Undefined index error in Cakephp - php

Question

I am running an Ajax tutorial example and a line gives error in controller file. What I'm doing is if a field is blank and user blurs out of it an error will display below the field.
Here is the whole function in MessagesController.php
public function validate_form()
{
if($this->RequestHandler->isAjax())
{
$this->request->data['Message'][$this->request->params['form']['field']] = $this->request->params['form']['value'];
$this->Message->set($this->request->data);
if($this->Message->validates())
{
$this->autoRender = FALSE;
}
else
{
$error = $this->validateErrors($this->Message);
$this->set('error', $error[$this->request->params['form']['field']]);
}
}
}
The error line is this:
$this->request->data['Message'][$this->request->params['form']['field']] = $this->request->params['form']['value'];
And error is this
Undefined index: form [APP\Controller\MessagesController.php, line 30]
Actually the tutorial was based on previous version of Cake but I have made proper changes compatible with current version but still error shows. Can someone please tell me what might be wrong in this line or elsewhere in the code. Thanks a lot.

Answer 1

$this->request->params does not contain a form index.
I think you should be looking at your $this->request->data?
$this->request->params has only information about your request: the action, the controller, any named parameters and so on.
The error you get is actually normal.
Add comment with link to tutorial.