Keep in sync redundant fields found in the new Social Media configlet

Changes on facebook_app_id, facebook_username, or twitter_username fields will be reflected in both configlets.

CHANGES.rst

@@ -6,7 +6,9 @@ There's a frood who really knows where his towel is.
 2.10 (unreleased)
 ^^^^^^^^^^^^^^^^^
 
-- Nothing changed yet.
+- In Plone 5, keep in sync some redundant fields found in the new Social Media configlet.
+  Changes on ``facebook_app_id``, ``facebook_username``, or ``twitter_username`` fields will be reflected in both configlets (fixes `#100`_).
+  [hvelarde]
 
 
 2.9 (2017-03-09)
@@ -277,3 +279,4 @@ Previous entries can be found in the HISTORY.rst file.
 .. _`#65`: https://github.com/collective/sc.social.like/issues/65
 .. _`#83`: https://github.com/collective/sc.social.like/issues/83
 .. _`#91`: https://github.com/collective/sc.social.like/issues/91
+.. _`#100`: https://github.com/collective/sc.social.like/issues/100

sc/social/like/configure.zcml

@@ -22,4 +22,9 @@
        name="sc.social.likes.plugins"
        />
 
+  <subscriber
+      for="plone.registry.interfaces.IRecordModifiedEvent"
+      handler=".subscribers.social_media_record_synchronizer"
+      />
+
 </configure>

sc/social/like/subscribers.py

@@ -0,0 +1,74 @@
+# -*- coding: utf-8 -*-
+"""Package event subscribers.
+
+Plone 5 includes a new social media configlet that duplicates some
+records already included in this package. To deal with that we use
+an event subscriber declared in this module to synchronize the values
+of the redundant records on every change.
+"""
+from plone import api
+from plone.registry.interfaces import IRegistry
+from sc.social.like.config import IS_PLONE_5
+from sc.social.like.config import PROJECTNAME
+from sc.social.like.interfaces import ISocialLikeSettings
+from sc.social.like.logger import logger
+from zope.component import getUtility
+from zope.schema.interfaces import WrongType
+
+
+# redundant fields so far
+FIELDS = ('facebook_app_id', 'facebook_username', 'twitter_username')
+
+# used to avoid RuntimeError due to infinite recursion
+_FLAG = False
+
+
+def social_media_record_synchronizer(event):
+    """Synchronize Plone 5 social media records if needed."""
+    # subscribers are registered even if packages are not installed
+    qi = api.portal.get_tool('portal_quickinstaller')
+    if not qi.isProductInstalled(PROJECTNAME):
+        return
+
+    if not IS_PLONE_5:
+        return
+
+    # check if we've been here before as part of same event processing
+    global _FLAG
+    if _FLAG:
+        return
+
+    logger.info(u'Processing: ' + repr(event.record))
+    field = event.record.fieldName
+    if field not in FIELDS:
+        logger.info(u'No need to synchronize')
+        return
+
+    # find out which record we need to synchronize
+    from Products.CMFPlone.interfaces.controlpanel import ISocialMediaSchema
+    interface = event.record.interfaceName
+    if interface == ISocialLikeSettings.__identifier__:
+        # sc.social.like record modified; synchronize Plone record
+        record = 'plone.' + field
+    elif interface == ISocialMediaSchema.__identifier__:
+        # Plone record modified; synchronize sc.social.like record
+        record = ISocialLikeSettings.__identifier__ + '.' + field
+    else:
+        # unsupported interface name
+        logger.info(u'No need to synchronize')
+        return
+
+    registry = getUtility(IRegistry)
+    # we're going to modify a record and this will fire the same event
+    # we need to avoid RuntimeError due to infinite recursion
+    _FLAG = True
+    try:
+        registry[record] = str(event.record.value)
+    except WrongType:
+        # Plone 5 declares records as TextLine
+        registry[record] = unicode(event.record.value)
+    _FLAG = False
+
+    msg = '{0} was synchronized; new value is "{1}"'
+    logger.info(
+        msg.format(repr(registry.records[record]), event.record.value))