[Seaside] Executing form callbacks within a block

[jtuchel at objektfabrik.de]

Esteban,

not sure if I understand correctly, but I would like to point you to an 
idea I got from a Form validation framework called mold 
(https://github.com/grype/Seaside-Mold 
<https://github.com/grype/Seaside-Mold>). Your hidden input idea is 
going to carry you quite far, but you can even make it a bit "safer" by 
creating a special callback that has a higher priority than the other 
action  callbacks.

Just subclass WAActionCallback and implement #priority to return a value 
lower than 5 to make sure it is executed before the action callbacks 
(but after the value callbacks).

This will be a bit safer than just relying on the order of the action 
callbacks in your form (which might be enough already).

HTH

Joachim





Am 20.05.21 um 16:10 schrieb Esteban Maringolo:
> Well..
>
> I'm not writing the values directly to the database, but I'm using
> GLORP in between.
> Glorp detects changes and at the end of a "unit of work" (kinda
> transaction) it creates the corresponding statements to
> write/update/delete rows in the database. But in order to do that it
> has to know the object "state" before starting doing mutations on it.
>
> So what I finally did was to have a hidden input as the first callback.
>
> A super simplified version, without validations and whatnot is like this:
>
> html form: [
>    html hiddenInput callback: [self db beginUnitOrWork. self db
> register: self model].
>    html textInput on: #name of: self model.
>    html submitButton callback: [self db commitUnitOfWork]
> ]
>
> Regards!
>
> Esteban A. Maringolo
>
> On Wed, May 19, 2021 at 10:59 PM Jupiter Jones <jupiter.jones at mail.com> wrote:
>> To be clearer… :)
>>
>> No callback on the submit button.
>>
>> html form callback: [
>>          self beginTransaction.
>>          “Update database from #name and #age fields”
>>          self commitTransaction
>> ]
>>
>>> On 20 May 2021, at 11:55 am, Jupiter Jones <jupiter.jones at mail.com> wrote:
>>>
>>> It’s been a while since I’ve done this, but if you have a callback on the form itself, which handles validation and if valid, starts a transaction, moves the data from the temporary variables used by the web form to the database, then commits.
>>>
>>> I’m guessing from the question that you may have bound your inputs directly to database objects that will revert their value when you beginTransaction?
>>>
>>>> On 20 May 2021, at 11:18 am, Esteban Maringolo <emaringolo at gmail.com> wrote:
>>>>
>>>> Hi all,
>>>>
>>>> I have a situation where I want to execute _ALL_ the callbacks of the
>>>> inputs in the form within a particular block (basically, a DB
>>>> transaction).
>>>>
>>>> html form: [
>>>> html textInput on: #name of: self.
>>>> html textInput on: #age of: self.
>>>> html submitButton
>>>> ]
>>>>
>>>> I want to execute the three callbacks within something else, or at
>>>> least have the option to execute something before the first callback
>>>> executes and ensure something gets executed after the last one is
>>>> executed.
>>>>
>>>> I know it involves fiddling somehow with
>>>> WACallbackProcessingActionContinuation, but it's not fully clear if I
>>>> could do this.
>>>>
>>>> The hacky alternative would be to have a hidden field that does start
>>>> the tx and the submit / cancel commits or cancels it.
>>>>
>>>> html form: [
>>>> html hiddenInput callback: [self beginTransaction].
>>>> html textInput on: #name of: self.
>>>> html textInput on: #age of: self.
>>>> html submitButton
>>>>    callback: [self commitTransaction];
>>>>    value: 'Submit'.
>>>> ]
>>>>
>>>> But in this case I'd have to keep the tx "outside" of the form, and
>>>> I'd like to wrap everything in a single block.
>>>>
>>>> Is there a way to do this with Seaside?
>>>>
>>>> Thanks!
>>>>
>>>> Esteban A. Maringolo
>>>> _______________________________________________
>>>> seaside mailing list
>>>> seaside at lists.squeakfoundation.org
>>>> http://lists.squeakfoundation.org/cgi-bin/mailman/listinfo/seaside
> _______________________________________________
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> seaside at lists.squeakfoundation.org
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