provide "delete own comments" as a configurable option

plone/app/discussion/browser/comments.pt

@@ -36,7 +36,8 @@
                              has_author_link python:author_home_url and not isAnon;
                              portrait_url python:view.get_commenter_portrait(reply.author_username);
 			     review_state python:wtool.getInfoFor(reply, 'review_state', 'none');
-			     canEdit python:view.can_edit(reply)"
+			     canEdit python:view.can_edit(reply);
+                             canDelete python:view.can_delete(reply)"
                  tal:attributes="class python:'comment replyTreeLevel'+str(depth)+' state-'+str(review_state);
                                  id string:${reply/getId}"
                  tal:condition="python:canReview or review_state == 'published'">
@@ -89,7 +90,7 @@
                               action=""
                               method="post"
                               class="commentactionsform"
-                              tal:condition="python:canReview"
+                              tal:condition="python:canDelete"
                               tal:attributes="action string:${reply/absolute_url}/@@moderate-delete-comment">
                             <input name="form.button.DeleteComment"
                                    class="destructive"

plone/app/discussion/browser/comments.py

@@ -318,12 +318,28 @@ class CommentsViewlet(ViewletBase):
                                                     aq_inner(self.context))
 
     def can_edit(self, reply):
-        """Returns true if current user has the 'Delete objects'
+        """Returns true if current user has the 'Edit comments'
         permission.
         """
         return getSecurityManager().checkPermission('Edit comments',
                                                     aq_inner(reply))
 
+    def can_delete(self, reply):
+        """By default requires 'Review comments'.
+        If 'delete own comments' is enabled, requires 'Edit comments'.
+        """
+        if self.is_delete_own_comment_allowed():
+            permission = 'Edit comments'
+        else:
+            permission = 'Review comments'
+        return getSecurityManager().checkPermission(permission,
+                                                    aq_inner(reply))
+
+    def is_delete_own_comment_allowed(self):
+        registry = queryUtility(IRegistry)
+        settings = registry.forInterface(IDiscussionSettings, check=False)
+        return settings.delete_own_comment_enabled
+
     def is_discussion_allowed(self):
         context = aq_inner(self.context)
         return context.restrictedTraverse('@@conversation_view').enabled()

plone/app/discussion/browser/configure.zcml

@@ -80,13 +80,15 @@
         permission="plone.app.discussion.EditComments"
         />
 
-    <!-- Delete comment view -->
+    <!-- Delete comment view
+         has conditional security dependent on controlpanel settings.
+    -->
     <browser:page
         for="plone.app.discussion.interfaces.IComment"
         name="moderate-delete-comment"
         layer="..interfaces.IDiscussionLayer"
         class=".moderation.DeleteComment"
-        permission="plone.app.discussion.ReviewComments"
+        permission="zope2.DeleteObjects"
         />
 
     <!-- Publish comment view -->

plone/app/discussion/browser/controlpanel.py

@@ -54,6 +54,8 @@ class DiscussionSettingsEditForm(controlpanel.RegistryEditForm):
             SingleCheckBoxFieldWidget
         self.fields['edit_comment_enabled'].widgetFactory = \
             SingleCheckBoxFieldWidget
+        self.fields['delete_own_comment_enabled'].widgetFactory = \
+            SingleCheckBoxFieldWidget
         self.fields['anonymous_comments'].widgetFactory = \
             SingleCheckBoxFieldWidget
         self.fields['show_commenter_image'].widgetFactory = \

plone/app/discussion/browser/moderation.py

@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
 from Acquisition import aq_inner, aq_parent
+from AccessControl import getSecurityManager
+from zope.component import queryUtility
 
 from Products.Five.browser import BrowserView
 from Products.Five.browser.pagetemplatefile import ViewPageTemplateFile
@@ -8,6 +10,8 @@ from Products.CMFCore.utils import getToolByName
 
 from Products.statusmessages.interfaces import IStatusMessage
 
+from plone.registry.interfaces import IRegistry
+from plone.app.discussion.interfaces import IDiscussionSettings
 from plone.app.discussion.interfaces import _
 from plone.app.discussion.interfaces import IComment
 
