Variables With Fat-Free Framework

Variables defined in Fat-Free are global. They can be accessed by any MVC component. Framework globals are not identical to PHP globals. Fat-Free variables accept all PHP data types, including objects and anonymous function.

To assign a value to a Fat-Free variable:

$f3->set('var', 'value');

To set several variables at once:

$f3->mset(
	array(
		'foo' => 'bar',
		'baz' => 123
	)
);

To retrieve the value of a framework variable named var :-

$f3->get('var');

To remove a Fat-Free variable from memory if no longer need it:

$f3->clear('var');

To find out if a variable has been previously defined :

$f3->exists('var');

Now we will practice those, first clean up you index.php file if you need. and a new routing like below::

$f3->route('GET /apple',
    function($f3) {
        $f3->set('color', 'Green');
        echo "{$f3->get('color')} apples. <br>";

        $f3->mset(
            array(
                'quality' => "Red",
                'quantity' => 3
            )
        );

        if($f3->exists('quality')) {
            echo "{$f3->get('quantity')} {$f3->get('quality')} apples. <br>";
        }

        $f3->clear('quantity');
        if($f3->exists('quantity')) {
            echo "{$f3->get('quantity')} apples. <br>";
        }
    }
);

output at url:: http://localhost/helloworld/apple is ::

Green apples.
3 Red apples.
Red apples.

In above example we are setting value by “set” and getting value by “get” function.
setting multiple value at once by “mset” function.
checking a given variable is exists or not by “exists” function.
And to removed the variable we used here “clear” function.

List of Fat-Free built-in framework variables:: System Variables

Use of framework variables is recommended, instead of PHP’s, to help you with data transfer across different functions, classes and methods. They also have other advantages:-

1) You can use framework variables directly in your templates.
2) You don’t have to instruct PHP to reference a variable outside the current scope using a global keyword inside each function or method. All F3 variables are global to your application.
3) Setting the Fat-Free equivalent of a PHP global like SESSION also changes PHP’s underlying $_SESSION. Altering the latter also alters the framework counterpart.

As a rule, framework variables do not persist between HTTP requests. Only SESSION and COOKIE (and their elements) which are mapped to PHP’s $_SESSION and $_COOKIE global variables are exempt from the stateless nature of HTTP.

Fat-Free framework variable names must start with an alpha character and should have no space and are case-sensitive.
Variable name may contain any number of letters, digits and underscores. WE can not use PHP reserved words as framework variable names.

Fat-Free has a number of helpful tools to work with framework variables::
Concatenation::

$f3->set('color', 'Green');
$f3->concat('color', ' and Red');
echo $f3->get('color');

output:: Green and Red

Copy::

$f3->copy('color', 'quality');
echo $f3->get('quality');

output:: Green and Red

Array operations::

$f3->set('colors', array('black', 'green', 'red'));
echo $f3->get('colors.1');

output:: green

$f3->push('colors','yellow');
echo $f3->get('colors.3');

output:: yellow

$f3->unshift('colors','purple');
echo $f3->get('colors.0');

output:: purple

echo $f3->shift('colors');

output:: purple

So in this post we get idea about Fat-Free framework variables.

Foysal Mamun

I am a student of Web Application Development courses at Google University.