On Thursday, April 11, 2019 at 7:52:18 AM UTC-4, João Matos wrote:
>
> Thanks for the explanations.
>
> You don't understand. I don't care if the changes made at the same time
> the deleted checkbox is selected, are saved when submitting. That is not
> the problem.
> It is a question of consistency.
>
> Either web2py should call on_validation when the delete checkbox is
> selected or not. What happens now is that in some scenarios it is called
> but not in others.
> My opinion is that it should always be called, but above all, it should be
> consistent.
>
The "onvalidation" function is supposed to be called "upon validation"
(hence the name), meaning after a successful validation of the submitted
field values. It is not intended to be run in order to make checks before
or after deletion of a record. In other words, onvalidation runs when
particular conditions are met, and it does so *consistently*. It just so
happens that you want to run it under different conditions, which is not
its intended purpose. Even if it did run when you want, you would still
need a way to distinguish a regular update request from a delete request,
and you can do that just as easily outside of the onvalidation function
(see below).
I think there are three types of cases to handle regarding deletes:
First, you might want to simply allow/disallow a delete, and that case is
handled by the "deletable" argument.
Second, you might want to run some code *after* a successful delete. The
grid has an "ondelete" argument to handle that in case the "Delete" button
is clicked, but nothing for the case when a delete happens via an edit
form. However, this can be handled in all cases via the
db.mytable._after_delete callback. In any case, the onvalidation function
would not be the best place for this logic as it (a) runs *before *the
delete happens, and (b) would still require some logic to determine that a
delete was requested. It might be nice if SQLFORM had a separate "ondelete"
argument of its own.
Finally, you might want to allow the user to request a delete and then kick
off a separate workflow, such as requiring a special password. However,
that is really a special case that is application specific, and it is not
even well accommodated by the current UI (i.e., it would be a better user
experience to request the special password up front rather than making it a
two step process). If you need something like that, you should really be
implementing custom logic. And again, the onvalidation function is not the
best place for such logic, as it would still require detection of the
delete request.
As an aside, note that the "onvalidation" argument can actually be a
dictionary with separate "onsuccess", "onfailure", and "onchange"
callbacks. The grid also has "onupdate" (run after successful update) and
"onfailure" (run after failed update) arguments, as well as the "ondelete"
argument. Some combination of these callbacks could be used to run some
code whenever a delete is requested, though it is probably simpler to just
do a check like the following before calling grid():
if SQLFORM.FIELDNAME_REQUEST_DELETE in request.post_vars or 'delete' in
request.args:
[code to handle delete workflow]
Anthony
--
Resources:
- http://web2py.com
- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
---
You received this message because you are subscribed to the Google Groups
"web2py-users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
