json_encode

(no version information, might be only in CVS)

json_encode -- Returns the JSON representation of a value

Description

string json_encode ( mixed value )

Returns a string containing the JSON representation of value.

Parameters

value: The value being encoded. Can be any type except a resource.

Return Values

Returns a JSON encoded string on success.

Examples

Example 1. A json_encode() example


<?php

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



echo json_encode($arr);

?>

The above example will output:

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


One of the purpose of JSON is to be easy for humans to read and write. But the output of json_encode() doen't indent very nicely... a "flat" string !



This function might help to have a nice identation :)

<?php

echo indentJson(json_encode($anArray));



function indentJson($str){

   $strOut = '';

   $identPos = 0;

   for($loop = 0;$loop<= strlen($str) ;$loop++){

       $_char = substr($str,$loop,1);

       //part 1

       if($_char == '}' || $_char == ']'){

           $strOut .= chr(13);

           $identPos --;

           for($ident = 0;$ident < $identPos;$ident++){

               $strOut .= chr(9);

           }

       }

       //part 2

       $strOut .= $_char;

       //part 3

       if($_char == ',' || $_char == '{' || $_char == '['){

           $strOut .= chr(13);

           if($_char == '{' || $_char == '[')

               $identPos ++;

           for($ident = 0;$ident < $identPos;$ident++){

               $strOut .= chr(9);

           }

       }

   }

   return $strOut;

?>

Andrea Giammarchi
19-Nov-2006 02:48


// ... and this is performance/memory optimized version :)

function json_real_encode($obj){

    $f = $r = array();

    foreach(array_merge(range(0, 7), array(11), range(14, 31)) as $v) {

        $f[] = chr($v);

        $r[] = "\\u00".sprintf("%02x", $v);

    }

    return str_replace($f, $r, json_encode($obj));

}

Andrea Giammarchi
18-Nov-2006 01:24


// fixes unconverted chars in range 00-1f

function json_real_encode($obj){

    $range = array_merge(range(0, 7), array(11), range(14, 31));

    return str_replace(

        array_map(create_function('&$i', 'return chr($i);'), $range),

        array_map(create_function('&$i', 'return $i ? "\\u00".sprintf("%02x", $i) : "\\u0000";'), $range),

        json_encode($obj)

    );

}

giunta dot gaetano at sea-aeroportimilano dot it
04-Sep-2006 10:11


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...

RQuadling at GMail dot com
01-Sep-2006 07:40


In trying to get an array which contains &, " ' in it into a JS select took me a little while.



My solution is a combination of htmlentites() and addslashes(), just like any other sort of data output.



The example code takes an array and creates a JS object (as the PHP variable is an associative array).



I also use both single and double quotes in the eval statement to prove resilience.



See http://rquadling.php1h.com/ for this and other usefull info.



<?php

// Define array with missing indexes.

$a_List = array

    (

    0 => 'Examine Locks',

    1 => 'Get Grade',

    2 => 'Get Manufacturer',

    3 => "Get Manufacturer's Pattern", // unescaped '

    6 => 'Get Mould Number',

    7 => 'Validate A&R', // & will become &amp;

    'Quote' => '"The answer is : 42".', // " will becode &quot;

    'Last' => 'Quit Process',

    );



// Make sure any HTML Entities are not sent unescaped.

foreach($a_List as $m_Key => $m_Value)

    {

    $a_List[$m_Key] = htmlentities($m_Value);

    }



// JSON Encode the list

$s_JSON_Encoded = addslashes(json_encode($a_List));



// Get the list into simple variable for printing.

$s_List = var_export($a_List, True);



// Output the results along with some JS to show what was received.

echo <<< END_TEXT

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">

<head>

<title>JSON test</title>

</head>

<body>

<div>Original Data : <pre>$s_List</pre></div>

<div>JSON Encoded : <pre>$s_JSON_Encoded</pre></div>

<div>JSON Decoded : <pre><script language="JavaScript" type="text/javascript">

var obj_dq = eval("($s_JSON_Encoded)");

var obj_sq = eval('($s_JSON_Encoded)');

var s_dq = '';

var s_sq = '';

for(var s_label in obj_dq)

    {

    s_dq = s_dq + '\\n' + s_label + ' => ' + obj_dq[s_label] + ',';

    }

for(var s_label in obj_sq)

    {

    s_sq = s_sq + '\\n' + s_label + ' => ' + obj_sq[s_label] + ',';

    }

document.writeln(s_dq + '\\n' + s_sq);

</script></pre></div>

</body>

</html>

END_TEXT;

?>

RQuadling at GMail dot com
01-Sep-2006 06:54


Contrary to the manual as at 2006/09/01, the only types that can be json_encode'd are arrays and objects.



See http://bugs.php.net/bug.php?id=38680 for a script to show things working (or not).

add a note

kadm5

json_decode

Last updated: Wed, 03 Jun 2009

json_encode

Description

Parameters

Return Values

Examples

See Also