PHP Convert variable names to lowercase?

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 l开发者_JAVA百科ike 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!

---

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.

---

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.

---

PHP has had a native function (array_change_key_case()) for this task since version 4.2 to change the case of first level keys. To be perfectly explicit -- this function can be used to convert first level key to uppercase or lower case BUT this is not a recursive function so deeper keys will not be effected.

Code: (Demo)

parse_str('paramName1=Hello&paramname2=World&fOo[bAR][BanG]=boom', $_GET);

var_export($_GET);

echo "\n---\n";
$lower = array_change_key_case($_GET);

var_export($lower);

Output:

array (
  'paramName1' => 'Hello',
  'paramname2' => 'World',
  'fOo' => 
  array (
    'bAR' => 
    array (
      'BanG' => 'boom',
    ),
  ),
)
---
array (
  'paramname1' => 'Hello',        # N changed to n
  'paramname2' => 'World',
  'foo' =>                        # O changed to o
  array (
    'bAR' =>                      # AR not changed because not a first level key
    array (
      'BanG' => 'boom',           # B and G not changed because not a first level key
    ),
  ),
)