[Catalyst] Putting more in the View

[Wade.Stuart at fallon.com]

> In the 'traditional' manner, the /user/save/33 Controller would take the
> request->params and validate them. If valid the relevent user record
> would be updated and that would be the end of it. If invalid however we
> need to display an error message and re-populate the form with the
> additions or modifications made by the user so they can correct them. In
> other words sticky-forms.
>
> This is where I have my first problem. I can't now pass the user object
> back to the Template, I need to pass the request->params to the
> template. I can either try to build up a CDBI::User object from the
> request->params and pass that to the Template (which does not work since
> CDBI cannot create a new object without writing it to the database. I
> understand that DBIC can do this but I have not yet gone down this
> route.). Or I can refrain from passing in a CDBI::User object to the
> Template in the first place but instead pass in all the parts of the
> user object separately to the stash.

Are you using the FillInForm plugin? This provides sticky form
functionality.  It also ties well with DFV.

I do not understand were you are struggling with the user object being
passed anywhere.  Because the form has invalid data, the user object has
not been modified and the form is shown again for the end user to correct.
Why even try to pass the user object around?

> I hope you are following this. Sorry for the long post but I am getting
> to the important bit now...
>
> These are the relevent bits of code.
>
> 1. Decompose a User object into separate stash variables.
> 2. Put the stash variables into the form (this is done with TT).
> 3. Do simple validation when the form is submitted, e.g. ensure that
> mandatory fields are filled in.
> 4. Do simple manipulation of data, e.g. remove leading and trailing
> whitespace, convert checkboxes into true/false values, date formats etc.
> 5. Do database validation. e.g. is this username already taken
> 6. Compose a User object from the input data from (4) if the validation
> succeeds.
> 7. If validation fails, take the raw request->params (prior to (4)) and
> re-populate the form.
>

1: why do this at all stash and TT both handle complex vars?


DFV && FillInForm.

> In my previous experience, and in many of the examples I have seen,
> steps 1,3,4,6 and 7 (and often 5 as well) takes place in the
controller....
>
> My reasoning is that 1,2,3,4 and 7 rightfully belong in the View not the
> Controller. 5 and 6 should be in the Controller/Model.

1: does not need to be done.
2: this is already in your V, as TT [% %] blocks.
3: this is either C or M.  Validation has little to nothing to do with the
view.
4,5,6: C and/or M this has nothing to do with view.
7: C and V,  or nothing if you are using DFV and FillInForm.

>
> To this end I have developed my Catalyst application along these lines.
>
> I have a Myapp::V::User->objectDecompose method that takes the User
> object passed to it from the URI /user/edit/33 code and puts the bits
> that the view needs into the Template. (Step 1)
>
> I have MyApp::V::User->validate which takes the request->params and
> validates them (Step 3 and 4) and, on the assumption that the validation
> might fail, also implements the sticky-form (Step 7).

this is silly,  what does validation against business rules or database
rules have to do with view.

>
> This leaves my controller fairly clean and easier to implement with all
> the messy validation and data transfer taking place in the View where in
> my opinion is should be.
>
> I welcome any comments on this approach.