Convert print_r result to JSON

As you know json_encode is encoding only array or public properties of an object. But print_r can expose the protected and private properties in an object. Sometimes we need to these hidden properties. For this purpose we can convert print_r result to JSON result. Here is the function we need:

if (!function_exists('pr2json')) {
  /**
   * Convert print_r result to json string.
   * @note Exceptions are always there i tried myself best to get it done. Here $array can be array of arrays or arrays of objects or both
   * @param string $string Result of `print_r($array, true)`
   * @return string Json string (transformed version of print_r result)
   */
  function pr2json($string)
  {
    // replacing `stdClass Objects (` to  `{`
    $string = preg_replace("/stdClass Object\s*\(/s", '{  ', $string);

    // replacing `Array (` to  `{`
    $string = preg_replace("/Array\s*\(/s", '{  ', $string);

    // replacing `)\n` to  `},\n` @note This might append , at the last of string as well which we will trim later on.
    $string = preg_replace("/\)\n/", "},\n", $string);

    // replacing `)` to  `}` at the last of string
    $string = preg_replace("/\)$/", '}', $string);

    // replacing `[ somevalue ]` to "somevalue"
    $string = preg_replace("/\[\s*([^\s\]]+)\s*\](?=\s*\=>)/", '"\1" ', $string);

    // replacing `=> {`  to `: {`
    $string = preg_replace("/=>\s*{/", ': {', $string);

    // replacing empty last values of array special case `=> \n }` to : "" \n
    $string = preg_replace("/=>\s*[\n\s]*\}/s", ":\"\"\n}", $string);

    // replacing `=> somevalue`  to `: "somevalue",`
    $string = preg_replace("/=>\s*([^\n\"]*)/", ':"\1",', $string);

    // replacing last mistakes `, }` to `}`
    $string = preg_replace("/,\s*}/s", '}', $string);

    // replacing `} ,` at the end to `}`
    return $string = preg_replace("/}\s*,$/s", '}', $string);
  }
}

This is generating well formed JSON string. We can convert this to a json object and then access the private/protected properties of an object.

$jsonObj = json_decode( pr2json( $privateObj ) );

Pros and Cons

print_r is dumping all data. Sometimes data can be bigger then you though and this causes a memory error. When you try to convert a big class to json string then you can face some memory issues. And the other hand normally you don’t need to private/protected properties in an object. There must be a way for accessing to private property or you don’t need it really. Actually if you try to access a private/protected property then may be you’re acting out of engineering methods.

Happy coding…