JSON 函数
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PHP手册

json_encode

(PHP 5 >= 5.2.0, PECL json >= 1.2.0)

json_encode — 对变量进行 JSON 编码

说明

string json_encode ( mixed $value )

返回 value 值的 JSON 形式 或者在失败时返回 FALSE

参数

value

待编码的 value ，除了resource 类型之外，可以为任何数据类型

该函数只能接受 UTF-8 编码的数据（译注：指字符/字符串类型的数据）

返回值

编码成功则返回一个以 JSON 形式表示的 string 或者在失败时返回 FALSE。

更新日志

版本 说明
5.4.0 JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, and JSON_UNESCAPED_UNICODE options were added.
5.3.3 JSON_NUMERIC_CHECK option was added.
5.3.0 The options parameter was added.

范例

Example #1 A json_encode() 的例子

<?php
$arr = array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);

echo json_encode($arr);
?>

以上例程会输出：

{"a":1,"b":2,"c":3,"d":4,"e":5}

注释

Note:

In the event of a failure to encode, json_last_error() can be used to determine the exact nature of the error.

Note:

When encoding an array, if the keys are not a continuous numeric sequence starting from 0, all keys are encoded as strings, and specified explicitly for each key-value pair.

参见

JSON 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 对变量进行 JSON 编码

用户评论:

craig at craigfrancis dot co dot uk (18-Mar-2012 11:34)

If your on a version of PHP before 5.2, this might help:

<?php
if (!function_exists('json_encode')) {
    function json_encode($data) {
        switch ($type = gettype($data)) {
            case 'NULL':
                return 'null';
            case 'boolean':
                return ($data ? 'true' : 'false');
            case 'integer':
            case 'double':
            case 'float':
                return $data;
            case 'string':
                return '"' . addslashes($data) . '"';
            case 'object':
                $data = get_object_vars($data);
            case 'array':
                $output_index_count = 0;
                $output_indexed = array();
                $output_associative = array();
                foreach ($data as $key => $value) {
                    $output_indexed[] = json_encode($value);
                    $output_associative[] = json_encode($key) . ':' . json_encode($value);
                    if ($output_index_count !== NULL && $output_index_count++ !== $key) {
                        $output_index_count = NULL;
                    }
                }
                if ($output_index_count !== NULL) {
                    return '[' . implode(',', $output_indexed) . ']';
                } else {
                    return '{' . implode(',', $output_associative) . '}';
                }
            default:
                return ''; // Not supported
        }
    }
}
?>

webmaster_php at colnect dot com (22-Feb-2012 11:52)

WARNING! Do not pass associative arrays if the order is important to you. It seems that while FireFox does keep the same order, both Chrome and IE sort it. Here's a little workaround:

        $arWrapper = array();       
        $arWrapper['k'] = array_keys($arChoices);
        $arWrapper['v'] = array_values($arChoices);
        $json = json_encode($arWrapper);

pahreg at inbox dot ru (04-Feb-2012 06:36)

Simple replacement for JSON_UNESCAPED_UNICODE (PHP < 5.4 for example)
 
Can be buggy, but works for simple UTF-8 strings.

<?php
$json = preg_replace_callback('/\\\u(\w\w\w\w)/',
    function($matches)
    {
        return '&#'.hexdec($matches[1]).';';
    }
    , json_encode($array));
?>

julien dot dev at gmail dot com (25-Jan-2012 02:08)

Guys, (and girls)

A trick to unescape UTF8 for ppl with php < 5.4.0

json_encode(...) gives you \u..... right ?

json_decode DOES unescape though !

so:

/* Imagine you have an object like this :
[{"name":"php help héhéhahéhé","url":"http://payAttention.com"},{"name":"took me brainack j'étais mal mec","url":"http://slashesEscapingSux"}]
*/

//first encode your object
$myDirtyString = $json_encode($myObject);

/*the JSON_UNESCAPED_SLASHES, and JSON_UNESCAPED_UNICODE being unavailable, you'll have some ugly escaping happening :

[{"name":"php help h\u00e9h\u00e9hah\u00e9h\u00e9","url":"http:\/\/payAttention.com"},{"name":"took me brainack j'\u00e9tais mal mec","url":"http:\/\/slashesEscapingSux\/"}]
*/

//So, you'll have to unescape slashes:
$myDirtyString = str_replace("\/","/",$myDirtyString);

//Then, for the trick, escape doule quotes
$myDirtyString = str_replace('"','\\"',$myDirtyString);

//in oder to json_decode this trciked string (and get your utf8 unescaped)

$myCleanedString = json_decode('"'.$myDirtyString.'"');

// Je tour est joué !
// There might be better ways to do it but i found so much useless nonsense on forums that i decided to go with it for tonight

bohwaz (24-Nov-2011 01:05)

Are you sure you want to use JSON_NUMERIC_CHECK, really really sure?

Just watch this usecase:

<?php
// International phone number
json_encode(array('phone_number' => '+33123456789'), JSON_NUMERIC_CHECK);
?>

And then you get this JSON:

{"phone_number":33123456789}

Maybe it makes sense for PHP (as is_numeric('+33123456789') returns true), but really, casting it as an int?!

So be careful when using JSON_NUMERIC_CHECK, it may mess up with your data!

me (17-Nov-2011 07:17)

::fast utf8-encoding of strings::

json_encode( array_map( function($t){ return is_string($t) ? utf8_encode($t) : $t; }, $array ) )

spm at bf-team dot com (09-Nov-2011 07:29)

json and utf8?

Fast Easy Method:)

Encode: json_encode(array_map('base64_encode', $array));

Decode: array_map('base64_decode', json_decode($array);

mmi at uhb-consulting dot de (08-Nov-2011 03:59)

When you have trouble with json_encode and German umlauts. json_encode converts Strings to NULL when detecting umlauts not being UTF8encoded.

Here's another recursive UTF8 conversion function and vice-versa. The object handling might be buggy but works for me.

<?php
function array_utf8_encode_recursive($dat)
        { if (is_string($dat)) {
            return utf8_encode($dat);
          }
          if (is_object($dat)) {
            $ovs= get_object_vars($dat);
            $new=$dat;
            foreach ($ovs as $k =>$v)    {
                $new->$k=array_utf8_encode_recursive($new->$k);
            }
            return $new;
          }
         
          if (!is_array($dat)) return $dat;
          $ret = array();
          foreach($dat as $i=>$d) $ret[$i] = array_utf8_encode_recursive($d);
          return $ret;
        }
function array_utf8_decode_recursive($dat)
        { if (is_string($dat)) {
            return utf8_decode($dat);
          }
          if (is_object($dat)) {
            $ovs= get_object_vars($dat);
            $new=$dat;
            foreach ($ovs as $k =>$v)    {
                $new->$k=array_utf8_decode_recursive($new->$k);
            }
            return $new;
          }
         
          if (!is_array($dat)) return $dat;
          $ret = array();
          foreach($dat as $i=>$d) $ret[$i] = array_utf8_decode_recursive($d);
          return $ret;
        }
?>

yangmuxiang at gmail dot com (28-Oct-2011 12:28)

I use base64_encode, it works fine.

