Model behavior trying to validate when it shouldn’t be - cakephp

Question

I’ve created a simple model behavior in my CakePHP application to handle file uploads. In its beforeValidate() method I have the following:
public function beforeValidate(Model $Model, $options = array()) {
$maxFileSize = '1MB';
$Model->validator()->add($this->settings[$Model->alias]['field'], array(
'extension' => array(
'rule' => array('extension', $this->settings[$Model->alias]['allowedExtensions']),
'message' => __('Please supply a valid image'),
'allowEmpty' => ($this->settings[$Model->alias]['required'] === false)
),
'fileSize' => array(
'rule' => array('fileSize', '<=', $maxFileSize),
'message' => __('Image must be less than %s', $maxFileSize)
),
'uploadError' => array(
'rule' => 'uploadError',
'message' => __('Something went wrong with the upload')
)
));
return true;
}
I’m dynamically adding file field-related validation. The first rule is checking the extension is in an allowed array of extensions passed in the behavior settings, and I’ve an allowEmpty key that equates to true because a file upload is not mandatory in this case.
This behavior is attached to an Event class. When editing an event, the extension validation rule kicks in, even though I’ve specified allowEmpty as true. Why is this?
Is it because the data passed in the file field is an array and actually equates to non-empty, therefore the validation is kicking in? If so, how can I combat this? I only want validation to kick in if a file has actually been uploaded.

Answer 1

Is it because the data passed in the file field is an array and actually equates to non-empty, therefore the validation is kicking in?
Yes. If no file is uploaded the array key for the model field will still be present, with a none-empty value. I.e. something like:
//$request->data
array(
'Model' => array(
'field' => array(
...
'size' => 0,
'error' => 4
)
)
);
Coping with optional file uploads
To prevent problems validating a field which is a file upload - a simple option is to check for UPLOAD_ERR_NO_FILE and wipe the relevant model data. In a beforeValidate callback that could look like this:
$field = $this->settings[$Model->alias]['field'];
if (
isset($Model->data[$Model->alias][$field]['error']) &&
$Model->data[$Model->alias][$field]['error'] === UPLOAD_ERR_NO_FILE
) {
unset($Model->data[$Model->alias][$field]);
}
Alternatively add a bail-early chunk of code to all validation rules:
function validateExt($Model, ...) {
$field = $this->settings[$Model->alias]['field'];
if ($Model->data[$Model->alias][$field]['error'] === UPLOAD_ERR_NO_FILE) {
return true;
}
...
}
Such that even if called with an empty file upload the validation rules do not return false negatives. Incidentally, validation rule-order matters, it would make more sense to check for an upload error - before validating the contents of the upload =).