddleware)
 
   app.use(overrideContentTypeHeaderMiddleware)
+
+  // We need to parse the body as text specifically for SendGrid callbacks.
+  // This is to avoid stripping whitespace characters and messing with unicode encoding.
+  // This route affects SES callbacks as well, so we'll need to parse the text as JSON
+  // in the parseEvent() handle before parsing the SES event.
+  app.use('/v1/callback/email', bodyParser.text({ type: 'application/json' }))
+
   app.use(bodyParser.json())
   app.use(bodyParser.urlencoded({ extended: false }))
   // ref: https://expressjs.com/en/resources/middleware/cors.html#configuration-options

backend/src/core/services/mail-client.class.ts

@@ -2,6 +2,8 @@ import nodemailer from 'nodemailer'
 import directTransport from 'nodemailer-direct-transport'
 import { loggerWithLabel } from '@core/logger'
 import { MailToSend, MailCredentials } from '@core/interfaces'
+import config from '@core/config'
+
 const REFERENCE_ID_HEADER = 'X-SMTPAPI' // Case sensitive
 const logger = loggerWithLabel(module)
 
@@ -38,7 +40,9 @@ export default class MailClient {
   public sendMail(input: MailToSend): Promise<string | void> {
     return new Promise<string | void>((resolve, reject) => {
       const options = {
-        from: input.from,
+        from: config.get('emailFallback.activate')
+          ? config.get('mailFrom')
+          : input.from,
         to: input.recipients,
         subject: input.subject,
         replyTo: input.replyTo,

backend/src/email/middlewares/email.middleware.ts

@@ -113,6 +113,35 @@ const previewFirstMessage = async (
   }
 }
 
+/**
+ * Checks if the from address is custom and rejects it if necessary.
+ */
+const isCustomFromAddressAllowed = (
+  req: Request,
+  res: Response,
+  next: NextFunction
+): void => {
+  const { from } = req.body
+  const defaultEmail = config.get('mailFrom')
+
+  if (from === defaultEmail) {
+    next()
+    return
+  }
+
+  // We don't allow custom from address for the SendGrid fallback
+  // since they aren't DKIM-authenticated currently
+  if (config.get('emailFallback.activate')) {
+    res.status(503).json({
+      message:
+        'Unable to use a custom from address due to downtime. Please use the default from address instead.',
+    })
+    return
+  }
+
+  next()
+}
+
 /**
  * Checks that the from address is either the user's email or the default app email
  */
@@ -241,18 +270,20 @@ const getCustomFromAddress = async (
   res: Response,
   next: NextFunction
 ): Promise<Response | void> => {
-  const email =
-    req.session?.user?.email ||
-    (await AuthService.findUser(req.session?.user?.id))?.email
   const defaultEmail = config.get('mailFrom')
-  const result = []
+  const result = [defaultEmail]
 
-  try {
-    const fromAddress = await CustomDomainService.getCustomFromAddress(email)
-    if (fromAddress) result.push(fromAddress)
-    result.push(defaultEmail)
-  } catch (err) {
-    return next(err)
+  if (!config.get('emailFallback.activate')) {
+    const email =
+      req.session?.user?.email ||
+      (await AuthService.findUser(req.session?.user?.id))?.email
+    try {
+      const fromAddress = await CustomDomainService.getCustomFromAddress(email)
+      // Display the custom address first
+      if (fromAddress) result.unshift(fromAddress)
+    } catch (err) {
+      return next(err)
+    }
   }
 
   return res.status(200).json({ from: result })
@@ -333,6 +364,7 @@ export const EmailMiddleware = {
   storeFromAddress,
   getCustomFromAddress,
   existsFromAddress,
+  isCustomFromAddressAllowed,
   isFromAddressAccepted,
   sendValidationMessage,
   duplicateCampaign,

backend/src/email/routes/email-campaign.routes.ts

@@ -202,11 +202,14 @@ router.get('/', EmailMiddleware.getCampaignDetails)
  *           description: Forbidden as there is a job in progress
  *         "500":
  *           description: Internal Server Error
+ *         "503":
+ *           description: Service Unavailable. Try using the default from address instead.
  */
 router.put(
   '/template',
   celebrate(storeTemplateValidator),
   CampaignMiddleware.canEditCampaign,
+  EmailMiddleware.isCustomFromAddressAllowed,
   EmailMiddleware.isFromAddressAccepted,
   EmailMiddleware.existsFromAddress,
   EmailMiddleware.verifyFromAddress,

backend/src/email/routes/email-settings.routes.ts

@@ -43,11 +43,14 @@ const verifyValidator = {
  *          description: OK
  *        400:
  *          description: Bad Request (verification fails)
+ *        503:
+ *          description: Service Unavailable. Try using the default from address instead.
  *
  */
 router.post(
   '/from/verify',
   celebrate(verifyValidator),
+  EmailMiddleware.isCustomFromAddressAllowed,
   EmailMiddleware.isFromAddressAccepted,
   EmailMiddleware.verifyFromAddress,
   EmailMiddleware.sendValidationMessage,

