HMVC中的用户输入验证

Question

After reading countless answers on this subject, i feel that i have still not found an unequivocal answer for the question - where and how should I do the user input validation in a (H)MVC? Going by the popular opinion i am partially sold on the idea of writing the validation code in MODEL , but that left the following two questions unanswered for me.

1) How does the MODEL know which UI element (eg:- textbox with id user_name) is responsible for error, so that it can make the VIEW to put the focus on that particular UI element or display an error message beside it ?

2) I read somewhere in SO that once you put the validation routines in MODEL , you could leverage the JS to place direct calls to those MODEL methods. In that case wouldn't it be like breaking the basic rules of MVC pattern?

If MODEL is not right place to accommodate the validation code, where would you suggest?

Please share your thoughts.

Thanks,

Answer 1

1) How does the MODEL know which UI element (eg:- textbox with id user_name) is responsible for error, so that it can make the VIEW to put the focus on that particular UI element or display an error message beside it ?

The model doesn't know (and doesn't need to know) which UI element is responsible. The Kohana ORM validation functions are designed to return an array of errors back to the controller, which the controller inserts into the view. The Kohana documentation has an example of exactly what you are trying to do.

2) I read somewhere in SO that once you put the validation routines in MODEL , you could leverage the JS to place direct calls to those MODEL methods. In that case wouldn't it be like breaking the basic rules of MVC pattern?

Kohana does not have any built-in JavaScript-based model validation. There are many add-on JavaScript validation frameworks you can use, and most of the common ones work by having you generate a list of class names, a special data-* attribute, or a JavaScript array in the server-side code, which is used by the client-side validation code. The proper way to generate this validation data is in the controller, by asking the model for an array of the validations that it performs and then using that array inside the controller to build the JavaScript.

The only difference between this technique and the one described above is that the former only asks the model for the names of failed validations while the latter asks the model for the names of all validations.

To do this, you will need to create a new class Validation extends Kohana_Validation and add a method to it get_rules that returns the validation rules for this object. Then, in the controller, you can call my_model->validation()->get_rules() and process the array of rules to make the JavaScript.