How to get the query string in PHP with the PHP built-in server?

Question

I'm developing an MVC web app, and for its router to function I need to parse the query string, for which I need to load the URL into a variable in the first place. How do I achieve this with the PHP's built-in server?

I use PHP 7.3.9 at the moment, but as far as I can tell, the issue is persistent across all versions of a built-in server.

If I use Apache to run this app, everything is simple, all I need to do is

$uri = $_SERVER['QUERY_STRING']; and I'm good to go, everything works just fine.

However, if I use PHP's built-in web server, I get an error saying:

Undefined index: QUERY_STRING in /path_to_my_project/public/index.php on line 22

I tried googling around and found this pull request suggesting that such a variable truly doesn't exist in the PHP's built-in web server.

So my question is: how do I obtain the query string for my router if I run the built-in server, where $_SERVER['QUERY_STRING'] doesn't exist?

Answer 1

You can get the same result by using REQUEST_URI, if this is available:

function getServerQueryString()
{
    if(isset($_SERVER['QUERY_STRING']))
    {
        return $_SERVER['QUERY_STRING'];
    }
    elseif(isset($_SERVER['REQUEST_URI']))
    {
        $xpl = explode('/', $_SERVER['REQUEST_URI']);

        $baseName = $xpl[array_key_last($xpl)];

        if(strpos($baseName, '?') !== false)
        {
             return substr($baseName, strpos($baseName, '?')+1);
        }
    }

    return null;
}

echo $uri = getServerQueryString();

Some examples:

pageName.php?par1=val1&par2=val2...
// Output:
par1=val1&par2=val2...

pageName.php?
// Output:
     // empty

/some/path
// Output:
     // empty

Answer 2

$_SERVER['QUERY_STRING'] is only present when there is actually a query string on the request. You can avoid this issue by using array_key_exists():

if (array_key_exists('QUERY_STRING', $_SERVER)) {
    $uri = $_SERVER['QUERY_STRING'];
} else {
    $uri = '';
}

Or isset():

if (isset('QUERY_STRING', $_SERVER)) {
    $uri = $_SERVER['QUERY_STRING'];
} else {
    $uri = '';
}

Or (simplest) via the null coalesce operator:

$uri = $_SERVER['QUERY_STRING'] ?? '';

Note that you're probably getting this error on Apache too, you just don't notice it because it doesn't normally get dumped to the console.