backend/src/email/services/email-callback.service.ts

@@ -24,15 +24,16 @@ const isAuthenticated = (authHeader?: string): boolean => {
 }
 
 const parseEvent = async (req: Request): Promise<void> => {
+  const parsed = JSON.parse(req.body)
   let records: Promise<void>[] = []
   if (ses.isEvent(req)) {
     // body could be one record or an array of records, hence we concat
     const body: ses.SesRecord[] = []
-    const sesHttpEvent = body.concat(req.body)
+    const sesHttpEvent = body.concat(parsed)
     records = sesHttpEvent.map(ses.parseRecord)
   } else if (sendgrid.isEvent(req)) {
     // body is always an array
-    const sgEvent = req.body
+    const sgEvent = parsed
     records = sgEvent.map(sendgrid.parseRecord)
   } else {
     throw new Error('Unable to handle this event')

docs/configure/backend.md

@@ -109,13 +109,14 @@ Further reference: [Express-session documentation](https://www.npmjs.com/package
 
 If not set, `nodemailer-direct-transport` will be used (for testing locally)
 
-| Name       | Description                                                  |
-| ---------- | ------------------------------------------------------------ |
-| `SES_HOST` | Amazon SES SMTP endpoint.                                    |
-| `SES_PORT` | Amazon SES SMTP port, defaults to 465                        |
-| `SES_USER` | SMTP username                                                |
-| `SES_PASS` | SMTP password                                                |
-| `SES_FROM` | The email address that appears in the From field of an email |
+| Name                      | Description                                                                                                                |
+| ------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
+| `BACKEND_SES_HOST`        | Amazon SES SMTP endpoint.                                                                                                  |
+| `BACKEND_SES_PORT`        | Amazon SES SMTP port, defaults to 465                                                                                      |
+| `BACKEND_SES_USER`        | SMTP username                                                                                                              |
+| `BACKEND_SES_PASS`        | SMTP password                                                                                                              |
+| `BACKEND_SES_FROM`        | The email address that appears in the From field of an email                                                               |
+| `EMAIL_FALLBACK_ACTIVATE` | Switch to true to use the SendGrid fallback for all emails. Ensure that the SMTP settings are properly configured as well. |
 
 Further reference: [AWS SES documentation](https://docs.aws.amazon.com/ses/latest/DeveloperGuide/smtp-credentials.html)
 

docs/configure/worker.md

@@ -64,13 +64,14 @@ For testing locally, you may need to configure your `AWS_ACCESS_KEY_ID` and `AWS
 
 If not set, `nodemailer-direct-transport` will be used (for testing locally)
 
-| Name       | Description                                                  |
-| ---------- | ------------------------------------------------------------ |
-| `SES_HOST` | Amazon SES SMTP endpoint.                                    |
-| `SES_PORT` | Amazon SES SMTP port, defaults to 465                        |
-| `SES_USER` | SMTP username                                                |
-| `SES_PASS` | SMTP password                                                |
-| `SES_FROM` | The email address that appears in the From field of an email |
+| Name                      | Description                                                                                                                |
+| ------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
+| `WORKER_SES_HOST`         | Amazon SES SMTP endpoint.                                                                                                  |
+| `WORKER_SES_PORT`         | Amazon SES SMTP port, defaults to 465                                                                                      |
+| `WORKER_SES_USER`         | SMTP username                                                                                                              |
+| `WORKER_SES_PASS`         | SMTP password                                                                                                              |
+| `WORKER_SES_FROM`         | The email address that appears in the From field of an email                                                               |
+| `EMAIL_FALLBACK_ACTIVATE` | Switch to true to use the SendGrid fallback for all emails. Ensure that the SMTP settings are properly configured as well. |
 
 #### Sending smses
 

worker/src/core/config.ts

@@ -223,6 +223,14 @@ const config = convict({
       env: 'SMS_FALLBACK_SENDER_ID',
     },
   },
+  emailFallback: {
+    activate: {
+      doc:
+        'Switch to true to use the SendGrid fallback for emails. Ensure that the SMTP settings are properly configured as well.',
+      default: false,
+      env: 'EMAIL_FALLBACK_ACTIVATE',
+    },
+  },
 })
 
 // If mailFrom was not set in an env var, set it using the app_name

worker/src/email/services/mail-client.class.ts

@@ -2,6 +2,7 @@ import nodemailer from 'nodemailer'
 import directTransport from 'nodemailer-direct-transport'
 import { loggerWithLabel } from '@core/logger'
 import { MailToSend, MailCredentials } from '@email/interfaces'
+import config from '@core/config'
 
 const logger = loggerWithLabel(module)
 const REFERENCE_ID_HEADER = 'X-SMTPAPI' // Case sensitive
@@ -35,7 +36,9 @@ export default class MailClient {
   public sendMail(input: MailToSend): Promise<string | void> {
     return new Promise<string | void>((resolve, reject) => {
       const options = {
-        from: input.from,
+        from: config.get('emailFallback.activate')
+          ? config.get('mailFrom')
+          : input.from,
         to: input.recipients,
         subject: input.subject,
         replyTo: input.replyTo,