PHP default website variables

Question

I'm attempting to come up with the best way to use default variables and override them if a $_GET is passed via the URL. Right now, I only have two, but I'll be adding more as I develop the site. Is there a better way?

I'm using define to define the variable and isset to determine if a variable is set and is not NULL.

define("THEME", "atom");
define("VERSION", "1.00");

if(isset($_GET["theme"]))
{
    $theme = $_GET["theme"];
} else
{
    $theme = THEME;
}
if(isset($_GET["version"]))
{
    $version = $_GET["version"];
} else
{
    $version = VERSION;
}

UPDATE I decided on the following. I'm storing my site settings in settings.php:

$settings = array();
$settings['theme'] = 'default';

Then I include that file, use the ternary operator, and then define the variable:

include_once('settings.php');

$theme = (isset($_GET["theme"])) ? $_GET["theme"] : $settings['theme'];
define("THEME", $theme);

JOpuckman · Accepted Answer · 2011-11-21 21:44:03Z

3

You can use ternary operators to lessen your typing.

$theme = (isset($_GET["theme"])) ? $_GET["theme"] : THEME;
$version= (isset($_GET["version"])) ? $_GET["version"] : VERSION;

answered Nov 21, 2011 at 21:44

JOpuckman

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2 Comments

pritaeas Over a year ago

I prefer to use isset() && !empty($_GET['theme'])

Xeoncross Over a year ago

This is not safe, you should not only check that it is set - you must also make sure it is valid so a hacker doesn't insert something bad. While you are at it, make sure it's a string/int too!

Xeoncross · Accepted Answer · 2011-11-21 21:42:48Z

2

I would do it the other way.

//$theme = config('default.theme');
//$version = config('default.theme_version');
// or
$theme = 'default';
$version = '1.00';

if(isset($_GET["theme"]) AND is_valid_theme($_GET['theme']))
{
    $theme = $_GET["theme"];
}

if(isset($_GET["version"]) AND is_valid_version($_GET['version']))
{
    $version = $_GET["version"];
}

define("THEME", $theme);
define("VERSION", $version);

answered Nov 21, 2011 at 21:42

Xeoncross

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2 Comments

w0lf42 Over a year ago

can you expand on your use of $variable = config('default.variable');? I think this looks like a good way to store site specific variables. Is this a custom ini file? THX

Xeoncross Over a year ago

@w0lf42, most frameworks have some kind of configuration loading. config() could load a JSON/XML/INI/YAML/PHP array file to find the default.

Alex Turpin · Accepted Answer · 2011-11-21 21:44:12Z

1

You could always do something like this:

$defaults = array(
    "theme" => "atom",
    "version" => "1.00"
);

$parameters = array_merge($defaults, $_GET);
extract($parameters);

I first set up an associative array for the default values. I then merge it with the $_GET array using array_merge. Since I mention $_GET as the second parameter, it will override the values if they exist. That way, you get an associative array of parameters. If you want to use them as local variables, you can use extract.

answered Nov 21, 2011 at 21:44

Alex Turpin

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Comments

k4t434sis · Accepted Answer · 2011-11-21 22:00:20Z

0

I would use either a switch or ternary statement here for clarity:

define("THEME", "atom");
define("VERSION", "1.00");

isset($_GET['theme'])   ? $theme = $_GET['theme']   : $theme = THEME;
isset($_GET['version']) ? $theme = $_GET['version'] : $theme = VERSION;

Whenever I know I may be later expanding a bit of logic like this I usually take the ternary approach. Keeps everything a bit more readable.

answered Nov 21, 2011 at 22:00

k4t434sis

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