PHP - warning - Undefined property: stdClass - fix? [duplicate] - php

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PHP check whether property exists in object or class
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I get this warning in my error logs and wanted to know how to correct this issues in my code.
Warning:
PHP Notice: Undefined property: stdClass::$records in script.php on line 440
Some Code:
// Parse object to get account id's
// The response doesn't have the records attribute sometimes.
$role_arr = getRole($response->records); // Line 440
Response if records exists
stdClass Object
(
[done] => 1
[queryLocator] =>
[records] => Array
(
[0] => stdClass Object
(
[type] => User
[Id] =>
[any] => stdClass Object
(
[type] => My Role
[Id] =>
[any] => <sf:Name>My Name</sf:Name>
)
)
)
[size] => 1
)
Response if records does not exist
stdClass Object
(
[done] => 1
[queryLocator] =>
[size] => 0
)
I was thinking something like array_key_exists() functionality but for objects, anything? or am I going about this the wrong way?

Answer 1

if(isset($response->records))
print "we've got records!";

Answer 2

isset() is fine for top level, but empty() is much more useful to find whether nested values are set. Eg:
if(isset($json['foo'] && isset($json['foo']['bar'])) {
$value = $json['foo']['bar']
}
Or:
if (!empty($json['foo']['bar']) {
$value = $json['foo']['bar']
}

Answer 3

In this case, I would use:
if (!empty($response->records)) {
// do something
}
You won't get any ugly notices if the property doesn't exist, and you'll know you've actually got some records to work with, ie. $response->records is not an empty array, NULL, FALSE, or any other empty values.

Answer 4

You can use property_exists
http://www.php.net/manual/en/function.property-exists.php

Answer 5

If you want to use property_exists, you'll need to get the name of the class with get_class()
In this case it would be :
if( property_exists( get_class($response), 'records' ) ){
$role_arr = getRole($response->records);
}
else
{
...
}

Answer 6

Error control operator
In case the warning is expected you can use the error control operator # to suppress thrown messages.
$role_arr = getRole(#$response->records);
While this reduces clutter in your code you should use it with caution as it may make debugging future errors harder. An example where using # may be useful is when creating an object from user input and running it through a validation method before using it in further logic.
Null Coalesce Operator
Another alternative is using the isset_ternary operator ??. This allows you to avoid warnings and assign default value in a short one line fashion.
$role_arr = getRole($response->records ?? null);

Answer 7

The response itself seems to have the size of the records. You can use that to check if records exist. Something like:
if($response->size > 0){
$role_arr = getRole($response->records);
}

Answer 8

If think this will work:
if(sizeof($response->records)>0)
$role_arr = getRole($response->records);
newly defined proprties included too.