PHP deep clone object - php

Question

The scenario: fetch an email template from the database, and loop through a list of recipients, personalising the email for each.
My email template is returned as a nested object. It might look a little like this:
object(stdClass) {
["title"] => "Event Notification"
["sender"] => "notifications#mysite.com"
["content"] => object(stdClass) {
["salutation"] => "Dear %%firstname%%,"
["body"] => "Lorem ipsum %%recipient_email%% etc etc..."
}
}
Then I loop through the recipients, passing this $email object to a personalise() function:
foreach( $recipients as $recipient ){
$email_body = personalise( $email, $recipient );
//send_email();
}
The issue, of course, is that I need to pass the $email object by reference in order for it to replace the personalisation tags - but if I do that, the original object is changed and no longer contains the personalisation tags.
As I understand, clone won't help me here, because it'll only create a shallow copy: the content object inside the email object won't be cloned.
I've read about getting round this with unserialize(serialize($obj)) - but everything I've read says this is a big performance hit.
So, two finally get to my two questions:
Is unserialize(serialize($obj)) a reasonable solution here?
Or am I going about this whole thing wrong? Is there a different way that I
can generate personalised copies of that email object?

Answer 1

You could add a __clone() method to your email class. Which is automatically called when an instance of this class is cloned via clone(). In this method you can then manually add the template.
Example:
class Email {
function __clone() {
$this->template = new Template();
}
}
.
unserialize(serialize($object)); // would be another solution...

Answer 2

Another more generic and powerful solution: MyCLabs\DeepCopy.
It helps creating deep copy without having to overload __clone (which can be a lot of work if you have a lot of different objects).

Answer 3

Recursive cloning can be done this way:
public function __clone(): void {
foreach(get_object_vars($this) as $name => $value)
if(is_object($value)) $this->{$name} = clone $value;
}

Answer 4

Not sure why it's not mentioned here, but the keyword clone before the object does exactly what it says.
Here's an example:
// Prepare shared stream data
$args = (object) [
'key' => $key,
'data_type' => $data_type,
'data' => clone $data_obj,
'last_update' => $last_update
];
setSharedStreamData($args);
// Object below will not change when data property
// is updated in setSharedStreamData function
print_r($data_obj);