Dynamic access of a PHP object variable

knapsack3

Hi,

I have a PHP object whose structure is like this:

The name of the object is 'Emp' and the attributes are:
name
age
sex
department
address

Now I have a function to get the data of Emp. The function is like this:

getEmpDetail(fieldname){
//return the requested data - fieldname can be anything from the above 5 attributes
}

Inside the above function, when I try to say

return (Emp.eval(fieldname))             or
return (Emp[fieldname])

it is not working.

Can you please tell me how to access this object's attribtues dynamically.

Thanks in advance.

bpat1434

Okay, but inside the object, how are all the items stored? As an example, here's something very short:

<?php

class Employer {
    var $emp; // To hold the object values...
    var $attributes; // To hold what attributes are valid
    var $errors; // To hold errors....

function __construct() {
    $this->emp = array();
    $this->attributes = array('name', 'age', 'sex', 'department', 'address');
}

function setAttribute($name, $val=null) {
	if(is_array($name)) {
        foreach($name as $key=>$val) {
            if(in_array($key, $this->attributes)) { $this->emp[$key] = $val; }
            else { $this->errors[] = $key . ' is not an allowed attribute.'; }
        }
    }
    if(!in_array($name, $this->attributes)) { return false; }
    else
        $this->emp[$name] = $val;

    return true;
}

function getAttribute($name) {
    if(!in_array($name, $this->attributes)) { return 'Unavailable attribute "' . $name . '"'; }
    if(!key_exists($name, $this->emp)) { return 'Unknown attribute "' . $name . '"'; }
    return $this->emp[$name];
}
}

// Instantiate a new Employer object:
$Emp = new Employer();
$Emp->setAttribute('name', 'bpat1434');
$Emp->setAttribute('sex', 'Male');
$Emp->setAttribute('department', 'PHPBuilder');
$Emp->setAttribute('age', '23');
$Emp->setAttribute('address', '123 Memory Lane');

// Get any one of the attributes....
echo $Emp->getAttribute('name');

echo '<hr>';

// Reset the attributes to something else...
$Emp->setAttribute(array('name'=>'knapsack3', 'age'=>'Unknown', 'sex'=>'Unknown', 'address'=>'PHPBuilder :: General Help', 'department'=>'PHP'));

// Get one of the new attributes...
echo $Emp->getAttribute('name');

?>

That works. I hope that example is enough for you.

knapsack3

Hi,

I am sorry. The requirement is that I should access this PHP object from a javascript.
Can you please suggest how to do it.

Thanks.

bpat1434

Ah.... well that's a whole different ball-game.... you can't directly influence PHP code with Javascript code. To do that, you'd need to either use AJAX (look at jQuery or Prototype frameworks) or have javascript call a PHP page to set the items.

Javascript (a client-side language) can't do anything with a PHP (server-side language) object; unless, that object is sent to Javascript via JSON or some other method.

knapsack3

Hi,

Thanks.

So what I have now done is I get the object as a JSON object, the structure remains the same as above.
I pass this JSON object to a method in javascript and set it to a local variable (say tmpObj)
Now I access the tmpObj's attributes dynamically.
I tried
a = tmpObj.eval(fieldname);
a = tmpObj[fieldname]

but all these don't work and eval() throws an error in IE.
Pls let me know your comments.

Thanks.

bpat1434

This is now a javascript issue, and I'm not hip to the dive with JS right now.... well, not as much as others 😉

Moved to a more appropriate forum.

knapsack3

I have found a solution for this. We can use

tmp = eval( "(tmpObj." + fieldname+ ")");

This will fetch the value dynamically.