feat: add endpoint to send welcome email

apps/meteor/app/api/server/v1/users.ts

@@ -644,6 +644,26 @@ API.v1.addRoute(
 	},
 );
 
+API.v1.addRoute(
+	'users.sendWelcomeEmail',
+	{
+		authRequired: true,
+	},
+	{
+		async post() {
+			const { email } = this.bodyParams;
+			if (!email) {
+				return API.v1.failure("The 'email' param is required");
+			}
+
+			if (await Meteor.callAsync('sendWelcomeEmail', email)) {
+				return API.v1.success();
+			}
+			return API.v1.failure();
+		},
+	},
+);
+
 API.v1.addRoute(
 	'users.register',
 	{

apps/meteor/server/main.ts

@@ -63,6 +63,7 @@ import './methods/saveUserPreferences';
 import './methods/saveUserProfile';
 import './methods/sendConfirmationEmail';
 import './methods/sendForgotPasswordEmail';
+import './methods/sendWelcomeEmail';
 import './methods/setAvatarFromService';
 import './methods/setUserActiveStatus';
 import './methods/setUserPassword';

apps/meteor/server/methods/sendWelcomeEmail.ts

@@ -0,0 +1,49 @@
+import { Users } from '@rocket.chat/models';
+import type { ServerMethods } from '@rocket.chat/ui-contexts';
+import { check } from 'meteor/check';
+import { Meteor } from 'meteor/meteor';
+
+import * as Mailer from '../../app/mailer/server/api';
+import { settings } from '../../app/settings/server';
+
+declare module '@rocket.chat/ui-contexts' {
+	// eslint-disable-next-line @typescript-eslint/naming-convention
+	interface ServerMethods {
+		sendWelcomeEmail(to: string): boolean | undefined;
+	}
+}
+
+Meteor.methods<ServerMethods>({
+	async sendWelcomeEmail(to) {
+		check(to, String);
+
+		const email = to.trim();
+
+		const user = await Users.findOneByEmailAddress(email, { projection: { _id: 1 } });
+
+		if (!user) {
+			return false;
+		}
+
+		try {
+			let html = '';
+			Mailer.getTemplate('Accounts_UserAddedEmail_Email', (template) => {
+				html = template;
+			});
+
+			await Mailer.send({
+				to: email,
+				from: settings.get('From_Email'),
+				subject: settings.get('Accounts_UserAddedEmail_Subject'),
+				html,
+			});
+
+			return true;
+		} catch (error: any) {
+			throw new Meteor.Error('error-email-send-failed', `Error trying to send email: ${error.message}`, {
+				method: 'sendWelcomeEmail',
+				message: error.message,
+			});
+		}
+	},
+});

packages/rest-typings/src/v1/users.ts

@@ -157,6 +157,10 @@ export type UsersEndpoints = {
 		}>;
 	};
 
+	'/v1/users.sendWelcomeEmail': {
+		POST: (params: { email: string }) => void;
+	};
+
 	'/v1/users.setAvatar': {
 		POST: (params: UsersSetAvatar) => void;
 	};