@@ -94,17 +98,37 @@ class DeleteComment(BrowserView):
         comment = aq_inner(self.context)
         conversation = aq_parent(comment)
         content_object = aq_parent(conversation)
-        del conversation[comment.id]
-        content_object.reindexObject(idxs=['total_comments'])
-        IStatusMessage(self.context.REQUEST).addStatusMessage(
-            _("Comment deleted."),
-            type="info")
+        # conditional security
+        # base ZCML condition zope2.deleteObject allows 'delete own object'
+        # modify this for 'delete_own_comment_allowed' controlpanel setting
+        if self.can_delete(comment):
+            del conversation[comment.id]
+            content_object.reindexObject()
+            IStatusMessage(self.context.REQUEST).addStatusMessage(
+                _("Comment deleted."),
+                type="info")
         came_from = self.context.REQUEST.HTTP_REFERER
         # if the referrer already has a came_from in it, don't redirect back
         if len(came_from) == 0 or 'came_from=' in came_from:
             came_from = content_object.absolute_url()
         return self.context.REQUEST.RESPONSE.redirect(came_from)
 
+    def can_delete(self, reply):
+        """By default requires 'Review comments'.
+        If 'delete own comments' is enabled, requires 'Edit comments'.
+        """
+        if self.is_delete_own_comment_allowed():
+            permission = 'Edit comments'
+        else:
+            permission = 'Review comments'
+        return getSecurityManager().checkPermission(permission,
+                                                    aq_inner(reply))
+
+    def is_delete_own_comment_allowed(self):
+        registry = queryUtility(IRegistry)
+        settings = registry.forInterface(IDiscussionSettings, check=False)
+        return settings.delete_own_comment_enabled
+
 
 class PublishComment(BrowserView):
     """Publish a comment.

plone/app/discussion/configure.zcml

@@ -54,6 +54,16 @@
         profile="plone.app.discussion:default"
     />
 
+    <genericsetup:upgradeStep
+        title="delete own comments"
+        description="reload registry config to enable new field delete_own_comment_enabled"
+        source="101"
+        destination="102"
+        handler=".upgrades.update_registry"
+        sortkey="1"
+        profile="plone.app.discussion:default"
+    />
+
 
     <!-- Monkey Patches -->
 

plone/app/discussion/interfaces.py

@@ -254,6 +254,17 @@ class IDiscussionSettings(Interface):
         default=False,
     )
 
+    delete_own_comment_enabled = schema.Bool(
+        title=_(u"label_delete_own_comment_enabled",
+                default="Allow users to delete their own comment threads"),
+        description=_(u"help_edit_comment_enabled",
+                      default=u"If selected, users may delete their own "
+                      "comments -> AND the whole reply thread below that "
+                      "comment!"),
+        required=False,
+        default=False,
+    )
+
     text_transform = schema.Choice(
         title=_(u"label_text_transform",
                 default="Comment text transform"),

plone/app/discussion/profiles/default/metadata.xml

@@ -1,5 +1,5 @@
 <metadata>
- <version>101</version>
+ <version>102</version>
  <dependencies>
   <dependency>profile-plone.app.registry:default</dependency>
  </dependencies>

