CakePHP HABTM data not saving to database

Question

I have a model GenForm which has a HABTM relationship with another model PdfFile. I use this to generate a list of checkboxes in my GenForm index view. In the GenForm model, I added:

public $hasAndBelongsToMany = array(
    'PdfFile' => array(
        'className' => 'PdfFile',
        'joinTable' => 'gen_forms_x_pdf_files'
    )

Here's a fragment from my GenForm index.ctp view:

<?php 
echo $this->Form->input( 'PdfFile', array('label' => 'Select some PDF files', 'multiple' => 'checkbox') );
echo $this->Form->input( 'first_name' );
echo $this->Form->input( 'last_name' );
?>

In the controller, I have a basic save:

    if ($this->request->is('post')) { // form was submitted
        $this->GenForm->create();
        if ($this->GenForm->save($this->request->data)) {
            return $this->redirect(array('action' => 'generate', $this->GenForm->id)); // assemble the PDF for this record
        } else {
            $this->Session->setFlash(__('Log entry not saved.'));
        }
    }

Now $this->data looks something like this when I debug() it:

array(
    'PdfFile' => array(
        'PdfFile' => array(
            (int) 0 => '1',
            (int) 1 => '5'
        )
    ),
    'GenForm' => array(
        'first_name' => 'xxx',
        'last_name' => 'xxx',
        'association_id' => '1',
        'email' => ''
    )
)

---

Everything works perfectly, but I couldn't validate the checkboxes (at least one must be checked). So, as per this answer, I made some changes.

The index.ctp view became:

<?php 
echo $this->Form->input( 'GenForm.PdfFile', array('label' => 'Select some PDF files', 'multiple' => 'checkbox') );
echo $this->Form->input( 'first_name' );
echo $this->Form->input( 'last_name' );
?>

Here's my validation rule:

public $validate = array(
    'PdfFile' => array(
        'rule' => array(
            'multiple', array('min' => 1)
        ), 
        'message' => 'Please select one or more PDFs'
    )
)

This is what $this->data looks like now:

array(
    'GenForm' => array(
        'PdfFile' => array(
            (int) 0 => '1',
            (int) 1 => '5'
        ),
        'first_name' => 'xxx',
        'last_name' => 'xxx',
        'association_id' => '1',
        'email' => ''
    )
)

Now the checkboxes for PdfFile validate, but the PdfFile data isn't saved -- although the other fields for GenForm are saved correctly to their own table.

Can anyone tell me what I'm missing so that PdfFile saves automatically and gets validated?

Answer 1

The first form is right

Stating the obvious, but the form that worked is the form to use i.e.:

echo $this->Form->input('PdfFile', array(
    'label' => 'Select some PDF files', 
    'multiple' => 'checkbox'
));

Changing the form to have a "field" named 'PdfFile' will simply not work - as the model layer will remove any data for fields that don't exist - and in this form it will check for gen_forms.PdfFile, find there is no field and ignore the data.

Validation

To take care of validation errors - use a validation rule running on the model which checks the number of habtm records to be saved. It doesn't matter what the name of the field used for validation is e.g.:

<?php
class GenForm extends AppModel {

    public $validate = array(
        'dummy' => array( // <- name this whatever you like
            'atLeastOne' => array(
                'required' => true, // run always
                'rule' => array('validateAtLeastOne')
            )
        )
    );

    function validateAtLeastOne() {
        if (!isset($this->data['PdfFile'])) {
            // there is no pdf data at all, ignore this rule
            // allow other save operations to work
            return true;
        }

        $return = count(array_filter($this->data['PdfFile']['PdfFile']));
        if (!$return) {
            $this->PdfFile->invalidate('PdfFile', 'Please upload a file');
        }
        return $return;
    }

}

Because the validation rule returns false if there are no records it will halt the save. By calling invalidate on the HABTM association with the same "field" name that the form helper will look for - an error message will be displayed.

Alternatively

You can use the second approach in the question:

echo $this->Form->input('GenForm.PdfFile', array(
    'label' => 'Select some PDF files', 
    'multiple' => 'checkbox'
));

In the full knowledge that this is not how cake expects to receive data and then manipulate it to be the right format in beforeValidate:

<?php
class GenForm extends AppModel {

    public $validate = array(
        'PdfFile' => array( // existing rule
            ...
        )
    );

    function beforeValidate() {
        if (isset($this->data[$this->alias]['PdfFile'])) {
            // keep the existing data as that's what validation will check against
            // copy to the right location so Cake will process it
            $this->data['PdfFile']['PdfFile'] = $this->data[$this->alias]['PdfFile'];
        }
        return true;
    }

    ...
}

Answer 2

If I remember correctly, from cake manual probably you are formatting the data wrongly.

Try that $this->data looks like this:

array(
    'GenForm' => array(
        'first_name' => 'xxx',
        'last_name' => 'xxx',
        'association_id' => '1',
        'email' => ''
    ),
    'PdfFile' => array(
        (int) 0 => '1',
        (int) 1 => '5'
    ),
)