<?php
 $a = array('msg' => '中文');

 $a['msg'] = base64_encode($a['msg']);

 $json = json_encode($a);

 echo $json;

 $b = json_decode($json) ;
 echo base64_decode($b->msg);
?>

rob at weeverapps dot com (26-Sep-2011 05:15)

If, for some reason you need to force a single object to be an array, you can use array_values() -- this can be necessary if you have an array with only one entry, as json_encode will assign it as an object otherwise :

<?php
$object[0] = array("foo" => "bar", 12 => true);

$encoded_object = json_encode($object);
?>

output:

{"1": {"foo": "bar", "12": "true"}}

<?php $encoded = json_encode(array_values($object)); ?>

output:

[{"foo": "bar", "12": "true"}]

devilan (REMOVEIT) (at) o2 (dot) pl (15-Sep-2011 08:39)

For PHP5.3 users who want to emulate JSON_UNESCAPED_UNICODE, there is simple way to do it:
<?php
function my_json_encode($arr)
{
        //convmap since 0x80 char codes so it takes all multibyte codes (above ASCII 127). So such characters are being "hidden" from normal json_encoding
        array_walk_recursive($arr, function (&$item, $key) { if (is_string($item)) $item = mb_encode_numericentity($item, array (0x80, 0xffff, 0, 0xffff), 'UTF-8'); });
        return mb_decode_numericentity(json_encode($arr), array (0x80, 0xffff, 0, 0xffff), 'UTF-8');

}
?>

1rsv dog mail point ru (12-Sep-2011 12:19)

Some time you may need to encode a javascript function into a JSON object. json_encode does not support it yet.

array example:

<?php
$series = array("name"=>"N51",
                "data"=>array(1024,
                              array("y"=>2048,
                                    "events"=>array("mouseOver"=>'function(){$reporting.html(\'description of value\');}')
                                   ),
                              4096)
               );
json_encode($series);
?>

output:

{"name":"N51","data":[1024,{"y":2048,"events":{"mouseOver":"function(){$reporting.html('description of value');}"}},4096]}

<?php json_encode_jsfunc($series); ?>
output:

{"name":"N51","data":[1024,{"y":2048,"events":{"mouseOver":function(){$reporting.html('description of value');}}},4096]}

The difference is quotes around function, there should not be quotes.

<?php
function json_encode_jsfunc($input=array(), $funcs=array(), $level=0)
 {
  foreach($input as $key=>$value)
         {
          if (is_array($value))
             {
              $ret = json_encode_jsfunc($value, $funcs, 1);
              $input[$key]=$ret[0];
              $funcs=$ret[1];
             }
          else
             {
              if (substr($value,0,10)=='function()')
                 {
                  $func_key="#".uniqid()."#";
                  $funcs[$func_key]=$value;
                  $input[$key]=$func_key;
                 }
             }
         }
  if ($level==1)
     {
      return array($input, $funcs);
     }
  else
     {
      $input_json = json_encode($input);
      foreach($funcs as $key=>$value)
             {
              $input_json = str_replace('"'.$key.'"', $value, $input_json);
             }
      return $input_json;
     }
 }
?>

anonymous at gmail dot com (12-Sep-2011 01:53)

Since PHP5.3 does not yet have JSON_UNESCAPED_UNICODE I had to find a way of leaving the unicode characters un-escaped in the json:
<?php
        array_walk_recursive($array, function(&$item, $key) {
            if(is_string($item)) {
                $item = htmlentities($item);
            }
        });
        $json = json_encode($array);
        $rson = html_entity_decode($rson);
?>

grkworld1 at yahoo dot co dot in (07-Sep-2011 10:45)

copy the php tagged code in a page
this is use full for multy dimention array

<?php

function arr_2_str($arr,$counter=1,$str="")
{
    foreach( $arr as $key=>$value)
    {
        if(is_array($value))
        {
            $str.= $key."=$counter>".arr_2_str($value,($counter+1))."=".$counter.">~Y~|".$counter."|";
        }
        else
        {
            $str.=$key."=$counter>".$value."|$counter|";
        }
    }
    return rtrim($str,"|$counter|");
}

function str_2_arr($str,$counter=1,$arr=array(),$temparr=array())
{
    $temparr=explode("|$counter|",$str);
   
    foreach( $temparr as $key=>$value)
    {
        $t1=explode("=$counter>",$value);
        $kk=$t1[0];
        $vv=$t1[1];
        if ($t1[2]=="~Y~")
        {
            $arr[$kk]=str_2_arr($vv,($counter+1));
        }
        else
        {
            $arr[$kk]=$vv;
        }
       
    }
    return $arr;
}

$arr=array();

$arr[1]="a";
$arr[2][1]="b";
$arr[2][2]="c";
$arr[2][3][1]="d";
$arr[2][3][2][1]="e1";
$arr[2][3][2][2]="e2";
$arr[2][3][3]="f";
print "<pre>";

print_r($arr);

print "<br><br><br>";

print $ssttrr=arr_2_str($arr);

print "<br><br><br>";

print_r(str_2_arr($ssttrr));

/*print "<br><br><br>";
print "use of json";
print "<br><br><br>";
print $sstr=json_encode($arr);
print "<br><br><br>";
print_r(json_decode($sstr));*/

print "</pre>";

?>

Tibor Halter (14-Aug-2011 01:21)

json_encode($binary) problem: it results in an empty string "" without error.

You will see this happening when encoding binary images, for example.

Use utf8_encode first.

<?php

    $data = 'éáíú?óü????';
    $json = json_encode( utf8_encode($data) );

    // [..]

    $data = utf8_decode( json_decode($json) );

?>

Rijk van Wel (07-Jul-2011 10:18)

The JSON_NUMERIC_CHECK flag introduced in 5.3.0 comes in very handy when handling numbers encapsulated in a string (database results and post requests are always encoded as string types, for example). Sending over variables from a database result directly (as string) would cause the json_encode() function to quote them, which in turn would make the Javascript store them as strings. As Javascript isn't loosely typed, some libraries could break on this, when attempting to use one of those variables as row id in a data store for instance. Using the aforementioned flag can prevent this from happening.

<?php
$arr = array( 'row_id' => '1', 'name' => 'George' ); // fictional db result
echo json_encode( $arr, JSON_NUMERIC_CHECK ); // {"row_id":1,"name":"George"}
?>

Mr Swordsteel (05-Jun-2011 03:38)

So i like to use ISO-8859-1 and a lot of ?????? and not that much for UTF-8 but i need some json stuff so this is what I'm trying to use this lite thing i made...

<?php
function my_json_encode($in) {
  $_escape = function ($str) {
    return addcslashes($str, "\v\t\n\r\f\"\\/");
  };
  $out = "";
  if (is_object($in)) {
    $class_vars = get_object_vars(($in));
    $arr = array();
    foreach ($class_vars as $key => $val) {
      $arr[$key] = "\"{$_escape($key)}\":\"{$val}\"";
    }
    $val = implode(',', $arr);
    $out .= "{{$val}}";
  }elseif (is_array($in)) {
    $obj = false;
    $arr = array();
    foreach($in AS $key => $val) {
      if(!is_numeric($key)) {
        $obj = true;
      }
      $arr[$key] = my_json_encode($val);
    }
    if($obj) {
      foreach($arr AS $key => $val) {
        $arr[$key] = "\"{$_escape($key)}\":{$val}";
      }
      $val = implode(',', $arr);
      $out .= "{{$val}}";
    }else {
      $val = implode(',', $arr);
      $out .= "[{$val}]";
    }
  }elseif (is_bool($in)) {
    $out .= $in ? 'true' : 'false';
  }elseif (is_null($in)) {
    $out .= 'null';
  }elseif (is_string($in)) {
    $out .= "\"{$_escape($in)}\"";
  }else {
    $out .= $in;
  }
  return "{$out}";
}
?>

have fun make money off it or what you like with you code... this is for everyone...

