设置无法从解析请求中识别的参数

Question

This has been playing on my mind for a while, I need to check that the user has entered the correct parameters, how do I do check this in an if statement in php? Users enters as follows;

www.domain.com/?amnt=100&from=AAA&to=BBB

so I need to check if they enter something as follows;

www.domain.com/?xxx=100&yyy=AAA&to=BBB

/////// Code is now as follows;

    //1000 Required parameter is missing
if ($amnt == null || $from==null || $to==null) {
    $error_code = 1000;
    $returnXML = new XML();
    $returnXML->CreateError($error_code,$error_msg[$error_code]);
    echo '<META HTTP-EQUIV="Refresh" Content="0; URL=error.xml">';
    exit;
}
//1100 Parameter not recognized
if(!isset($_GET['amnt'], $_GET['from'], $_GET['to']))
{
    $error_code = 1100;
    $returnXML = new XML();
    $returnXML->CreateError($error_code,$error_msg[$error_code]);
    echo '<META HTTP-EQUIV="Refresh" Content="0; URL=error.xml">';
    exit;
}

it returns the first IF when I request ../?xxx=100&yyy=GBP&to=USD, it makes logical sense, but how do I get it to return the second IF, if the parameters are not entered?

Answer 1

Using isset, you can check if the user has supplied the required GET parameters:

if(!isset($_GET['xxx'], $_GET['yyy'], $_GET['to']))
{
    // user has not supplied required parameters
}