🐛 Fixed newsletter not sending if locale is invalid (#21573)

ref https://github.com/moment/luxon/blob/master/docs/intl.md

- We noticed the following error trace: RangeError: Incorrect locale
information provided
at BatchSendingService.retryDb
(/home/ghost/node_modules/@tryghost/email-service/lib/BatchSendingService.js:639:32)
    at new DateTimeFormat (<anonymous>)
at getCachedDTF
(/home/ghost/node_modules/luxon/build/node/luxon.js:621:11)
at new PolyDateFormatter
(/home/ghost/node_modules/luxon/build/node/luxon.js:842:16)
at Locale.dtFormatter
(/home/ghost/node_modules/luxon/build/node/luxon.js:1066:12)
at Formatter.dtFormatter
(/home/ghost/node_modules/luxon/build/node/luxon.js:2274:21)
at Formatter.formatDateTime
(/home/ghost/node_modules/luxon/build/node/luxon.js:2280:17)
at DateTime.toLocaleString
(/home/ghost/node_modules/luxon/build/node/luxon.js:6893:78)
at formatDateLong
(/home/ghost/node_modules/@tryghost/email-service/lib/EmailRenderer.js:45:74)
at Object.getValue
(/home/ghost/node_modules/@tryghost/email-service/lib/EmailRenderer.js:683:47)
at
/home/ghost/node_modules/@tryghost/email-service/lib/SendingService.js:158:36
    at Array.map (<anonymous>)
at
/home/ghost/node_modules/@tryghost/email-service/lib/SendingService.js:154:54
    at Array.map (<anonymous>)
at SendingService.buildRecipients
(/home/ghost/node_modules/@tryghost/email-service/lib/SendingService.js:151:24)
at SendingService.send
(/home/ghost/node_modules/@tryghost/email-service/lib/SendingService.js:127:33)
at response.retryDb
(/home/ghost/node_modules/@tryghost/email-service/lib/BatchSendingService.js:451:51)
- This is due to the locale being user-input - it can be set to any
string.
- In our email sending code we pass the string to luxon to format dates,
which errors if the locale is not valid according it Intl.
- This fix ensures that the locale is valid before passing it to luxon,
falling back to en-gb if the locale is not valid

ghost/email-service/lib/EmailRenderer.js

@@ -12,6 +12,8 @@ const {EmailAddressParser} = require('@tryghost/email-addresses');
 const {registerHelpers} = require('./helpers/register-helpers');
 const crypto = require('crypto');
 
+const DEFAULT_LOCALE = 'en-gb';
+
 // Wrapper function so that i18next-parser can find these strings
 const t = (x) => {
     return x;
@@ -38,10 +40,17 @@ function escapeHtml(unsafe) {
         .replace(/'/g, ''');
 }
 
-function formatDateLong(date, timezone, locale = 'en-gb') {
+function isValidLocale(locale) {
-    if (locale === 'en') { 
+    try {
-        locale = 'en-gb'; 
+        // Attempt to create a DateTimeFormat with the locale
+        new Intl.DateTimeFormat(locale);
+        return true; // No error means it's a valid locale
+    } catch (e) {
+        return false; // RangeError means invalid locale
     }
+}
+
+function formatDateLong(date, timezone, locale = DEFAULT_LOCALE) {
     return DateTime.fromJSDate(date).setZone(timezone).setLocale(locale).toLocaleString({
         year: 'numeric',
         month: 'long',
@@ -216,6 +225,21 @@ class EmailRenderer {
         };
     }
 