Joe (06-May-2011 07:24)

Just FYI, check out these other registered long constants from the PHP source code for json_d/ecode:

JSON_PRETTY_PRINT
JSON_UNESCAPED_SLASHES
JSON_NUMERIC_CHECK

I certainly look forward to these being fully included, especially the pretty print option for proof reading of javascript config props sent to things like Highcharts.

pvl dot kolensikov at gmail dot com (28-Mar-2011 04:35)

As json_encode() is recursive, you can use it to serialize whole structure of objects.

<?php
class A {
    public $a = 1;
    public $b = 2;
    public $collection = array();

    function  __construct(){
        for ( $i=3; $i-->0;){
            array_push($this->collection, new B);
        }
    }
}

class B {
    public $a = 1;
    public $b = 2;
}

echo json_encode(new A);
?>

Will give:

{
    "a":1,
    "b":2,
    "collection":[{
        "a":1,
        "b":2
    },{
        "a":1,
        "b":2
    },{
        "a":1,
        "b":2
    }]
}

Mathias Leppich (25-Feb-2011 06:29)

If you need a json_encode / json_decode which is array/object/assoc-array you might want to use: http://gist.github.com/820694

<?php
$dataIn = (object)array(
    "assoc" => array("cow"=>"moo"),
    "object" => (object)array("cat"=>"miao"),
);
/*
== IN
object(stdClass)#2 (2) {
  ["assoc"]=>
  array(1) {
    ["cow"]=>
    string(3) "moo"
  }
  ["object"]=>
  object(stdClass)#1 (1) {
    ["cat"]=>
    string(4) "miao"
  }
}

== JSON
{"assoc":{"_PHP_ASSOC":{"cow":"moo"}},"object":{"cat":"miao"}}

== OUT
object(stdClass)#4 (2) {
  ["assoc"]=>
  array(1) {
    ["cow"]=>
    string(3) "moo"
  }
  ["object"]=>
  object(stdClass)#7 (1) {
    ["cat"]=>
    string(4) "miao"
  }
}
*/
?>

Joao Neto (16-Feb-2011 12:36)

To solve the "problem" with encoded UTF8 chars, is easy:

for example:

<?php
$arr = array( 'áéíóú??', 'áááééé?r??' );

echo json_encode( $arr );

foreach ($arr as &$a) {
  $a = ascii_to_entities( $a );
}

echo json_encode( $arr );

function ascii_to_entities($str)
    {
       $count    = 1;
       $out    = '';
       $temp    = array();
   
       for ($i = 0, $s = strlen($str); $i < $s; $i++)
       {
           $ordinal = ord($str[$i]);
   
           if ($ordinal < 128)
           {
                if (count($temp) == 1)
                {
                    $out  .= '&#'.array_shift($temp).';';
                    $count = 1;
                }
           
                $out .= $str[$i];
           }
           else
           {
               if (count($temp) == 0)
               {
                   $count = ($ordinal < 224) ? 2 : 3;
               }
       
               $temp[] = $ordinal;
       
               if (count($temp) == $count)
               {
                   $number = ($count == 3) ? (($temp['0'] % 16) * 4096) +
(($temp['1'] % 64) * 64) +
($temp['2'] % 64) : (($temp['0'] % 32) * 64) +
($temp['1'] % 64);

                   $out .= '&#'.$number.';';
                   $count = 1;
                   $temp = array();
               }
           }
       }

       return $out;
    }
?>

RESULT:

["\u00e1\u00e9\u00ed\u00f3\u00fa\u00e7\u00e3",
"\u00e1\u00e1\u00e1\u00e9\u00e9\u00e9\u00b4r\u0155\u0155"]

Array ( [0] => áéíóú?? [1] => áááééé?r?? )

["áéíóú??","áááééé?r??"]

Array ( [0] => áéíóú?? [1] => áááééé?r?? )

vakondweb at gmail dot com (01-Feb-2011 09:01)

json_encode() only works with UTF-8 charset.

In case if you work with other charset, use this very simple solution instead of json_encode:

<?php
//$return_arr = the array of data to json encode
//$out = the output of the function
//don't forget to escape the data before use it!

$out = '["' . implode('","', $return_arr) . '"]';
?>

bohwaz (26-Jan-2011 10:00)

This is intended to be a simple readable json encode function for PHP 5.3+ (and licensed under GNU/AGPLv3 or GPLv3 like you prefer):

<?php

function json_readable_encode($in, $indent = 0, $from_array = false)
{
    $_myself = __FUNCTION__;
    $_escape = function ($str)
    {
        return preg_replace("!([\b\t\n\r\f\"\\'])!", "\\\\\\1", $str);
    };

    $out = '';

    foreach ($in as $key=>$value)
    {
        $out .= str_repeat("\t", $indent + 1);
        $out .= "\"".$_escape((string)$key)."\": ";

        if (is_object($value) || is_array($value))
        {
            $out .= "\n";
            $out .= $_myself($value, $indent + 1);
        }
        elseif (is_bool($value))
        {
            $out .= $value ? 'true' : 'false';
        }
        elseif (is_null($value))
        {
            $out .= 'null';
        }
        elseif (is_string($value))
        {
            $out .= "\"" . $_escape($value) ."\"";
        }
        else
        {
            $out .= $value;
        }

        $out .= ",\n";
    }

    if (!empty($out))
    {
        $out = substr($out, 0, -2);
    }

    $out = str_repeat("\t", $indent) . "{\n" . $out;
    $out .= "\n" . str_repeat("\t", $indent) . "}";

    return $out;
}

?>

dan at elearnapp dot com (13-Jan-2011 08:01)

If you need to force an object (ex: empty array) you can also do:

         <?php json_encode( (object)$arr ); ?>

which acts the same as

         <?php json_encode($arr, JSON_FORCE_OBJECT); ?>

marc at leftek dot com (23-Dec-2010 06:08)

Anybody having empty arrays and needing the JSON_FORCE_OBJECT option but not using 5.3 yet, you can substitute assigning an empty object:

<?php
    if (empty($array)) $array = (object) null;
    $return = json_encode($array);
?>

rdheijer at reestyle dot net (21-Dec-2010 10:11)

You may run into trouble when you need to call functions. In my case I had to fire a function based on a button pressed in the flexigrid javascript component.

