PHP Classes

lerro

I looked at this code here about creating classes

<?php
class Item {
  protected $name, $price, $qty, $total;

  public function __construct($iName, $iPrice, $iQty) {
    $this->name = $iName;
    $this->price = $iPrice;
    $this->qty = $iQty;
    $this->calculate();
  }

  protected function calculate() {
    $this->price = number_format($this->price, 2);
    $this->total = number_format(($this->price * $this->qty), 2);
  }

  public function __toString() {
    return "You ordered ($this->qty) '$this->name'" . ($this->qty == 1 ? "" : "s") .
    " at \$$this->price, for a total of: \$$this->total.";
  }
}

echo (new Item("Widget 22", 4.90, 2));
?>

http://php.net/manual/en/language.oop5.php

What i would like to know is that in this example, there is the function "__tostring()" which prints out the message to screen.

However, in the MVC architecture, it seems to be that

Class - is the model with only functions that return a calculation
logic - is in the Controller file which calls classes and controls logic
display - is in the view file which displays information to teh user.

So, where would such text really be stored to create a neat separation between model, logic and view?

1 - Simply, where is the best place to put text that will be displayed to the user?
Is it in the logic file or view file?

2 - The second question is that if the text to display is to be made editable by the administrator, how does one go about creating and linking a file that contains all messages so that instead of having "You ordered .....", say a variable can be used so that the adminitrator can set that text to whatever preference is desired, say "You purchased...." and possibly when language support is used, the language file enabled can contain the variables with the matching language.

Res

Personally I think that is a bad use of toString, as it's outputting display content. As you've noted by your questions, that doesn't give a very nice separation of business/presentation logic.

I think it's more common that the toString function return a serialized string of the object.

To answer your question though, you would want to create a separate system to handle the display of the content, using class members to indicate what kind of presentation logic should be displayed. Ideally your classes should just be dealing with data. Then you have two scripts, one that handles the business end of things, creates the objects, gathers data, sets variables that feed to the display. The second would be the display script, included by the script responsible for the business logic.

Quick example:

//orders.inc.php
$customer_orders = new Orders($customer_id);
$customer_orders->getCustomerOrder($order_id);

//orders.php - the display
if(is_array($customer_orders->order_details)){

   if($customer_orders->order_details['status'] == 1){
      echo "Order ".$customer_orders->order_details['order_id']." is in our system!";
   }elseif($customer_orders->order_details['status'] == 1){
      echo "Order ".$customer_orders->order_details['order_id']." is in our system and has been picked!";
   }

}

This is a very rough example/idea, but essentially you want to create a physical separation of how the data is pulled, and how it is displayed.

Later you can build a Content Management System, where similar to how you store information about a customer or an order, you would be storing the text that gets displayed under a certain circumstance. That gets a little trickier, it works well for things like articles, but element level text it can be a headache to keep track.

Res

Take a look at how Smarty template system has been setup, that is one popular way production servers accomplish the separation. Smarty itself may not be applicable to your project, but the fundamentals Smarty employs should be.

lerro

Thanks