[Checkins] SVN: plone.z3cform/trunk/ Allow ICrudForm.add to raise ValidationError, which allows for

[Daniel Nouri]

Log message for revision 88809:
  Allow ICrudForm.add to raise ValidationError, which allows for
  displaying a user-friendly error message.
  

Changed:
  U   plone.z3cform/trunk/docs/HISTORY.txt
  U   plone.z3cform/trunk/plone/z3cform/crud/README.txt
  U   plone.z3cform/trunk/plone/z3cform/crud/crud.py

-=-
Modified: plone.z3cform/trunk/docs/HISTORY.txt
===================================================================
--- plone.z3cform/trunk/docs/HISTORY.txt	2008-07-25 08:12:06 UTC (rev 88808)
+++ plone.z3cform/trunk/docs/HISTORY.txt	2008-07-25 08:42:57 UTC (rev 88809)
@@ -4,6 +4,9 @@
 0.4 - Unreleased
 ----------------
 
+* Allow ICrudForm.add to raise ValidationError, which allows for
+  displaying a user-friendly error message.
+
 * Make the default layout template CMFDefault- compatible.
 
 0.3 - 2008-07-24

Modified: plone.z3cform/trunk/plone/z3cform/crud/README.txt
===================================================================
--- plone.z3cform/trunk/plone/z3cform/crud/README.txt	2008-07-25 08:12:06 UTC (rev 88808)
+++ plone.z3cform/trunk/plone/z3cform/crud/README.txt	2008-07-25 08:42:57 UTC (rev 88809)
@@ -213,6 +213,40 @@
   >>> log
   []
 
+What if we try to add "Daniel" twice?  Our current implementation of
+the add form will simply overwrite the data:
+
+  >>> save_daniel = storage['Daniel']
+  >>> html = MyForm(None, request)()
+  >>> "Item added successfully" in html
+  True
+  >>> save_daniel is storage['Daniel']
+  False
+  >>> log.pop().object is storage['Daniel']
+  True
+
+Let's implement a class that prevents this:
+
+  >>> class MyCarefulForm(MyForm):
+  ...     def add(self, data):
+  ...         name = data['name']
+  ...         if name not in storage:
+  ...             return super(MyCarefulForm, self).add(data)
+  ...         else:
+  ...             raise schema.ValidationError(
+  ...                 u"There's already an item with the name '%s'" % name)
+
+  >>> save_daniel = storage['Daniel']
+  >>> html = MyCarefulForm(None, request)()
+  >>> "Item added successfully" in html
+  False
+  >>> "There's already an item with the name 'Daniel'" in html
+  True
+  >>> save_daniel is storage['Daniel']
+  True
+  >>> len(log) == 0
+  True
+
 Render some of the fields in view mode
 --------------------------------------
 

Modified: plone.z3cform/trunk/plone/z3cform/crud/crud.py
===================================================================
--- plone.z3cform/trunk/plone/z3cform/crud/crud.py	2008-07-25 08:12:06 UTC (rev 88808)
+++ plone.z3cform/trunk/plone/z3cform/crud/crud.py	2008-07-25 08:42:57 UTC (rev 88809)
@@ -43,6 +43,9 @@
 
         The `data` mapping corresponds to the schema returned by
         `add_schema`.
+
+        May raise zope.schema.ValidationError to indicate that there's
+        a problem with the add form data.
         """
 
     def remove((id, item)):
@@ -281,9 +284,13 @@
         if errors:
             self.status = form.AddForm.formErrorsMessage
             return
-        item = self.context.add(data)
-        zope.event.notify(zope.lifecycleevent.ObjectCreatedEvent(item))
-        self.status = _(u"Item added successfully.")
+        try:
+            item = self.context.add(data)
+        except zope.schema.ValidationError, e:
+            self.status = e
+        else:
+            zope.event.notify(zope.lifecycleevent.ObjectCreatedEvent(item))
+            self.status = _(u"Item added successfully.")
 
 class NullForm(object):
     def __init__(self, context, request):