PHP Convert variable names to lowercase?

Question

I have an api listener script which takes in get parameters. But I seem to be having issues when users tend to pass mixed case variable names on the parameters.

For example:

http://mylistenerurl.com?paramName1=Hello&paramname2=World

I need my listener to be flixible in such a way that the variable names will be interpreted case-insensitively or rather still all in lower case like after I process the query string on some function, they are all returned as lower-cased variables:

extract(someFunction($_GET));
process($paramname1, $paramname2);

Can anybody shed some light on this?

*much appreciated. thanks!

Answer 1

This should do the trick:

$array_of_lower_case_strings = array_map( "strtolower", array( "This Will Be ALL lowercase.", ... ) );

So in your case:

$get_with_lowercase_keys = array_combine(
    array_map( "strtolower", array_keys( $_GET ) ),
    array_values( $_GET )
);

One thing I'll mention is you should be VERY careful with extract as it could be exploited to allow unexpected variables to be injected into your PHP.

Answer 2

Apply to your global variables ($_GET, $_POST) when necessary:

e.g. setLowerCaseVars($_GET); in your case

function setLowerCaseVars(&$global_var) {
    foreach ($global_var as $key => &$value) {
        if (!isset($global_var[strtolower($key)])) {
            $global_var[strtolower($key)] = $value;
        }
    }
}

Edit: Note that I prefer this to using array_combine because it will not overwrite cases where the lower-case variable is already set.