How to get variables from fucntion.php to my plugin files

Question

I have written a function in functions.php that gets variables from a contact form and sends the inputs (and some other info like IP and location..) to my email.

I am starting to work on my first plugin and I want to store the parameters in a new table on the database.

How do I get the parameters from function.php right after the user clicks on the send button of the contact form?

Answer 1

There is three way to use function.php file variable into plugin file.

1. Using global. Make sure you globalize it first.

   global $my_variable; echo $my_variable;

2. I recommend is using WordPress built-in filter mechanism add_filter. You add the filter in your functions.php file and apply it where needed.

In functions.php:

add_filter( 'my_variable', 'return_my_variable' );
function return_my_variable( $arg = '' ) {
    return '111221122';
}

Now you can use in your plugin files:

echo apply_filters( 'my_variable', '' );

3. Use an action hook add_action

In functions.php:

add_action( 'my_variable', 'echo_my_variable' );
function echo_my_variable() {
    echo '888998899';
}

In your plugin files:

do_action( 'my_variable' );

Again, I recommend a filter because it can return a value. This is far more flexible than injecting echo calls in your plugin file. Whether you use an action hook or a filter is entirely up to you.

Answer 2

Basic PHP:

functions.php:

function my_func() {
   //doing my staff
   $my_var = 'data'; //stored data after doing things
   return $my_var;
}

In plugin file:

//retrieved data from a function declared within a system
$got_data = my_func();

function another_func( $got_data ) {
   //doing staff with $got_data
}