changed emailer.send so that it processes a callback, if provided. Also added new option to receive emails every time a topic you subscribe to is posted to.

public/language/en_GB/email.json

@@ -23,6 +23,9 @@
 	"notif.chat.cta": "Click here to continue the conversation",
 	"notif.chat.unsub.info": "This chat notification was sent to you due to your subscription settings.",
 
+	"notif.post.cta": "Click here to read the full topic",
+	"notif.post.unsub.info": "This post notification was sent to you due to your subscription settings.",
+
 	"test.text1": "This is a test email to verify that the emailer is set up correctly for your NodeBB.",
 
 	"unsub.cta": "Click here to alter those settings",

public/language/en_GB/user.json

@@ -64,6 +64,7 @@
 	"digest_weekly": "Weekly",
 	"digest_monthly": "Monthly",
 	"send_chat_notifications": "Send an email if a new chat message arrives and I am not online",
+	"send_post_notifications": "Send an email when replies are made to topics I am subscribed to",
 
 	"has_no_follower": "This user doesn't have any followers :(",
 	"follows_no_one": "This user isn't following anyone :(",

src/emailer.js

@@ -19,10 +19,10 @@ var	fs = require('fs'),
 		return Emailer;
 	};
 
-	Emailer.send = function(template, uid, params) {
+	Emailer.send = function(template, uid, params, callback) {
 		if (!app) {
 			winston.warn('[emailer] App not ready!');
-			return;
+			return callback();
 		}
 
 		async.parallel({
@@ -36,7 +36,8 @@ var	fs = require('fs'),
 			settings: async.apply(User.getSettings, uid)
 		}, function(err, results) {
 			if (err) {
-				return winston.error('[emailer] Error sending digest : ' + err.stack);
+				winston.error('[emailer] Error sending digest : ' + err.stack);
+				return callback(err);
 			}
 			async.map([results.html, results.plaintext, params.subject], function(raw, next) {
 				translator.translate(raw, results.settings.language || meta.config.defaultLang || 'en_GB', function(translated) {
@@ -44,9 +45,11 @@ var	fs = require('fs'),
 				});
 			}, function(err, translated) {
 				if (err) {
-					return winston.error(err.message);
+					winston.error(err.message);
+					return callback(err);
 				} else if (!results.email) {
-					return winston.warn('uid : ' + uid + ' has no email, not sending.');
+					winston.warn('uid : ' + uid + ' has no email, not sending.');
+					return callback();
 				}
 
 				if (Plugins.hasListeners('action:email.send')) {
@@ -57,10 +60,12 @@ var	fs = require('fs'),
 						html: translated[0],
 						plaintext: translated[1],
 						template: template,
-						uid: uid
+						uid: uid,
+						pid: params.pid
 					});
 				} else {
 					winston.warn('[emailer] No active email plugin found!');
+					callback();
 				}
 			});
 		});

src/topics/follow.js

@@ -9,7 +9,9 @@ var async = require('async'),
 	user = require('../user'),
 	posts = require('../posts'),
 	postTools = require('../postTools'),
-	notifications = require('../notifications');
+	notifications = require('../notifications'),
+	meta = require('../meta'),
+	emailer = require('../emailer');
 
 module.exports = function(Topics) {
 
@@ -125,6 +127,24 @@ module.exports = function(Topics) {
 					notifications.push(notification, followers);
 				}
 			});
+
+			async.eachLimit(followers, 3, function(toUid, next) {
+				async.parallel({
+					userData: async.apply(user.getUserFields, toUid, ['username']),
+					userSettings: async.apply(user.getSettings, toUid)
+				}, function(err, data) {
+					emailer.send('notif_post', toUid, {
+						pid: postData.pid,
+						subject: '[' + (meta.config.title || 'NodeBB') + '] ' + title,
+						intro: '[[notifications:user_posted_to, ' + postData.user.username + ', ' + title + ']]',
+						postBody: postData.content,
+						site_title: meta.config.title || 'NodeBB',
+						username: data.userData.username,
+						url: nconf.get('url') + '/topics/' + postData.topic.tid,
+						base_url: nconf.get('url')
+					}, next);
+				});
+			});
 		});
 	};
 };

src/views/emails/notif_post.tpl

@@ -0,0 +1,16 @@
+<p>[[email:greeting_with_name, {username}]],</p>
+
+<p>{intro}:</p>
+<blockquote>{postBody}</blockquote>
+
+<a href="{url}">[[email:notif.post.cta]]</a>
+
+<p>
+	[[email:closing]]<br />
+	<strong>{site_title}</strong>
+</p>
+
+<hr />
+<p>
+	[[email:notif.post.unsub.info]] <a href="{base_url}/user/{username}/settings">[[email:unsub.cta]]</a>.
+</p>

src/views/emails/notif_post_plaintext.tpl

@@ -0,0 +1,14 @@
+[[email:greeting_with_name, {username}]],
+
+{intro}:
+
+{postBody}
+
+[[email:notif.post.cta]]: {url}
+
+[[email:closing]]
+{site_title}
+
+===
+
+[[email:notif.post.unsub.info]] <a href="{base_url}/user/{username}/settings">[[email:unsub.cta]]</a>.