Sequence of admin_post and admin_menu

@threadi From the doc

Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP.

Normally, we will have another file/script to handle the form like, right?
Assume index.php has a form and it looks like this:


<form action="process.php" method="post"></form>

Then in the process.php file, we use $_POST to get the data like this ( call this “example-1” for later reference ):


$name = $_POST['name'];

header ( "Location: https://example.com" ); // Redirect user to https://example.com after processing the data.

But if we put the processing code above on the same file ( index.php ) and it looks like this ( call this “example-2” for later reference ):


<form action="process.php" method="post"></form>

<?php
$name = $_POST['name'];

header ( "Location: https://example.com" );
?>

It would cause an error because there is already an output ( the form ) before the header ().

Now let’s get back to the “WordPress” way of handling form, we will use the hook admin_post_{$action} with a function like:


add_action( admin_post_handle_data, handle_data );

Then we write the processing code inside handle_data like the below:


function handle_data () {
   $name = $_POST['name'];

   header ( "Location: https://example.com" );
}

The form page is created by add_menu_page with the admin_menu hook.

My question is:
1) Will this function handle_data () be include/require on the form page? If it does, it will look like the “example-2”.

2) If the question “1)” is a yes, then the sequence matter, whether it’s admin_post first or admin_menu first. If it’s admin_post first, then the function handle_data () is before the form; If it’s the admin_menu first, then the function handle_data () is after the form.

Or am I complicating it, WordPress will just do the traditional way like “example-1” where the processing code is in another script/file?

  • This reply was modified 58 minutes ago by ace0930.

 

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