php JSON 数据格式化函数

将字符串形式的 JSON 数据格式化为缩进形式。通常使用 json_encode 转换出来的 JSON 串没有缩进。
有了本文分享的这个方法，就不用再担心这个问题了。
本代码：
默认使用了 tab 缩进，如果要改成空格，替换变量 $indentStr 即可。

代码：

<?php
/**
* Indents a flat JSON string to make it more human-readable.
* @param string $json The original JSON string to process.
* @return string Indented version of the original JSON string.
* @site www.jb200.com
*/
function indent ($json) {
 $result = '';
 $pos = 0;
 $strLen = strlen($json);
 $indentStr = ' ';
 $newLine = "n";
 $prevChar = '';
 $outOfQuotes = true;

 for ($i=0; $i<=$strLen; $i++) {
  // Grab the next character in the string.
  $char = substr($json, $i, 1);
  // Are we inside a quoted string?
  if ($char == '"' && $prevChar != '') {
   $outOfQuotes = !$outOfQuotes;
   // If this character is the end of an element,
   // output a new line and indent the next line.
  } else if(($char == '}' || $char == ']') && $outOfQuotes) {
   $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 == '[') && $outOfQuotes) {
   $result .= $newLine;
   if ($char == '{' || $char == '[') {
    $pos ++;
   }
   for ($j = 0; $j < $pos; $j++) {
    $result .= $indentStr;
   }
  }
  $prevChar = $char;
 }
 return $result;
}
?>