From aff8a3709c380871bf61ec6640aa12bb61be30d1 Mon Sep 17 00:00:00 2001
From: Maurits van Rees <maurits@vanrees.org>
Date: Wed, 15 Dec 2010 23:41:57 +0000
Subject: [PATCH] Avoid sending multiple notification emails to the same person
 when he has commented multiple times.

svn path=/plone.app.discussion/trunk/; revision=46365
---
 CHANGES.txt                                   |  4 +
 plone/app/discussion/comment.py               | 80 +++++++++++--------
 .../discussion/tests/test_notifications.py    | 34 ++++++++
 3 files changed, 83 insertions(+), 35 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 9768b9d..1dd08b7 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -4,6 +4,10 @@ Changelog
 1.0RC1 (unreleased)
 -------------------
 
+- Avoid sending multiple notification emails to the same person when
+  he has commented multiple times.
+  [maurits]
+
 - Disable discussion by default.
   [timo]
   
diff --git a/plone/app/discussion/comment.py b/plone/app/discussion/comment.py
index ba398ba..1a73ca4 100644
--- a/plone/app/discussion/comment.py
+++ b/plone/app/discussion/comment.py
@@ -219,42 +219,52 @@ def notify_user(obj, event):
     # conversation and enabled user_notification.
     conversation = aq_parent(obj)
     content_object = aq_parent(conversation)
-    
+
+    # Avoid sending multiple notification emails to the same person
+    # when he has commented multiple times.
+    emails = set()
     for comment in conversation.getComments():
-        if obj != comment and \
-        comment.user_notification and comment.author_email:
-            subject = translate(_(u"A comment has been posted."),
-                context=obj.REQUEST)
-            message = translate(Message(MAIL_NOTIFICATION_MESSAGE,
-                mapping={'title': content_object.title,
-                         'link': content_object.absolute_url()}),
-                context=obj.REQUEST)
-        
-            # Send email
-            if PLONE_4:
-                try:
-                    mail_host.send(message, 
-                                   comment.author_email, 
-                                   sender, 
-                                   subject, 
-                                   charset='utf-8')
-                except SMTPException:
-                    logger.error('SMTP exception while trying to send an ' +
-                                 'email from %s to %s',
-                                 sender,
-                                 comment.author_email)
-            else: # pragma: no cover
-                try:
-                    mail_host.secureSend(message, 
-                                         comment.author_email,
-                                         sender,
-                                         subject=subject,
-                                         charset='utf-8')
-                except SMTPException:
-                    logger.error('SMTP exception while trying to send an ' +
-                                 'email from %s to %s',
-                                 sender,
-                                 comment.author_email)
+        if (obj != comment and
+            comment.user_notification and comment.author_email):
+            emails.add(comment.author_email)
+
+    if not emails:
+        return
+
+    subject = translate(_(u"A comment has been posted."),
+                        context=obj.REQUEST)
+    message = translate(Message(
+            MAIL_NOTIFICATION_MESSAGE,
+            mapping={'title': content_object.title,
+                     'link': content_object.absolute_url()}),
+                        context=obj.REQUEST)
+    for email in emails:
+        # Send email
+        if PLONE_4:
+            try:
+                mail_host.send(message,
+                               email,
+                               sender,
+                               subject,
+                               charset='utf-8')
+            except SMTPException:
+                logger.error('SMTP exception while trying to send an ' +
+                             'email from %s to %s',
+                             sender,
+                             email)
+        else:  # pragma: no cover
+            try:
+                mail_host.secureSend(message,
+                                     email,
+                                     sender,
+                                     subject=subject,
+                                     charset='utf-8')
+            except SMTPException:
+                logger.error('SMTP exception while trying to send an ' +
+                             'email from %s to %s',
+                             sender,
+                             email)
+
 
 def notify_moderator(obj, event):
     """Tell the moderator when a comment needs attention.
diff --git a/plone/app/discussion/tests/test_notifications.py b/plone/app/discussion/tests/test_notifications.py
index baa00e3..312ad13 100644
--- a/plone/app/discussion/tests/test_notifications.py
+++ b/plone/app/discussion/tests/test_notifications.py
@@ -129,6 +129,40 @@ class TestUserNotificationUnit(PloneTestCase):
         
         self.assertEquals(len(self.mailhost.messages), 0)
 
+    def test_notify_only_once(self):
+        # When a user has added two comments in a conversation and has
+        # both times requested email notification, do not send him two
+        # emails when another comment has been added.
+
+        # Comment 1
+        comment = createObject('plone.Comment')
+        comment.text = 'Comment text'
+        comment.user_notification = True
+        comment.author_email = "john@plone.test"
+        self.conversation.addComment(comment)
+
+        # Comment 2
+        comment = createObject('plone.Comment')
+        comment.text = 'Comment text'
+        comment.user_notification = True
+        comment.author_email = "john@plone.test"
+        self.conversation.addComment(comment)
+        # Note that we might want to get rid of this message, as the
+        # new comment is added by the same user.
+        self.assertEquals(len(self.mailhost.messages), 1)
+        self.mailhost.reset()
+        self.assertEquals(len(self.mailhost.messages), 0)
+
+        # Comment 3
+        comment = createObject('plone.Comment')
+        comment.text = 'Comment text'
+        self.conversation.addComment(comment)
+        self.assertEquals(len(self.mailhost.messages), 1)
+        self.failUnless(self.mailhost.messages[0])
+        msg = str(self.mailhost.messages[0])
+        self.failUnless('To: john@plone.test' in msg)
+        self.failUnless('From: portal@plone.test' in msg)
+
 
 class TestModeratorNotificationUnit(PloneTestCase):