Very useful article jonathan. I'm still stumbling around with CakePHP (not having any real projects to use it or the time the play). How about posting this to the wiki?

Good article. Another effective method around an age old problem.

You could also have a different error tag in your view for every possible validation error, so it can be more verbose:

$this->invalidate('passwordsDontMatch')

But I still think that using the beforeSave callback (along with all the predefined callbacks) is the way to go.

dont forget about beforeValidate() this will allow you to use both the simple method and any custom validation via invalidate(). I wrote a quick example to the google group a few weeks back.

Besides that...great stuff you are putting together on Cake.

Wow. Seems I need to give this a try. Jonathan, my object oriented programming is kind of weak. Should I avoid this at all costs? I like PHP but haven't worked with it at this level. What's your opinion?

As always, an informative article.

I have used beforeValidate() and invalidate() as gwoo suggests

http://groups.google.com/group/cake-php/browse_thread/thread/89acef2ed01dd7ee/e5fe6d771038e51a#e5fe6d771038e51a

Sorry, this is a little off topic for this article but…I thought you were a rails guy? Can you give a short talk on why you have chosen to use Cake? I'm very curious as I am thinking about learning it, or Django.

Can someone reading this (maybe Jonathan) speak to the display and styling of errors output by the validator?

I built a simple app with validation in the controller for the registration page. How can I get the form to essentially re-render and display errors at each input item when there are validation errors?

p.s.

I ask this question here because I come from a CSS/XHTML background when it comes to code (those are my forte) and I am an Information Architect by study, so I want to display errors with the form in question, not using back or simply displaying them at the top (or bottom) of a form.

Yesterday I downloaded cakephp, it seemed to be a nice framework (based on articles here at snook). The only problem I found was that they haven't included a template system. My current framwork is using flexy and it works pretty good. I just hate to write php and html in the same document, to many <?php ?> etc. RoR has liquid, how about cake?

Jonathan: Do you really think its no difference? I'v done 3-4 projects with template systems and I can't go back, the view code is much easier to read, especially when you have large view blocks. From smarty.php.net: "{$title} is less extraneous than <?php echo $title; ?>". Don't you agree with that?

@Emil,

One thing you will notice in cake is I have wrote the view class to allow an easy way to extend it. While I have no plans to add a templating system to cake itself, since PHP is a templating language. You are free to extend it and use your own.

I have never used flexy, but I did write a Smarty view class that should give you an start form impementing one for flexy, and I would suggest submitting it as a snippet on the CakeForge site where others my find it useful.

Smarty View class
http://cakeforge.org/snippet/detail.php?type=snippet&id=6

@jonathan,

If you plan to distribute your application I would suggest not using short tags, since some host may turn them off.

"RoR has liquid"

Emil, RoR is using eRuby for views, which is ruby embedded in html.

Liquid (which is a ruby port of the django templating) can be used as a plugin, and is basically only used when wanting to do some sort of theming...

Liquid was developed for the use of theming of individual Shopify shops... I dont know of many products/applications actually using liquid...

Ok, I'm sorry - never really tried RoR. Just got amazed over Shopify when it was in beta.

Larry & Jonathan: I'v started develop my own personal homepage/blog and I will do it without any template engine but with cake! I'll be back when I'v tried it for "real".

What I am asking myself is, how does cake handle the difference between an INSERT and an UPDATE? For example: I defined the password has to be filled, but by editing the form I don't want the user to fill in the password, just if he wants to.

I don't know where you got the idea that you can't declare more than one requirement per field. The following is perfectly valid:

class Profile extends AppModel
{
var $name = 'Profile';
var $validate = array(
'firstname' => VALID_NOT_EMPTY,
'lastname' => VALID_NOT_EMPTY,
'password' => VALID_NOT_EMPTY,
'email' => VALID_NOT_EMPTY,
'email' => VALID_EMAIL
);
}

Though unnecessary, just to demonstrate. You can use Cake's validation for anything, no need for custom functions.

I have written a custom validates routine that checks for any declared "validateFieldName()" functions and runs them, passing any error messages into an array called (doh!) $errorMessages. After all found functions are called, it checks to see if there's any messages in $errorMessages, and returns false (preventing the save operation) if there are some. If I wanted, I could have called the parent::validates function before returning anything, but I rarely use the $validate array for anything.

@Nick: That's nice if all you need is to check if the field is not empty or is a valid email. I use those constants in my validate functions too. But what about checking if someone is double-registering, of if the two password fields match.

Code igniter has a more flexible validation system. Not that I prefer CI, it's just that.

Cake for everyone!

Thanks mate,

You have saved my feeble brain. It will not be exploding today

:)

Invalidation from the controller did not work in 1.2. Saving the model clears fields in validationErrors array.

I solved this by setting new validation rules that fail with custom messages if I found in controller that data is not valid.

I seem to have a problem accessing $this->data[] in the model. Do you know what this issue could be?

Thanks, great work your doing here.

Say if you want to use $validates but not worry about every field in the $validates array being required. Do something along these lines in your model:

function beforeValidate(){

foreach($this->data['ModelName'] as $k => $v){
if(empty($v)){
unset($this->validate[$k]);
}
}

return true;
}

It will only validate when the field is not empty.

Regarding templating vs PHP tags (from June 26, 2006):

I came to PHP from Perl, so it was natural for me to think in terms of heredocs:

echo <<<HTML
<title>$title</title>
HTML;

While it doesn't deal with iteration or other "complex" coding, it does take care of all those finger-busting tags for simple variable substitution in large HTML blocks.