My solution in the project was:

<?php

$jsonify = array('onpress'=>'functionName');

// The part between braces in the regex is somewhat rough
// but it will do the job. Afterall, you don't want this to be
// used by a visitor :)
$regex = '/"onpress":"([\w\-\.]+)"/i';
$replace = '"onpress":$1';
$jsonified = preg_replace($regex, $replace, json_encode($jsonify));

?>

But you can extend this for your own needs. By altering the regex and replace vars:

<?php

$replace = '"$1":$2';
$regex = '/"(onpress|onclick|onmouseover|onmouseout)":"([\w_\-\.]+)"/i';

?>

Unfortunately you have to specify each call reference, but it does give you full control over what to and what not to.

Andre M (06-Dec-2010 12:23)

Regarding encoding issues, if you make sure the PHP files containing your strings are encoded in UTF-8, you shouldn't need to call utf8_encode.

spam dot here dot pls at hotmail dot com (17-Nov-2010 08:42)

Another way for pre-5.2.0 PHP users is using rawurlencode() in PHP to encode a string and decodeURIComponent() in javascript to decode it. I have written following class to handle PHP arrays and convert them to javascript format. It uses object notation for associative arrays and arrays for the other. Nesting is supported. True, false, integers, floats and null values are presented in respective javascript syntax.

Use: convert an array in PHP using this class, load it into the browser using ajax and then decode the strings in the resulting object using javascript function decodeData (below).

All of the example results have passed json validator so it shoud be allright. Feel free to use this.

PHP CLASS - encoding arrays
=======

<?php

class custom_json {

    /**
     * Convert array to javascript object/array
     * @param array $array the array
     * @return string
     */
    public static function encode($array)
    {

        // determine type
        if(is_numeric(key($array))) {

            // indexed (list)
            $output = '[';
            for($i = 0, $last = (sizeof($array) - 1); isset($array[$i]); ++$i) {
                if(is_array($array[$i])) $output .= self::encode($array[$i]);
                else  $output .= self::_val($array[$i]);
                if($i !== $last) $output .= ',';
            }
            $output .= ']';

        } else {

            // associative (object)
            $output = '{';
            $last = sizeof($array) - 1;
            $i = 0;
            foreach($array as $key => $value) {
                $output .= '"'.$key.'":';
                if(is_array($value)) $output .= self::encode($value);
                else  $output .= self::_val($value);
                if($i !== $last) $output .= ',';
                ++$i;
            }
            $output .= '}';

        }

        // return
        return $output;

    }

    /**
     * [INTERNAL] Format value
     * @param mixed $val the value
     * @return string
     */
    private static function _val($val)
    {
        if(is_string($val)) return '"'.rawurlencode($val).'"';
        elseif(is_int($val)) return sprintf('%d', $val);
        elseif(is_float($val)) return sprintf('%F', $val);
        elseif(is_bool($val)) return ($val ? 'true' : 'false');
        else  return 'null';
    }

}

// prints ["apple","banana","blueberry"]
echo custom_json::encode(array('apple', 'banana', 'blueberry'));

// prints {"name":"orange","type":"fruit"}
echo custom_json::encode(array('name' => 'orange', 'type' => 'fruit'));

// prints: ** try it yourself, cannot post long lines here **
$big_test = array(
    array(
        'name' => array('John', 'Smith'),
        'age' => 27,
        'sex' => 0,
        'height' => 180.53,
        'is_human' => true,
        'string' => 'Hello',
    ),
    array(
        'name' => array('Green', 'Alien'),
        'age' => 642,
        'sex' => null,
        'height' => 92.21,
        'is_human' => false,
        'string' => 'こんにちは！', // test utf8 here
    )
);

echo custom_json::encode($big_test);

?>

JAVASCRIPT FUNCTION - decode rawurlencoded() strings
==================
function decodeData(data) {
        for(var item in data) {
            var type = typeof data[item];
            if(type === 'object') decodeData(data[item]);
            else if(type === 'string') data[item] = decodeURIComponent(data[item]);
        }
    }

boukeversteegh at gmail dot com (10-Nov-2010 02:02)

For users of php 5.1.6 or lower, a native json_encode function. This version handles objects, and makes proper distinction between [lists] and {associative arrays}, mixed arrays work as well. It can handle newlines and quotes in both keys and data.

This function will convert non-ascii symbols to "\uXXXX" format as does json_encode.

Besides that, it outputs exactly the same string as json_encode. Including UTF-8 encoded 2-, 3- and 4-byte characters. It is a bit faster than PEAR/JSON::encode, but still slow compared to php 5.3's json_encode. It encodes any variable type exactly as the original.

Relative speeds:
PHP json_encode: 1x
__json_encode: 31x
PEAR/JSON: 46x

NOTE: I assume the input will be valid UTF-8. I don't know what happens if your data contains illegal Unicode sequences. I tried to make the code fast and compact.

<?php
function __json_encode( $data ) {           
    if( is_array($data) || is_object($data) ) {
        $islist = is_array($data) && ( empty($data) || array_keys($data) === range(0,count($data)-1) );
       
        if( $islist ) {
            $json = '[' . implode(',', array_map('__json_encode', $data) ) . ']';
        } else {
            $items = Array();
            foreach( $data as $key => $value ) {
                $items[] = __json_encode("$key") . ':' . __json_encode($value);
            }
            $json = '{' . implode(',', $items) . '}';
        }
    } elseif( is_string($data) ) {
        # Escape non-printable or Non-ASCII characters.
        # I also put the \\ character first, as suggested in comments on the 'addclashes' page.
        $string = '"' . addcslashes($data, "\\\"\n\r\t/" . chr(8) . chr(12)) . '"';
        $json    = '';
        $len    = strlen($string);
        # Convert UTF-8 to Hexadecimal Codepoints.
        for( $i = 0; $i < $len; $i++ ) {
           
            $char = $string[$i];
            $c1 = ord($char);
           
            # Single byte;
            if( $c1 <128 ) {
                $json .= ($c1 > 31) ? $char : sprintf("\\u%04x", $c1);
                continue;
            }
           
            # Double byte
            $c2 = ord($string[++$i]);
            if ( ($c1 & 32) === 0 ) {
                $json .= sprintf("\\u%04x", ($c1 - 192) * 64 + $c2 - 128);
                continue;
            }
           
            # Triple
            $c3 = ord($string[++$i]);
            if( ($c1 & 16) === 0 ) {
                $json .= sprintf("\\u%04x", (($c1 - 224) <<12) + (($c2 - 128) << 6) + ($c3 - 128));
                continue;
            }
               
            # Quadruple
            $c4 = ord($string[++$i]);
            if( ($c1 & 8 ) === 0 ) {
                $u = (($c1 & 15) << 2) + (($c2>>4) & 3) - 1;
           
                $w1 = (54<<10) + ($u<<6) + (($c2 & 15) << 2) + (($c3>>4) & 3);
                $w2 = (55<<10) + (($c3 & 15)<<6) + ($c4-128);
                $json .= sprintf("\\u%04x\\u%04x", $w1, $w2);
            }
        }
    } else {
        # int, floats, bools, null
        $json = strtolower(var_export( $data, true ));
    }
    return $json;
}
?>

[EDIT BY danbrown AT php DOT net: Contains a bugfix by the original poster on 08-DEC-2010 with the following message: "I discovered a rather bad bug in my __json_encode function below. On versions prior to php 5.2.5, all 'f' characters are escaped to '\f'. This is because addcslashes in php < 5.2 doesn't understand \f as 'formfeed'."]

php at ianco dot co dot uk (30-Oct-2010 12:02)

Note that json_encode always escapes a solidus (forward slash, %x2F).
This may be a problem if you are encoding a URL.
It's been recognised and fixed in September 2010:
http://bugs.php.net/bug.php?id=49366
But escaping will still be the default behaviour.
A crude repair can be done with
str_replace('\\/', '/', $jsonEncoded)

josh [at] goals.com (23-Oct-2010 08:31)

For anyone wondering whether umbrae's JSON pretty-printer will output invalid JSON (I did), I ran some tests taking my valid JSON and replacing string values with each of the possible edge cases: [, {, ,, :, ", }, and ]. I then ran the output through JSONLint just to verify.

