1 <?php

     2 

     3 /**

     4  * @file

     5  * Provides a helper to properly encode HTML-safe JSON prior to PHP 5.3.0.

     6  */

     7 

     8 /**

     9  * Encodes a PHP variable to HTML-safe JSON for PHP versions below 5.3.0.

    10  *

    11  * @see drupal_json_encode()

    12  */

    13 function drupal_json_encode_helper($var) {

    14   switch (gettype($var)) {

    15     case 'boolean':

    16       return $var ? 'true' : 'false'; // Lowercase necessary!

    17 

    18     case 'integer':

    19     case 'double':

    20       return $var;

    21 

    22     case 'resource':

    23     case 'string':

    24       // Always use Unicode escape sequences (\u0022) over JSON escape

    25       // sequences (\") to prevent browsers interpreting these as

    26       // special characters.

    27       $replace_pairs = array(

    28         // ", \ and U+0000 - U+001F must be escaped according to RFC 4627.

    29         '\\' => '\u005C',

    30         '"' => '\u0022',

    31         "\x00" => '\u0000',

    32         "\x01" => '\u0001',

    33         "\x02" => '\u0002',

    34         "\x03" => '\u0003',

    35         "\x04" => '\u0004',

    36         "\x05" => '\u0005',

    37         "\x06" => '\u0006',

    38         "\x07" => '\u0007',

    39         "\x08" => '\u0008',

    40         "\x09" => '\u0009',

    41         "\x0a" => '\u000A',

    42         "\x0b" => '\u000B',

    43         "\x0c" => '\u000C',

    44         "\x0d" => '\u000D',

    45         "\x0e" => '\u000E',

    46         "\x0f" => '\u000F',

    47         "\x10" => '\u0010',

    48         "\x11" => '\u0011',

    49         "\x12" => '\u0012',

    50         "\x13" => '\u0013',

    51         "\x14" => '\u0014',

    52         "\x15" => '\u0015',

    53         "\x16" => '\u0016',

    54         "\x17" => '\u0017',

    55         "\x18" => '\u0018',

    56         "\x19" => '\u0019',

    57         "\x1a" => '\u001A',

    58         "\x1b" => '\u001B',

    59         "\x1c" => '\u001C',

    60         "\x1d" => '\u001D',

    61         "\x1e" => '\u001E',

    62         "\x1f" => '\u001F',

    63         // Prevent browsers from interpreting these as as special.

    64         "'" => '\u0027',

    65         '<' => '\u003C',

    66         '>' => '\u003E',

    67         '&' => '\u0026',

    68         // Prevent browsers from interpreting the solidus as special and

    69         // non-compliant JSON parsers from interpreting // as a comment.

    70         '/' => '\u002F',

    71         // While these are allowed unescaped according to ECMA-262, section

    72         // 15.12.2, they cause problems in some JSON parsers.

    73         "\xe2\x80\xa8" => '\u2028', // U+2028, Line Separator.

    74         "\xe2\x80\xa9" => '\u2029', // U+2029, Paragraph Separator.

    75       );

    76 

    77       return '"' . strtr($var, $replace_pairs) . '"';

    78 

    79     case 'array':

    80       // Arrays in JSON can't be associative. If the array is empty or if it

    81       // has sequential whole number keys starting with 0, it's not associative

    82       // so we can go ahead and convert it as an array.

    83       if (empty($var) || array_keys($var) === range(0, sizeof($var) - 1)) {

    84         $output = array();

    85         foreach ($var as $v) {

    86           $output[] = drupal_json_encode_helper($v);

    87         }

    88         return '[ ' . implode(', ', $output) . ' ]';

    89       }

    90       // Otherwise, fall through to convert the array as an object.

    91 

    92     case 'object':

    93       $output = array();

    94       foreach ($var as $k => $v) {

    95         $output[] = drupal_json_encode_helper(strval($k)) . ':' . drupal_json_encode_helper($v);

    96       }

    97       return '{' . implode(', ', $output) . '}';

    98 

    99     default:

   100       return 'null';

   101   }

   102 }