Can I dynamically set my class properties?

PHP
1

Rather than write a huge list of properties used by a class I want to know if I can dynamically generate them when needed. I have looked and __set and __get but I am not sure how (or if) I use them with what I am trying to do.

The function I have at the moment is this (obviously doesn’t work):

public function getShowHelpingDetails($id) {                
$this->show_id = $id;        
$result = $this->selectRecord($this->table, $this->show_id, '*', '', 'show_');       
foreach ($result as $key => $value) {            
  $this->{$key} = $value;       
}            
}

And then trying to access the properties like this:

$h = new ShowHelping;
     $helping = $h->getShowHelpingDetails($show_id);
echo $helping->time;

Can anyone help me with this and if not possible advise of a better way to set my class properties without huge lists of them?

2

Take a look at http://www.sitepoint.com/forums/showthread.php?869163-Curious-Magic-Issue-(I-think)

ServerStorm utilized something very similar, and it had the ability to validate the property names in each class so you couldn’t just add new ones (kind of an added protection).

3

Thank you - I am reading through the thread now to see if I can get my head around it :slight_smile:

4

I am needing some more help as I have tried to use the information from that thread and apply it to my requirements but it still isn’t working and I am not sure I have done it correctly.

In my database class (as all classes extend it) I have put the following:

protected $properties = array();
    protected $allowed_props = array();

function __set($property, $value) {            
try {          
if(in_array($property, $this->allowed_props)) {              
$this->properties[$property] = $value;        
} 
else {           
 throw new CustomException("The $property is not allowed");        
}    
} catch (CustomException $e) {        
echo $e->getErrorReport();    
}     
 }    
// get defined property 
 function &__get($property) {        
return $this->properties[$property];        
}

  protected function getAllProperities() {        
return $this->properties;        
}

Then in my child class I have this (I haven’t changed the original function):

public function __construct() {                
parent::__construct(DB_SERVER, DB_USER, DB_PASS, DB_NAME);                
$this->allowed_props = array('id','show_id','help_text');    
}
public function getShowHelpingDetails($id) {                
$this->show_id = $id;        
$result = $this->selectRecord($this->table, $this->show_id, '*', '', 'show_');        
foreach ($result as $key => $value) {           
$this->$key = $value;        
}            
}

Edit: I forgot to say, I am just receiving the error ‘The $property is not allowed’ ($property shows the variable name)

5

Thanks to a response on another forum I now have this solved by adding a return from my function so the end function that worked (using the previous set and get code) is:

public function getShowHelpingDetails($id) {                
$this->show_id = $id;        
$result = $this->selectRecord($this->table, $this->show_id, '*', '', 'show_');        
foreach ($result as $key => $value) {           
$this->{$key} = $value;        
}  
return $this;          
}
6 

class TestObject {}

$t = new TestObject;
$t->newProp = "cat";

print $t->newProp;

Works, creates a public property.

Now for your current code, your try catch is all wrong you do not throw an exception with in a try block nor do you hand the error directly in your object that is throwing the exception.


class TestObject
{
  protected
    $properties    = array(),
    $allowed_props = array();

  function __set ( $property, $value )
  {
    $property = strtolower( $property );

    if ( in_array( $property, $this->allowed_props ) ) {
      $this->properties[ $property ] = $value;
      return $this;
    }
    
    throw new CustomException("The $property is not allowed.");
  }

  function __get ( $property ) {
    return $this->properties[ strtolower( $property ) ]; }
}