So far as I can tell, nothing breaks in these situations, and everything pretty-prints as expected.

That said, quotes " will produce invalid JSON, but this is only an issue if you're using json_encode() and just expect PHP to magically escape your quotes. You need to do the escaping yourself.

migprj at gmail dot com (19-Oct-2010 03:46)

Because json_encode() only deals with utf8, it is often necessary to convert all the string values inside an array to utf8. I've created these two functions:   

<?php
function utf8_encode_all($dat) // -- It returns $dat encoded to UTF8
{
  if (is_string($dat)) return utf8_encode($dat);
  if (!is_array($dat)) return $dat;
  $ret = array();
  foreach($dat as $i=>$d) $ret[$i] = utf8_encode_all($d);
  return $ret;
}
/* ....... */

function utf8_decode_all($dat) // -- It returns $dat decoded from UTF8
{
  if (is_string($dat)) return utf8_decode($dat);
  if (!is_array($dat)) return $dat;
  $ret = array();
  foreach($dat as $i=>$d) $ret[$i] = utf8_decode_all($d);
  return $ret;
}
/* ....... */
?>

tomas at matfyz dot cz (05-Oct-2010 03:43)

As json_encode() won't work with character sets other than UTF-8, this expression allows to encode strings for JSON regardless of the character set:

<?php
str_replace("\0", "\\u0000", addcslashes($string, "\t\r\n\"\\"));
?>

You need to replace the nul character manually as addcslashes() won't do it right way. But BEWARE, this is only solution for common strings, other "unusual wild characters" like ESC, \b, \a etc. are not handled.

matt dot parlane at gmail dot com (05-Oct-2010 08:05)

To save some space, at the risk of it being illegal JSON, strictly speaking:

<?php
$json = preg_replace('/"([a-zA-Z]+[a-zA-Z0-9]*)":/', '$1:', json_encode($whatever));
?>

Dave - s10sys.com (09-Sep-2010 04:46)

This may help others who are seeing null strings returned by json_encode().

This function will encode all array values to utf8 so they are safe for json_encode();

usage:

<?php
json_encode(utf8json($dataArray));

function utf8json($inArray) {

    static $depth = 0;

    /* our return object */
    $newArray = array();

    /* safety recursion limit */
    $depth ++;
    if($depth >= '30') {
        return false;
    }

    /* step through inArray */
    foreach($inArray as $key=>$val) {
        if(is_array($val)) {
            /* recurse on array elements */
            $newArray[$key] = utf8json($val);
        } else {
            /* encode string values */
            $newArray[$key] = utf8_encode($val);
        }
    }

    /* return utf8 encoded array */
    return $newArray;
}
?>

[NOTE BY danbrown AT php DOT net: Includes a bugfix by (robbiz233 AT hotmail DOT com) on 18-SEP-2010, to replace:
    $newArray[$key] = utf8json($inArray);
with:
    $newArray[$key] = utf8json($val);"
in the given function.]

nicolas dot baptiste at gmail dot com (18-Aug-2010 04:49)

Beware of index arrays :

<?php
echo json_encode(array("test","test","test"));
echo json_encode(array(0=>"test",3=>"test",7=>"test"));
?>

Will give :

["test","test","test"]
{"0":"test","3":"test","7":"test"}

arrays are returned only if you don't define index.

gansbrest (06-Aug-2010 08:42)

If you have problems with quotes when encoding numeric data retrieved from the database, you can just cast that value to integer and there will be no quotes:

<?php
$testArr['key'] = '1';
print json_encode($testArr);
?>

===> {"key":"1"}

<?php
$testArr['key'] = (int)'1';
print json_encode($testArr);
?>

===> {"key":1}

Don't forget that you have to deal with numbers, otherwise your string will be converted to 0.

Arne Bech (20-Jul-2010 08:00)

To battle the quoting of numbers when encoding data retrieved from mysql you could do a simple preg_replace() to remove the quotes on numbers.

This has worked for me:
<?php
$json = json_encode($dataFromMysql);
$json = preg_replace('/"(-?\d+\.?\d*)"/', '$1', $json);
?>

mic dot sumner at gmail dot com (02-Jul-2010 02:39)

Hey everyone,

In my application, I had objects that modeled database rows with a few one to many relationships, so one object may have an array of other objects.

I wanted to make the object properties private and use getters and setters, but I needed them to be serializable to json without losing the private variables. (I wanted to promote good coding practices but I needed the properties on the client side.) Because of this, I needed to encode not only the normal private properties but also properties that were arrays of other model objects. I looked for awhile with no luck, so I coded my own:

You can place these methods in each of your classes, or put them in a base class, as I've done. (But note that for this to work, the children classes must declare their properties as protected so the parent class has access)

<?php
abstract class Model {
  
   public function toArray() {
        return $this->processArray(get_object_vars($this));
    }
   
    private function processArray($array) {
        foreach($array as $key => $value) {
            if (is_object($value)) {
                $array[$key] = $value->toArray();
            }
            if (is_array($value)) {
                $array[$key] = $this->processArray($value);
            }
        }
        // If the property isn't an object or array, leave it untouched
        return $array;
    }
   
    public function __toString() {
        return json_encode($this->toArray());
    }
  
}
?>

Externally, you can just call

<?php
    echo $theObject;
    //or
    echo json_encode($theObject->toArray());
?>

And you'll get the json for that object. Hope this helps someone!

ryan at ryanparman dot com (27-Mar-2010 09:36)

I came across the "bug" where running json_encode() over a SimpleXML object was ignoring the CDATA. I ran across http://bugs.php.net/42001 and http://bugs.php.net/41976, and while I agree with the poster that the documentation should clarify gotchas like this, I was able to figure out how to workaround it.

You need to convert the SimpleXML object back into an XML string, then re-import it back into SimpleXML using the LIBXML_NOCDATA option. Once you do this, then you can use json_encode() and still get back the CDATA.

<?php
// Pretend we already have a complex SimpleXML object stored in $xml
$json = json_encode(new SimpleXMLElement($xml->asXML(), LIBXML_NOCDATA));
?>

5hunter5 at mail dot ru (17-Feb-2010 11:03)

If I want to encode object whith all it's private and protected properties, then I implements that methods in my object:

<?php
public function encodeJSON()
{
    foreach ($this as $key => $value)
    {
        $json->$key = $value;
    }
    return json_encode($json);
}
public function decodeJSON($json_str)
{
    $json = json_decode($json_str, 1);
    foreach ($json as $key => $value)
    {
        $this->$key = $value;
    }
}
?>

Or you may extend your class from base class, wich is implements that methods.

