Unable to recreate object from var_exported data (in PHP) - php

Question

A script running on on our live server sends out data from the following line:
$log_output .= '<br>'.__LINE__.'<br>recordings_data='.var_export($recordings_data,TRUE);
Which looks like this:
recordings_data=stdClass::__set_state(array( 'RecordingLongResponse'
=> array ( 0 => stdClass::__set_state(...), 1 => stdClass::__set_state(), 2 => stdClass::__set_state(), 3 =>
stdClass::__set_state(array( 'roomStartDate' => '1321977120000',
'roomEndDate' => '1321977120000', 'recordingURL' => 'serverURL1',
'secureSignOn' => false, 'recordingId' => '1287268130290',
'creationDate' => '1321977120000', 'recordingSize' => '6765975',
'roomName' => 'Stakeholder Analysis', 'sessionId' => '1287268130229',
)), ...), ))
I'm not sure how to 'recreate' the object. I tried unserializing it:
$recording_data_ser= file_get_contents('elm-ser-data.txt'); // where I've saved everything after the '='
$recording_data = unserialize($recording_data_ser);

Answer 1

serialize() and unserialize() are the generally accepted methods for dumping/loading PHP objects. You can also do it with json_encode() and json_decode(). Is there a reason you want to use var_export()?
Edit: you can only unserialize() the result of serialize() - var_dump() is in a completely different format and isn't designed for importing unless you use eval().
For example:
$arr = array('foo' => 'bar');
var_export($arr);
#=> array (
#=> 'foo' => 'bar',
#=> )
echo serialize($arr);
#=> a:1:{s:3:"foo";s:3:"bar";}
echo json_encode($arr);
#=> {"foo":"bar"}
Once you have the serialized data (via serialize() or json_encode()), you can use the opposite method (unserialize() or json_decode(), respectively) to recreate the object again.

Answer 2

var_export() is intended to dump a data structure to a file. You then have to eval() or include() or require() that file. the serialize() format is completely different from var_export.
var_export produces valid PHP code to define a data structure, as if you'd written out the array/object definition yourself. serialize/unserialize write out in a completely different format, and they're not interchangeable.

Answer 3

If you call var_export() on an instance of stdClass, it attempts to export it using ::__set_state(), which, for some reason, is not implemented in stdClass.
However, casting an associative array to an object usually produces the same effect (at least, it does in my case). So I wrote an improved_var_export() function to convert instances of stdClass to (object) array () calls. If you choose to export objects of any other class, I'd advise you to implement ::__set_state() in those classes.
<?php
/**
* An implementation of var_export() that is compatible with instances
* of stdClass.
* #param mixed $variable The variable you want to export
* #param bool $return If used and set to true, improved_var_export()
* will return the variable representation instead of outputting it.
* #return mixed|null Returns the variable representation when the
* return parameter is used and evaluates to TRUE. Otherwise, this
* function will return NULL.
*/
function improved_var_export ($variable, $return = false) {
if ($variable instanceof stdClass) {
$result = '(object) '.improved_var_export(get_object_vars($variable), true);
} else if (is_array($variable)) {
$array = array ();
foreach ($variable as $key => $value) {
$array[] = var_export($key, true).' => '.improved_var_export($value, true);
}
$result = 'array ('.implode(', ', $array).')';
} else {
$result = var_export($variable, true);
}
if (!$return) {
print $result;
return null;
} else {
return $result;
}
}
// Example usage:
$obj = new stdClass;
$obj->test = 'abc';
$obj->other = 6.2;
$obj->arr = array (1, 2, 3);
improved_var_export((object) array (
'prop1' => true,
'prop2' => $obj,
'assocArray' => array (
'apple' => 'good',
'orange' => 'great'
)
));
/* Output:
(object) array ('prop1' => true, 'prop2' => (object) array ('test' => 'abc', 'other' => 6.2, 'arr' => array (0 => 1, 1 => 2, 2 => 3)), 'assocArray' => array ('apple' => 'good', 'orange' => 'great'))
*/
// Example implementation in context of OP
$export = improved_var_export($data, true);
file_put_contents(dirname(__FILE__).'/data.php', '<'.'?php return '.$export.'; ?'.'>');
// "Unserialization" (evaluation)
$import = include dirname(__FILE__).'/data.php';
?>