plone/app/discussion/tests/functional_test_comments.txt

@@ -320,6 +320,146 @@ But Anon can see the edited comment.
     True
 
 
+Deleting existing comments | 'delete own comments' disabled
+-----------------------------------------------------------
+
+Anonymous cannot delete comments
+
+    >>> unprivileged_browser.open(urldoc1)
+    >>> 'form.button.Delete' in unprivileged_browser.contents
+    False
+
+A member cannot delete his own comments, unless this is explicitly enabled (see later)
+
+    >>> browser_member.open(urldoc1)
+    >>> 'form.button.Delete' in browser_member.contents
+    False
+
+Admin can delete comments
+
+    >>> browser.open(urldoc1)
+    >>> 'form.button.Delete' in browser.contents
+    True
+
+Extract the delete comment url from the first "delete comment" button
+
+    >>> browser.open(urldoc1)
+    >>> form = browser.getForm(name='delete', index=0)
+    >>> delete_url = form.action
+    >>> '@@moderate-delete-comment' in delete_url
+    True
+    >>> comment_id = delete_url.split('/')[-2]
+
+Anonymous cannot delete a comment by hitting the delete url directly.
+
+    >>> unprivileged_browser.open(delete_url)
+
+The comment is still there
+
+    >>> unprivileged_browser.open(urldoc1)
+    >>> comment_id in unprivileged_browser.contents
+    True
+
+
+A Member cannot delete even his own comment by hitting the delete url directly.
+
+Extract the member comment id from the admin browser
+
+    >>> form = browser.getForm(name='delete', index=2)
+    >>> delete_url = form.action
+    >>> '@@moderate-delete-comment' in delete_url
+    True
+    >>> comment_id = delete_url.split('/')[-2]
+
+Now try to hit that url as the member owning that comment.
+Work around some possible testbrowser breakage and check the result later.
+
+    >>> try:
+    ...   browser_member.open(delete_url)
+    ... except:
+    ...   pass
+
+The comment is still there
+
+    >>> browser_member.open(urldoc1)
+    >>> comment_id in browser_member.contents
+    True
+    >>> 'Comment from Jim' in browser_member.contents
+    True
+
+Admin, who hase 'review comments' permission, can delete comments
+
+    >>> browser.open(urldoc1)
+    >>> form = browser.getForm(name='delete', index=0)
+    >>> '@@moderate-delete-comment' in form.action
+    True
+
+    >>> comment_id = form.action.split('/')[-2]
+
+Submitting the form runs into a testbrowser notFoundException.
+We'll just catch that and check the result later.
+
+    >>> try:
+    ...   form.submit()    
+    ... except:
+    ...   pass
+
+Returning to the document we find the deleted comment is indeed gone
+
+    >>> browser.open(urldoc1)
+    >>> comment_id in browser.contents
+    False
+
+
+Deleting existing comments | 'delete own comments' ENABLED
+----------------------------------------------------------
+
+Enable deletion of own comments
+
+    >>> from zope.component import queryUtility
+    >>> from plone.registry.interfaces import IRegistry
+    >>> from plone.app.discussion.interfaces import IDiscussionSettings
+    >>> registry = queryUtility(IRegistry)
+    >>> settings = registry.forInterface(IDiscussionSettings)
+    >>> settings.delete_own_comment_enabled = True
+
+    >>> import transaction
+    >>> transaction.commit()
+
+Anonymous still cannot delete comments
+
+    >>> unprivileged_browser.open(urldoc1)
+    >>> 'form.button.Delete' in unprivileged_browser.contents
+    False
+
+A member can now delete his own comments
+
+    >>> browser_member.open(urldoc1)
+    >>> 'form.button.Delete' in browser_member.contents
+    True
+
+    >>> form = browser_member.getForm(name='delete', index=0)
+    >>> '@@moderate-delete-comment' in form.action
+    True
+
+    >>> comment_id = form.action.split('/')[-2]
+
+Submitting the form runs into a testbrowser notFoundException.
+We'll just catch that and check the result later.
+
+    >>> try:
+    ...   form.submit()    
+    ... except:
+    ...   pass
+
+Returning to the document we find the deleted comment is indeed gone
+
+    >>> browser_member.open(urldoc1)
+    >>> comment_id in browser_member.contents
+    False
+    >>> 'Comment from Jim' in browser_member.contents
+    False
+
 
 Post a comment with comment review workflow enabled
 ---------------------------------------------------