JsonPath.php

<?php

/* JSONPath 0.8.3 - XPath for JSON
 *
 * Copyright (c) 2007 Stefan Goessner (goessner.net)
 * Licensed under the MIT (MIT-LICENSE.txt) licence.
 */

namespace Goessner\JsonPath;

class JsonPath
{

    var $obj = null;
    var $resultType = "Value";
    var $result = array();
    var $subx = array();

    public function query($obj, $expr, $args = null)
    {
        $this->resultType = ($args ? $args['resultType'] : "VALUE");
        $x = $this->normalize($expr);
        $this->obj = $obj;
        if ($expr && $obj && ($this->resultType == "VALUE" || $this->resultType == "PATH")) {
            $this->trace(preg_replace("/^\\$;/", "", $x), $obj, "$");
            if (count($this->result))
                return $this->result;
            else
                return false;
        }
    }

    // normalize path expression
    function normalize($x)
    {
        $x = preg_replace_callback(array("/[\['](\??\(.*?\))[\]']/", "/\['(.*?)'\]/"), array(&$this, "_callback_01"), $x);
        $x = preg_replace(array("/'?\.'?|\['?/", "/;;;|;;/", "/;$|'?\]|'$/"), array(";", ";..;", ""), $x);
        $x = preg_replace_callback("/#([0-9]+)/", array(&$this, "_callback_02"), $x);
        $this->result = array();  // result array was temporarily used as a buffer ..
        return $x;
    }

    function _callback_01($m)
    {
        return "[#" . (array_push($this->result, $m[1]) - 1) . "]";
    }

    function _callback_02($m)
    {
        return $this->result[$m[1]];
    }

    function asPath($path)
    {
        $x = explode(";", $path);
        $p = "$";
        for ($i = 1, $n = count($x); $i < $n; $i++)
            $p .= preg_match("/^[0-9*]+$/", $x[$i]) ? ("[" . $x[$i] . "]") : ("['" . $x[$i] . "']");
        return $p;
    }

    function store($p, $v)
    {
        if ($p)
            array_push($this->result, ($this->resultType == "PATH" ? $this->asPath($p) : $v));
        return !!$p;
    }

    function trace($expr, $val, $path)
    {
        if ($expr !== "") {
            $x = explode(";", $expr);
            $loc = array_shift($x);
            $x = implode(";", $x);

            if (is_array($val) && array_key_exists($loc, $val))
                $this->trace($x, $val[$loc], $path . ";" . $loc);
            else if ($loc == "*")
                $this->walk($loc, $x, $val, $path, array(&$this, "_callback_03"));
            else if ($loc === "..") {
                $this->trace($x, $val, $path);
                $this->walk($loc, $x, $val, $path, array(&$this, "_callback_04"));
            } else if (preg_match("/^\(.*?\)$/", $loc)) // [(expr)]
                $this->trace($this->evalx($loc, $val, substr($path, strrpos($path, ";") + 1)) . ";" . $x, $val, $path);
            else if (preg_match("/^\?\(.*?\)$/", $loc)) // [?(expr)]
                $this->walk($loc, $x, $val, $path, array(&$this, "_callback_05"));
            else if (preg_match("/^(-?[0-9]*):(-?[0-9]*):?(-?[0-9]*)$/", $loc)) // [start:end:step]  phyton slice syntax
                $this->slice($loc, $x, $val, $path);
            else if (preg_match("/,/", $loc)) // [name1,name2,...]
                for ($s = preg_split("/'?,'?/", $loc), $i = 0, $n = count($s); $i < $n; $i++)
                    $this->trace($s[$i] . ";" . $x, $val, $path);
        }
        else
            $this->store($path, $val);
    }

    function _callback_03($m, $l, $x, $v, $p)
    {
        $this->trace($m . ";" . $x, $v, $p);
    }

    function _callback_04($m, $l, $x, $v, $p)
    {
        if (is_array($v[$m]))
            $this->trace("..;" . $x, $v[$m], $p . ";" . $m);
    }

    function _callback_05($m, $l, $x, $v, $p)
    {
        if ($this->evalx(preg_replace("/^\?\((.*?)\)$/", "$1", $l), $v[$m]))
            $this->trace($m . ";" . $x, $v, $p);
    }

    function walk($loc, $expr, $val, $path, $f)
    {
        foreach ($val as $m => $v)
            call_user_func($f, $m, $loc, $expr, $val, $path);
    }

    function slice($loc, $expr, $v, $path)
    {
        $s = explode(":", preg_replace("/^(-?[0-9]*):(-?[0-9]*):?(-?[0-9]*)$/", "$1:$2:$3", $loc));
        $len = count($v);
        $start = (int) $s[0] ? $s[0] : 0;
        $end = (int) $s[1] ? $s[1] : $len;
        $step = (int) $s[2] ? $s[2] : 1;
        $start = ($start < 0) ? max(0, $start + $len) : min($len, $start);
        $end = ($end < 0) ? max(0, $end + $len) : min($len, $end);
        for ($i = $start; $i < $end; $i+=$step)
            $this->trace($i . ";" . $expr, $v, $path);
    }

    function evalx($x, $v, $vname)
    {
        $name = "";
        $expr = preg_replace(array("/\\$/", "/@/"), array("\$this->obj", "\$v"), $x);
        $res = eval("\$name = $expr;");

        if ($res === FALSE)
            print("(jsonPath) SyntaxError: " . $expr);
        else
            return $name;
    }

}

?>