37 messages in net.sourceforge.lists.plone-developersRe: CMFFormController should abort th...
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Dorneles TreméaNov 9, 2007 3:17 pm 
Philipp von WeitershausenNov 10, 2007 7:07 am 
Dorneles TreméaNov 10, 2007 7:58 am 
Wichert AkkermanNov 10, 2007 12:22 pm 
Martin AspeliNov 10, 2007 2:12 pm 
Wichert AkkermanNov 10, 2007 4:20 pm 
Philipp von WeitershausenNov 11, 2007 1:32 am 
Dorneles TreméaNov 11, 2007 5:19 pm 
Alan RunyanNov 11, 2007 5:20 pm 
Martin AspeliNov 11, 2007 5:44 pm 
Martin AspeliNov 11, 2007 5:51 pm 
Wichert AkkermanNov 12, 2007 4:37 am 
Sidnei da SilvaNov 12, 2007 4:43 am 
Daniel KraftNov 12, 2007 5:40 am 
Martin AspeliNov 12, 2007 5:52 am 
Dorneles TreméaNov 12, 2007 9:35 am 
Wichert AkkermanNov 12, 2007 9:56 am 
Martin AspeliNov 12, 2007 9:59 am 
Martin AspeliNov 12, 2007 10:00 am 
Dorneles TreméaNov 12, 2007 10:56 am 
Martin AspeliNov 12, 2007 11:14 am 
Martin AspeliNov 12, 2007 11:21 am 
Wichert AkkermanNov 12, 2007 11:36 am 
Martin AspeliNov 12, 2007 11:41 am 
Sidnei da SilvaNov 12, 2007 11:47 am 
Martin AspeliNov 12, 2007 12:04 pm 
Dorneles TreméaNov 12, 2007 12:28 pm 
Dorneles TreméaNov 12, 2007 12:34 pm 
Dorneles TreméaNov 12, 2007 1:29 pm 
Wichert AkkermanNov 12, 2007 1:32 pm 
Martin AspeliNov 12, 2007 1:41 pm 
Dorneles TreméaNov 12, 2007 1:44 pm 
Martin AspeliNov 12, 2007 1:46 pm 
Wichert AkkermanNov 12, 2007 1:46 pm 
Martin AspeliNov 12, 2007 1:47 pm 
Dorneles TreméaNov 12, 2007 5:11 pm 
Daniel NouriNov 13, 2007 4:14 am 
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Subject:Re: CMFFormController should abort the current transaction when the validation failsActions...
From:Martin Aspeli (opti@public.gmane.org)
Date:Nov 12, 2007 11:41:16 am
List:net.sourceforge.lists.plone-developers

Martin Aspeli wrote:

Follow the path with me:

- You press the 'Save' button in the Archetypes form edit screen

Check.

- That form edit screen is a ControllerPageTemplate (base_edit.cpt) with validate_base.vpy as the unique validator

Check.

- validate_base.vpy calls BaseObject.validate() to check for errors

Check.

- BaseObject.validate() calls BasicSchema.validate() which in turn calls widget.process_form() for all fields

Check. Except process_form should never write anything persistent, right. It it does, then this process is broken - you're writing when the form may be invalid!

Yes, looking at the contract for Widget.process_form, I would argue (under-documented though it is) that it's about turning form request variables into a return value that's suitable for the field. I think it's incorrect to assume that you can perform database writes there.

- We have a ReferenceField which uses a special reference widget, UploadReferenceWidget, which was designed to be a simple replacement for the default ReferenceWidget

Ok.

- That widget receives a FileUpload object via REQUEST, proceeds with a 'File' creation and only returns its UID as the widget value

This is nuts.

You're creating objects during validation. This needs to happen somewhere *after* the validation has succeeded (e.g. in an event handler such as IObjectSaved or whatever it's called in AT). That's what validation means - you're deciding if the request is valid before proceeding.

In this case, one solution may be to have a new field that implements set() to do the DB write. set() will not be called until after validation, which is what you want. This is much more in line with how other fields and widgets work.

- Now that there's already a File in ZODB, the validation of another field fails, let's say 'title' was required but nothing was passed

Right.

- At this point the validation failed and you're back to the edit form screen with no chance to abort the transaction

Right.

Martin

-- Author of `Professional Plone Development`, a book for developers who want to work with Plone. See http://martinaspeli.net/plone-book