Found that much more simple than regular expressions with PHP serialized objects...

olivier dot pons dot no dot spam at gmail dot com (22-Jan-2010 03:13)

Be careful about one thing:
With a string key Php will consider it's an object:

<?php
echo json_encode(array('id'=>'testtext'));
echo json_encode(array('testtext'));
?>

Will give:

{"id":"testtext"}
["testtext"]

Beware of the string keys!

garydavis at gmail dot com (14-Jan-2010 03:38)

If you are planning on using this function to serve a json file, it's important to note that the json generated by this function is not ready to be consumed by javascript until you wrap it in parens and add ";" to the end.

It took me a while to figure this out so I thought I'd save others the aggravation.

<?php
    header('Content-Type: text/javascript; charset=utf8');
    header('Access-Control-Allow-Origin: http://www.example.com/');
    header('Access-Control-Max-Age: 3628800');
    header('Access-Control-Allow-Methods: GET, POST, PUT, DELETE');
   
    $file='rss.xml';
    $arr = simplexml_load_file($file);//this creates an object from the xml file
    $json= '('.json_encode($arr).');'; //must wrap in parens and end with semicolon
    print_r($_GET['callback'].$json); //callback is prepended for json-p
?>

me at daniel dot ie (15-Nov-2009 04:45)

I had trouble putting the results of mysql_fetch_assoc() through json_encode: numbers being returned from the query were being quoted in the JSON output (i.e., they were being treated as strings). In order to fix this, it is necessary to explicitly cast each element of the array before json_encode() is called.

The following code uses metadata from a MySQL query result to do this casting.

<?php
    $mysql = mysql_connect('localhost', 'user', 'password');
    mysql_select_db('my_db');

    $query = 'select * from my_table';
    $res = mysql_query($query);

    // iterate over every row
    while ($row = mysql_fetch_assoc($res)) {
        // for every field in the result..
        for ($i=0; $i < mysql_num_fields($res); $i++) {
            $info = mysql_fetch_field($res, $i);
            $type = $info->type;

            // cast for real
            if ($type == 'real')
                $row[$info->name] = doubleval($row[$info->name]);
            // cast for int
            if ($type == 'int')
                $row[$info->name] = intval($row[$info->name]);
        }

        $rows[] = $row;
    }

    // JSON-ify all rows together as one big array
    echo json_encode($rows);
   
    mysql_close($mysql);
?>

rlz_ar at yahoo dot com (30-Oct-2009 04:35)

If you have problems with json_encode() on arrays, you can force json_encode() to encode as object, and then use json_decode() casting the result as array:

<?php

$myarray = Array('isa', 'dalawa', 'tatlo');

unset($myarray[1]);

$json_encoded_array = json_encode ( $myarray, JSON_FORCE_OBJECT );

// do whatever you want with your data
// then you can retrive the data doing:

$myarray = (array) json_decode ( $json_encoded_array );

?>

simoncpu was here (20-Oct-2009 10:18)

A note of caution: If you are wondering why json_encode() encodes your PHP array as a JSON object instead of a JSON array, you might want to double check your array keys because json_encode() assumes that you array is an object if your keys are not sequential.

e.g.:

<?php
$myarray = Array('isa', 'dalawa', 'tatlo');
var_dump($myarray);
/* output
array(3) {
  [0]=>
  string(3) "isa"
  [1]=>
  string(6) "dalawa"
  [2]=>
  string(5) "tatlo"
}
*/
?>

As you can see, the keys are sequential; $myarray will be correctly encoded as a JSON array.

<?php
$myarray = Array('isa', 'dalawa', 'tatlo');

unset($myarray[1]);
var_dump($myarray);
/* output
array(2) {
  [0]=>
  string(3) "isa"
  [2]=>
  string(5) "tatlo"
}
*/
?>

Unsetting an element will also remove the keys. json_encode() will now assume that this is an object, and will encode it as such.

SOLUTION: Use array_values() to re-index the array.

http://mike.eire.ca/ (10-Aug-2009 09:54)

Note that this function does not always produce legal JSON.

<?php
$json = json_encode('foo');
var_dump($json);
//string(5) ""foo""

$json = json_encode(23);
var_dump($json);
//string(2) "23"
?>

According to the JSON spec, only objects and arrays can be represented; the JSON_FORCE_OBJECT flag available since PHP 5.3 does not change this behaviour. If you're using this to produce JSON that will be exchanged with other systems, adjust your output accordingly.

<?php
$json = preg_replace('/^([^[{].*)$/', '[$1]', $json);
?>

The json_decode function accepts these JSON fragments without complaint.

damon1977 at gmail dot com (28-Jul-2009 08:41)

I wrote a function to make JSON strings more readable. It's very useful for debugging JSON output...

<?php
function jsonReadable($json, $html=FALSE) {
    $tabcount = 0;
    $result = '';
    $inquote = false;
    $ignorenext = false;
   
    if ($html) {
        $tab = "&nbsp;&nbsp;&nbsp;";
        $newline = "<br/>";
    } else {
        $tab = "\t";
        $newline = "\n";
    }
   
    for($i = 0; $i < strlen($json); $i++) {
        $char = $json[$i];
       
        if ($ignorenext) {
            $result .= $char;
            $ignorenext = false;
        } else {
            switch($char) {
                case '{':
                    $tabcount++;
                    $result .= $char . $newline . str_repeat($tab, $tabcount);
                    break;
                case '}':
                    $tabcount--;
                    $result = trim($result) . $newline . str_repeat($tab, $tabcount) . $char;
                    break;
                case ',':
                    $result .= $char . $newline . str_repeat($tab, $tabcount);
                    break;
                case '"':
                    $inquote = !$inquote;
                    $result .= $char;
                    break;
                case '\\':
                    if ($inquote) $ignorenext = true;
                    $result .= $char;
                    break;
                default:
                    $result .= $char;
            }
        }
    }
   
    return $result;
}
?>

Istratov Vadim (10-Jun-2009 07:54)

Be careful with floating values in some locales (e.g. russian) with comma (",") as decimal point. Code:

<?php
setlocale(LC_ALL, 'ru_RU.utf8');

$arr = array('element' => 12.34);
echo json_encode( $arr );
?>

Output will be:
--------------
{"element":12,34}
--------------

Which is NOT a valid JSON markup. You should convert floating point variable to strings or set locale to something like "LC_NUMERIC, 'en_US.utf8'" before using json_encode.

other at killermonk dot com (20-May-2009 10:55)

If you are trying to flatten a multi dimensional array, you can also just use serialize and unserialize. It just depends on what you are trying to do.

Sam Barnum (21-Apr-2009 07:01)

Note that if you try to encode an array containing non-utf values, you'll get null values in the resulting JSON string.  You can batch-encode all the elements of an array with the array_map function:
<?php
$encodedArray = array_map(utf8_encode, $rawArray);
?>

atrauzzi at gmail dot com (08-Apr-2009 08:39)

Here's an idea for people trying to figure out an alternative to implode() to flatten multi-dimensional arrays.

Use json_encode()!

I needed a way to create a hash from an array:

md5(json_encode($multiDimensionalArray)) does the trick!

