[Seaside] Executing form callbacks within a block
Johan Brichau
johan at inceptive.be
Thu May 20 19:07:29 UTC 2021
Hi Esteban,
Seaside’s defined callback priorities guarantee that the submit button callback is executed after the value callbacks on the input form’s fields.
Although you can fiddle with creating additional WAValueCallback subclasses, I would not recommend it.
Instead, I would collect the values in a ‘value collector’ object, like what Karsten proposes. Roughly:
collector := MyValueCollector new.
html form:[
html textInput callback: [ :e | collector setA: e];
html textInput callback: [ :e | collector setB: e];
html submitButton callback: [ collector save ] ]
When the first value is added to the collector, you execute the code that needs to be executed first (i.e. ’start transaction’). The collector knows because it gathers all the values.
The submit button callback then executes the final action (’save’).
Is that not the easiest solution to what you want to achieve?
cheers
Johan
> On 20 May 2021, at 17:29, Esteban Maringolo <emaringolo at gmail.com> wrote:
>
> Hi Joachim,
>
> Thanks for pointing that out, I forgot about Mold. It's not exactly
> what I needed, but having a special kind of callback is something I
> could certainly use. I did that for specific purposes but never for
> changing the processing priority.
>
> Thanks again!
>
>
> Esteban A. Maringolo
>
> On Thu, May 20, 2021 at 11:30 AM jtuchel at objektfabrik.de
> <jtuchel at objektfabrik.de> wrote:
>>
>> 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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>>
>> --
>> -----------------------------------------------------------------------
>> Objektfabrik Joachim Tuchel mailto:jtuchel at objektfabrik.de
>> Fliederweg 1 http://www.objektfabrik.de
>> D-71640 Ludwigsburg http://joachimtuchel.wordpress.com
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>>
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