Format JSON with PHP

4 Comments Published March 11th, 2008 in Javascript, PHP, Programming, Web

/**
 * Indents a flat JSON string to make it more human-readable
 *
 * @param string $json The original JSON string to process
 * @return string Indented version of the original JSON string
 */
public static function indent($json) {
 
    $result    = '';
    $pos       = 0;
    $strLen    = strlen($json);
    $indentStr = '  ';
    $newLine   = "\n";
 
    for($i = 0; $i <= $strLen; $i++) {
        
        // Grab the next character in the string
        $char = substr($json, $i, 1);
        
        // If this character is the end of an element, 
        // output a new line and indent the next line
        if($char == '}' || $char == ']') {
            $result .= $newLine;
            $pos --;
            for ($j=0; $j<$pos; $j++) {
                $result .= $indentStr;
            }
        }
        
        // Add the character to the result string
        $result .= $char;
 
        // If the last character was the beginning of an element, 
        // output a new line and indent the next line
        if ($char == ',' || $char == '{' || $char == '[') {
            $result .= $newLine;
            if ($char == '{' || $char == '[') {
                $pos ++;
            }
            for ($j = 0; $j < $pos; $j++) {
                $result .= $indentStr;
            }
        }
    }
 
    return $result;
}

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4 Responses to “Format JSON with PHP”

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1 Resat 2008/12/29 11:09

Thank you man. This function very simple & usefull. Now i can easely read server json responses.
2 dave 2008/12/29 17:32

No problem, glad you found it useful!
3 Jim Higson 2009/05/02 01:06

Hi, I found this in Google and made a Smarty (see smarty.net) plugin out of it in about twenty seconds:

Thanks.

<?php

/* Taken from http://recurser.com/articles/2008/03/11/format-json-with-php/ */

/**
* Indents a flat JSON string to make it more human-readable
*
* param string $json The original JSON string to process *return string Indented version of the original JSON string
*/
function smarty_modifier_formatjson($json) {

$result = ‘’;
$pos = 0;
$strLen = strlen($json);
$indentStr = ‘ ‘;
$newLine = “\n”;

for($i = 0; $i <= $strLen; $i ) {

// Grab the next character in the string
$char = substr($json, $i, 1);

// If this character is the end of an element,
// output a new line and indent the next line
if($char ‘}’ || $char ‘]’) {
$result .= $newLine;
$pos —;
for ($j=0; $j<$pos; $j ) {
$result .= $indentStr;
}
}

// Add the character to the result string
$result .= $char;

// If the last character was the beginning of an element,
// output a new line and indent the next line
if ($char ‘,’ || $char ‘{’ || $char ‘[‘) {
$result .= $newLine;
if ($char ‘{’ || $char == ‘[’) {
$pos ;
}
for ($j = 0; $j
4 Mithun Dhali 2009/05/15 20:49

There is an major issue with the code. It does not take into consideration string escaping.

If a string value (inside quotes) has ‘,’ (COMMA) in it, it simply puts a newline after it. When doing an eval, this will give an unterminated error.

Example input:
code”:”“}

Example output: (Note that in the value html an unwanted newline is added after COMMA.)
{
code”,
success,
params
part”,
entity”,
html”
}
}

The code may work for simple strings, however it will give unexpected errors for complex data in string values.

recurser

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4 Responses to “Format JSON with PHP”

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