Happy caching!

andyrusterholz at g-m-a-i-l dot c-o-m (27-Mar-2009 07:17)

For anyone who would like to encode arrays into JSON, but is using PHP 4, and doesn't want to wrangle PECL around, here is a function I wrote in PHP4 to convert nested arrays into JSON.

Note that, because javascript converts JSON data into either nested named objects OR vector arrays, it's quite difficult to represent mixed PHP arrays (arrays with both numerical and associative indexes) well in JSON. This function does something funky if you pass it a mixed array -- see the comments for details.

I don't make a claim that this function is by any means complete (for example, it doesn't handle objects) so if you have any improvements, go for it.

<?php

/**
 * Converts an associative array of arbitrary depth and dimension into JSON representation.
 *
 * NOTE: If you pass in a mixed associative and vector array, it will prefix each numerical
 * key with "key_". For example array("foo", "bar" => "baz") will be translated into
 * {'key_0': 'foo', 'bar': 'baz'} but array("foo", "bar") would be translated into [ 'foo', 'bar' ].
 *
 * @param $array The array to convert.
 * @return mixed The resulting JSON string, or false if the argument was not an array.
 * @author Andy Rusterholz
 */
function array_to_json( $array ){

    if( !is_array( $array ) ){
        return false;
    }

    $associative = count( array_diff( array_keys($array), array_keys( array_keys( $array )) ));
    if( $associative ){

        $construct = array();
        foreach( $array as $key => $value ){

            // We first copy each key/value pair into a staging array,
            // formatting each key and value properly as we go.

            // Format the key:
            if( is_numeric($key) ){
                $key = "key_$key";
            }
            $key = "'".addslashes($key)."'";

            // Format the value:
            if( is_array( $value )){
                $value = array_to_json( $value );
            } else if( !is_numeric( $value ) || is_string( $value ) ){
                $value = "'".addslashes($value)."'";
            }

            // Add to staging array:
            $construct[] = "$key: $value";
        }

        // Then we collapse the staging array into the JSON form:
        $result = "{ " . implode( ", ", $construct ) . " }";

    } else { // If the array is a vector (not associative):

        $construct = array();
        foreach( $array as $value ){

            // Format the value:
            if( is_array( $value )){
                $value = array_to_json( $value );
            } else if( !is_numeric( $value ) || is_string( $value ) ){
                $value = "'".addslashes($value)."'";
            }

            // Add to staging array:
            $construct[] = $value;
        }

        // Then we collapse the staging array into the JSON form:
        $result = "[ " . implode( ", ", $construct ) . " ]";
    }

    return $result;
}

?>

aangel at spam dot com (08-Feb-2009 01:50)

Here is a bit more on creating an iterator to get at those pesky private/protected variables:

<?php
   class Kit implements IteratorAggregate {

    public function __construct($var) {
        if (is_object($var)) {
            // if passed an object, we are cloning
           $this->kitID = $var->kitID;
           $this->kitName = $var->kitName;
           foreach ($var->productArray as $key => $value) {
               $this->productArray[$key] = (array)$value;
           }
        }
    }
   ...
    // Create an iterator because private/protected vars can't
    // be seen by json_encode().
    public function getIterator() {
        $iArray['kitID'] = $this->kitID;
        $iArray['kitName'] = $this->kitName;
        $iArray['productArray'] = (array)$this->productArray;
        return new ArrayIterator($iArray);
    }
}
?>

Calling something like  $t = json_encode($this->getIterator());  will give you almost what you want:
<?php
{"kitID":"Kit_Essentials-Books.txt",
"kitName":"Essential Books",
"productArray":{"0470043601":{"Category":"Food","ASIN":"0470043601"} } }
?>

Notice that the productArray is converted to an object ignoring the cast I put in front, which is not what I wanted. I haven't figured out how to make sure that encodes as an array.

Regardless, bringing that JSON back into an object using json_decode() will give you just a std object, and the only way I've found to get it into the proper object type is to use a constructor that instantiates the object the way it's supposed to be (see __construct($var) above). Like this:
<?php

        $newKit = new Kit(json_decode($t));
?>

Garrett (22-Oct-2008 07:17)

A note about json_encode automatically quoting numbers:

It appears that the json_encode function pays attention to the data type of the value. Let me explain what we came across:

We have found that when retrieving data from our database, there are occasions when numbers appear as strings to json_encode which results in double quotes around the values.

This can lead to problems within javascript functions expecting the values to be numeric.

This was discovered when were were retrieving fields from the database which contained serialized arrays. After unserializing them and sending them through the json_encode function the numeric values in the original array were now being treated as strings and showing up with double quotes around them.

The fix: Prior to encoding the array, send it to a function which checks for numeric types and casts accordingly. Encoding from then on worked as expected.

stboisvert at nowantspam dot gmail dot com (14-Oct-2008 08:27)

When Using Libraries such as Prototype you may find that once in a while when you return what you believe to be a empty array it will have a different behavior (vis a vis enumerables) than when you give it an associative array. To "fix" this, on your JS you may want to look for extended object properties to verify if it is an empty array or an ocject.

example:

<?php
if (transport.responseJSON['User'].length == undefined){
        var user = $H(transport.responseJSON['User']);
}else{
        var user = transport.responseJSON['User'];     
}
?>

Thanks goes out to :
jani@php.net

This is totally expected behaviour. Please read this:
http://www.json.org/

Note: array and assoc-array are different things. Latter being "object"
in json.

http://bugs.php.net/bug.php?id=45162

[RQuadling] See http://bugs.php.net/bug.php?id=47493. Fixed by using json_encode(array(), JSON_FORCE_OBJECT);

spam.goes.in.here AT gmail.com (09-Aug-2008 07:05)

For anyone who has run into the problem of private properties not being added, you can simply implement the IteratorAggregate interface with the getIterator() method. Add the properties you want to be included in the output into an array in the getIterator() method and return it.

umbrae at gmail dot com (10-Jan-2008 06:21)

Here's a quick function to pretty-print some JSON. Optimizations welcome, as this was a 10-minute dealie without efficiency in mind:

<?php
// Pretty print some JSON
function json_format($json)
{
    $tab = "  ";
    $new_json = "";
    $indent_level = 0;
    $in_string = false;

    $json_obj = json_decode($json);

    if($json_obj === false)
        return false;

    $json = json_encode($json_obj);
    $len = strlen($json);

    for($c = 0; $c < $len; $c++)
    {
        $char = $json[$c];
        switch($char)
        {
            case '{':
            case '[':
                if(!$in_string)
                {
                    $new_json .= $char . "\n" . str_repeat($tab, $indent_level+1);
                    $indent_level++;
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case '}':
            case ']':
                if(!$in_string)
                {
                    $indent_level--;
                    $new_json .= "\n" . str_repeat($tab, $indent_level) . $char;
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case ',':
                if(!$in_string)
                {
                    $new_json .= ",\n" . str_repeat($tab, $indent_level);
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case ':':
                if(!$in_string)
                {
                    $new_json .= ": ";
                }
                else
                {
                    $new_json .= $char;
                }
                break;
            case '"':
                if($c > 0 && $json[$c-1] != '\\')
                {
                    $in_string = !$in_string;
                }
            default:
                $new_json .= $char;
                break;                   
        }
    }

    return $new_json;
}
?>

jjoss (24-Oct-2007 08:07)

Another way to work with Russian characters. This procedure just handles Cyrillic characters without UTF conversion. Thanks to JsHttpRequest developers.

