How to check if JSON object is empty in PHP? - php

Question

I'm reading JSON data with PHP and that data contains empty objects (like {}). So the problem is, I have to handle the case when object is empty in different manner but I can't find good enough way to do the check. empty(get_object_vars(object)) looks too scary and very inefficient. Is there good way to do the check?

Answer 1

How many objects are you unserializing? Unless empty(get_object_vars($object)) or casting to array proves to be a major slowdown/bottleneck, I wouldn't worry about it – Greg's solution is just fine.
I'd suggest using the the $associative flag when decoding the JSON data, though:
json_decode($data, true)
This decodes JSON objects as plain old PHP arrays instead of as stdClass objects. Then you can check for empty objects using empty() and create objects of a user-defined class instead of using stdClass, which is probably a good idea in the long run.

Answer 2

You could cast it to an array (unfortunately you can't do this within a call to empty():
$x = (array)$obj;
if (empty($x))
...
Or cast to an array and count():
if (count((array)$obj))
...

Answer 3

Try without using empty() which is:
get_object_vars($obj) ? TRUE : FALSE;
On PHP docs we can read the note:
When using empty() on inaccessible object properties, the __isset() overloading method will be called, if declared.
Which means when using empty() on an object which is having __get() method, it will always return True.

Answer 4

I had to tell if an object was empty or not, but I also had to ignore private and protected properties, so I made this little function with which you can do this.
function empty_obj(&$object, $ignore_private = true, $ignore_protected = true) {
$obj_name = get_class($object);
$obj = (array)$object;
foreach(array_keys($obj) as $prop) {
$is_private = $is_protected = false;
$prop = preg_replace("/[^\w*]/", '', $prop);
$prop_name = str_replace(array($obj_name, '*'), '', $prop);
if(preg_match("~^$obj_name$prop_name$~", $prop))
$is_private = true;
if(preg_match("~^\*$prop_name$~", $prop))
$is_protected = true;
if(!$is_private || !$is_protected || ($is_private && !$ignore_private) || ($is_protected && !$ignore_protected))
return;
}
return true;
}

Answer 5

I am not sure if this is more or less effective than casting to an array but I would guess more. You could just start to loop the object and as soon as you find something you have an answer and stop looping.
function is_obj_empty($obj){
if( is_null($obj) ){
return true;
}
foreach( $obj as $key => $val ){
return false;
}
return true;
}