+    // Locale is user-input, so we need to ensure it's valid
+    #getValidLocale() {
+        let locale = this.#settingsCache.get('locale') || DEFAULT_LOCALE;
+
+        // Remove any trailing whitespace
+        locale = locale.trim();
+
+        // If the locale is just "en", or is not valid, revert to default
+        if (locale === 'en' || !isValidLocale(locale)) {
+            locale = DEFAULT_LOCALE;
+        }
+
+        return locale;
+    }
+
     getFromAddress(post, newsletter) {
         // Clean from address to ensure DMARC alignment
         const addresses = this.#emailAddressService.getAddress({
@@ -562,7 +586,7 @@ class EmailRenderer {
      */
     getMemberStatusText(member) {
         const t = this.#t;
-        const locale = this.#settingsCache.get('locale');
+        const locale = this.#getValidLocale();
 
         if (member.status === 'free') {
             // Not really used, but as a backup
@@ -625,7 +649,7 @@ class EmailRenderer {
      */
     buildReplacementDefinitions({html, newsletterUuid}) {
         const t = this.#t; // es-lint-disable-line no-shadow
-        const locale = this.#settingsCache.get('locale');
+        const locale = this.#getValidLocale();
 
         const baseDefinitions = [
             {

ghost/email-service/test/email-renderer.test.js

@@ -399,6 +399,7 @@ describe('Email renderer', function () {
             assert.equal(replacements[0].id, 'created_at');
             assert.equal(replacements[0].getValue(member), '13 March 2023');
         });
+
         it('handles dates when the locale is fr', function () {
             emailRenderer = new EmailRenderer({
                 urlUtils: {
@@ -427,6 +428,7 @@ describe('Email renderer', function () {
             assert.equal(replacements[0].id, 'created_at');
             assert.equal(replacements[0].getValue(member), '13 mars 2023');
         });
+
         it('handles dates when the locale is en (US)', function () {
             emailRenderer = new EmailRenderer({
                 urlUtils: {
@@ -455,6 +457,65 @@ describe('Email renderer', function () {
             assert.equal(replacements[0].id, 'created_at');
             assert.equal(replacements[0].getValue(member), '13 March 2023');
         });
+
+        it('handles dates when the locale has whitespace like "en "', function () {
+            emailRenderer = new EmailRenderer({
+                urlUtils: {
+                    urlFor: () => 'http://example.com/subdirectory/'
+                },
+                labs: {
+                    isSet: () => labsEnabled
+                },
+                settingsCache: {
+                    get: (key) => {
+                        if (key === 'timezone') {
+                            return 'UTC';
+                        }
+                        if (key === 'locale') {
+                            return 'en ';
+                        }
+                    }
+                },
+                settingsHelpers: {getMembersValidationKey,createUnsubscribeUrl},
+                t: t
+            });
+            const html = '%%{created_at}%%';
+            const replacements = emailRenderer.buildReplacementDefinitions({html, newsletterUuid: newsletter.get('uuid')});
+            assert.equal(replacements.length, 2);
+            assert.equal(replacements[0].token.toString(), '/%%\\{created_at\\}%%/g');
+            assert.equal(replacements[0].id, 'created_at');
+            assert.equal(replacements[0].getValue(member), '13 March 2023');
+        });
+
+        it('handles dates when the locale is invalid like "(en)"', function () {
+            emailRenderer = new EmailRenderer({
+                urlUtils: {
+                    urlFor: () => 'http://example.com/subdirectory/'
+                },
+                labs: {
+                    isSet: () => labsEnabled
+                },
+                settingsCache: {
+                    get: (key) => {
+                        if (key === 'timezone') {
+                            return 'UTC';
+                        }
+                        if (key === 'locale') {
+                            return '(en)';
+                        }
+                    }
+                },
+                settingsHelpers: {getMembersValidationKey,createUnsubscribeUrl},
+                t: t
+            });
+
+            const html = '%%{created_at}%%';
+            const replacements = emailRenderer.buildReplacementDefinitions({html, newsletterUuid: newsletter.get('uuid')});
+            assert.equal(replacements.length, 2);
+            assert.equal(replacements[0].token.toString(), '/%%\\{created_at\\}%%/g');
+            assert.equal(replacements[0].id, 'created_at');
+            assert.equal(replacements[0].getValue(member), '13 March 2023');
+        });
     });
     describe('isMemberTrialing', function () {
         let emailRenderer;