<?php
function php2js($a=false)
{
  if (is_null($a)) return 'null';
  if ($a === false) return 'false';
  if ($a === true) return 'true';
  if (is_scalar($a))
  {
    if (is_float($a))
    {
      // Always use "." for floats.
      $a = str_replace(",", ".", strval($a));
    }

    // All scalars are converted to strings to avoid indeterminism.
    // PHP's "1" and 1 are equal for all PHP operators, but
    // JS's "1" and 1 are not. So if we pass "1" or 1 from the PHP backend,
    // we should get the same result in the JS frontend (string).
    // Character replacements for JSON.
    static $jsonReplaces = array(array("\\", "/", "\n", "\t", "\r", "\b", "\f", '"'),
    array('\\\\', '\\/', '\\n', '\\t', '\\r', '\\b', '\\f', '\"'));
    return '"' . str_replace($jsonReplaces[0], $jsonReplaces[1], $a) . '"';
  }
  $isList = true;
  for ($i = 0, reset($a); $i < count($a); $i++, next($a))
  {
    if (key($a) !== $i)
    {
      $isList = false;
      break;
    }
  }
  $result = array();
  if ($isList)
  {
    foreach ($a as $v) $result[] = php2js($v);
    return '[ ' . join(', ', $result) . ' ]';
  }
  else
  {
    foreach ($a as $k => $v) $result[] = php2js($k).': '.php2js($v);
    return '{ ' . join(', ', $result) . ' }';
  }
}
?>

jfdsmit at gmail dot com (23-Oct-2007 03:31)

json_encode also won't handle objects that do not directly expose their internals but through the Iterator interface. These two function will take care of that:

<?php

/**
 * Convert an object into an associative array
 *
 * This function converts an object into an associative array by iterating
 * over its public properties. Because this function uses the foreach
 * construct, Iterators are respected. It also works on arrays of objects.
 *
 * @return array
 */
function object_to_array($var) {
    $result = array();
    $references = array();

    // loop over elements/properties
    foreach ($var as $key => $value) {
        // recursively convert objects
        if (is_object($value) || is_array($value)) {
            // but prevent cycles
            if (!in_array($value, $references)) {
                $result[$key] = object_to_array($value);
                $references[] = $value;
            }
        } else {
            // simple values are untouched
            $result[$key] = $value;
        }
    }
    return $result;
}

/**
 * Convert a value to JSON
 *
 * This function returns a JSON representation of $param. It uses json_encode
 * to accomplish this, but converts objects and arrays containing objects to
 * associative arrays first. This way, objects that do not expose (all) their
 * properties directly but only through an Iterator interface are also encoded
 * correctly.
 */
function json_encode2($param) {
    if (is_object($param) || is_array($param)) {
        $param = object_to_array($param);
    }
    return json_encode($param);
}

dennispopel(at)gmail.com (26-Aug-2007 06:43)

Obviously, this function has trouble encoding arrays with empty string keys (''). I have just noticed that (because I was using a function in PHP under PHP4). When I switched to PHP5's json_encode, I noticed that browsers could not correctly parse the encoded data. More investigation maybe needed for a bug report, but this quick note may save somebody several hours.

Also, it manifests on Linux in 5.2.1 (tested on two boxes), on my XP with PHP5.2.3 json_encode() works just great! However, both 5.2.1 and 5.2.3 phpinfo()s show that the json version is 1.2.1 so might be Linux issue

php at mikeboers dot com (05-Jul-2007 03:49)

Here is a way to convert an object to an array which will include all protected and private members before you send it to json_encode()

<?php

function objectArray( $object ) {

    if ( is_array( $object ))
        return $object ;
       
    if ( !is_object( $object ))
        return false ;
       
    $serial = serialize( $object ) ;
    $serial = preg_replace( '/O:\d+:".+?"/' ,'a' , $serial ) ;
    if( preg_match_all( '/s:\d+:"\\0.+?\\0(.+?)"/' , $serial, $ms, PREG_SET_ORDER )) {
        foreach( $ms as $m ) {
            $serial = str_replace( $m[0], 's:'. strlen( $m[1] ) . ':"'.$m[1] . '"', $serial ) ;
        }
    }
   
    return @unserialize( $serial ) ;

}

// TESTING

class A {
   
    public $a = 'public for a' ;
    protected $b = true ;
    private $c = 123 ;
   
}

class B {
   
    public $d = 'public for b' ;
    protected $e = false ;
    private $f = 456 ;
   
}

$a = new A() ;
$a -> d = new B() ;

echo '<pre>' ;
print_r( $a ) ;
print_r( objectArray( $a )) ;

?>

Cheers!

mike

Yi-Ren Chen at NCTU CSIE (02-May-2007 05:55)

I write a function "php_json_encode"
for early version of php which support "multibyte" but doesn't support "json_encode".
<?php
  function json_encode_string($in_str)
  {
    mb_internal_encoding("UTF-8");
    $convmap = array(0x80, 0xFFFF, 0, 0xFFFF);
    $str = "";
    for($i=mb_strlen($in_str)-1; $i>=0; $i--)
    {
      $mb_char = mb_substr($in_str, $i, 1);
      if(mb_ereg("&#(\\d+);", mb_encode_numericentity($mb_char, $convmap, "UTF-8"), $match))
      {
        $str = sprintf("\\u%04x", $match[1]) . $str;
      }
      else
      {
        $str = $mb_char . $str;
      }
    }
    return $str;
  }
  function php_json_encode($arr)
  {
    $json_str = "";
    if(is_array($arr))
    {
      $pure_array = true;
      $array_length = count($arr);
      for($i=0;$i<$array_length;$i++)
      {
        if(! isset($arr[$i]))
        {
          $pure_array = false;
          break;
        }
      }
      if($pure_array)
      {
        $json_str ="[";
        $temp = array();
        for($i=0;$i<$array_length;$i++)       
        {
          $temp[] = sprintf("%s", php_json_encode($arr[$i]));
        }
        $json_str .= implode(",",$temp);
        $json_str .="]";
      }
      else
      {
        $json_str ="{";
        $temp = array();
        foreach($arr as $key => $value)
        {
          $temp[] = sprintf("\"%s\":%s", $key, php_json_encode($value));
        }
        $json_str .= implode(",",$temp);
        $json_str .="}";
      }
    }
    else
    {
      if(is_string($arr))
      {
        $json_str = "\"". json_encode_string($arr) . "\"";
      }
      else if(is_numeric($arr))
      {
        $json_str = $arr;
      }
      else
      {
        $json_str = "\"". json_encode_string($arr) . "\"";
      }
    }
    return $json_str;
  }

giunta dot gaetano at sea-aeroportimilano dot it (04-Sep-2006 04:11)

Take care that json_encode() expects strings to be encoded to be in UTF8 format, while by default PHP strings are ISO-8859-1 encoded.
This means that

json_encode(array('àü'));

will produce a json representation of an empty string, while

json_encode(array(utf8_encode('àü')));

will work.
The same applies to decoding, too, of course...