[html-formfu] Validate DBIx::Class unique constraints

[Tim Rayner]

On 6 December 2010 10:58, Carl Franks <fireartist at gmail.com> wrote:
> On 6 December 2010 10:47, Erez Schatz <moonbuzz at gmail.com> wrote:
>> On 12/03/2010 01:35 PM, Carl Franks wrote:
>>
>>> There's also a HTML::FormFu::Constraint::DBIC::Unique
>>
>> Thanks, its a good solution, however...
>>
>>> I'm not sure what you mean by "this doesn't work if the user enters
>>> his own information", can you give an example?
>>
>> When a user profile page loads, it is populated with current
>> information. If a user clicks on "submit" it then submit all information
>> that is in the form. Any "Unique" test will fail, seeing as the
>> information is already in the DB - under the user's name!
>>
>> Is there a way to tell HTML::FF "validate only values that have been
>> changed"?
>
> Ah, I getcha.
> I think the solution here would be to use different forms for the "add
> profile" and the "edit profile" functions.
> The first has the Unique constraint, the second doesn't.
>
> An easy way to reuse the same basic form, if the only difference is
> the constraint, would be something like this:
>
> edit.yml
> ===
> elements:
>    - name: username
>
>
> add.yml
> ===
> load_config_file: 'edit.yml'
> constraints:
>    - type: 'DBIC::Unique'
>      name: username
>
> Will this work for you?
> Carl

Hi,

I've been using just a single form for both add and edit, using the
self_stash_key option from H::F::C::DBIC::Unique. The idea is that you
put the DBIC row object being edited onto the Catalyst stash and then
name that stash key in the form config. The uniqueness constraint will
ignore this one object if it's on the stash. A simplified (but
working) example from our project:

  - type: Text
    name: date
    label: Visit Date
    constraints:
      - Required
      - type:    DBIC::Unique
        resultset:   Visit
        self_stash_key:  object
        message: This visit already exists
        others:  patient_id

In this case the 'visit' object being edited is put on the stash under
the 'object' key (this example also illustrates including 'patient_id'
as a unique constraint, alongside 'date'; i.e. only one visit per
patient per date). There are formatting constraints I've omitted here
for the sake of clarity.

Cheers,

Tim