Trouble converting NVP string to array..?

PHP provides a function to do this called: parse_str.

Note: It handles 'url encoded' characters correctly according to the example in the manual.

As usual, this turned into rather more complex than i first thought. ;-/

Hmm, this is 'quite fragile' as a function - for example you cannot 'urlencode' the entire string and have parse_str decode it as the the same NVP's. However, you can 'urlencode()' any _name_value_pair_ and it will decode them correctly. This function is 'useful' but not as general as i wish.

1) The array characters '[' and ']' are used by PHP in a special manner.
2) The parameters may just be normal NVP's e.g. 'Param01=PlainText'
3) The parameter may be URL encoded. e.g. %3CParam42_URLEncodedWithSpecialChars%3E%3DThisIs42%21

First, parse_str handles all the above formats but the array entries produced are not of a 'consistent' format.

This code attempts to accept the various NVP formats in one string and produce sensible outputs. This should make it of 'general' use.

Tested code: PHP 5.3.18 Source Code at Pastebin.com

The function that parses the NVP string:

function NVPToArray($NVPString) { // replacement for the original
    $parsed = array();
    parse_str($NVPString, $parsed);

    // convert it to an an associated array with the required formats:
    $nvpArray = array();
    foreach($parsed as $parsedName => $parsedValue) {
        if (is_array($parsedValue)) {
            $nvpName = $parsedName .'['. key($parsedValue) .']';
            $nvpValue = current($parsedValue);
        }
        elseif (empty($parsedValue)) { // was url encoded
            $parsedKeyAndValue = explode('=', $parsedName);
            $nvpName = $parsedKeyAndValue[0];
            $nvpValue = $parsedKeyAndValue[1];
        }
        else {
            $nvpName = $parsedName;
            $nvpValue = $parsedValue;
        }

        $nvpArray[$nvpName] =  $nvpValue;
    }
    return $nvpArray;
}

Here is some sample code that uses the function and displays the output:

Data:

$p1 = 'ParamNoLength=PlainTextIsItAnArray';
$p2 = 'ParamNoLengthUrlEncoded=EncodedTextIsItAnArray';
$p3 = '<Param42_URLEncodedWithSpecialChars>=ThisIs42!';

$src = 'BUTTONSOURCE[18]=AngellEYE_PHPClass&VERBOSITY[4]=HIGH'
       .'&'. $p1
       .'&'. urlencode($p2)
       .'&'. urlencode($p3);

Code:

$nvpArray = NVPToArray($src);

echo '<br />Input NVP string:<pre>';
var_dump($src,  __FILE__.__LINE__);
echo '</pre>';

echo '<br />Output:<pre>';
var_dump($nvpArray,  __FILE__.__LINE__);
echo '</pre>';

Input data:

'BUTTONSOURCE[18]=AngellEYE_PHPClass&VERBOSITY[4]=HIGH&ParamNoLength=PlainTextIsItAnArray&ParamNoLengthUrlEncoded%3DEncodedTextIsItAnArray&%3CParam42_URLEncodedWithSpecialChars%3E%3DThisIs42%21'

Output :

array
  'BUTTONSOURCE[18]' => string 'AngellEYE_PHPClass' (length=18)
  'VERBOSITY[4]' => string 'HIGH' (length=4)
  'ParamNoLength' => string 'PlainTextIsItAnArray' (length=20)
  'ParamNoLengthUrlEncoded' => string 'EncodedTextIsItAnArray' (length=22)
  '<Param42_URLEncodedWithSpecialChars>' => string 'ThisIs42!' (length=9)