How to load WP functions?

Question

I have a mymail.php script which sends a email (I managed to do it using require_once( $_SERVER['DOCUMENT_ROOT'] . '/wp-includes/class-phpmailer.php' );.) and outputs a plain text string (Such as "Email is sent successfully.")

I want to use the functions defined in WP in this my script. The particular function I want to call is get_option() in order to retrieve the email user of the site owner. Which file to import for the particular get_option() function and which to import the entire WP core (like the context available for theme's .php files?

Answer 1

Put this near the top of your PHP file:

require_once('wp-blog-header.php');

You may also want to reduce wordpress core load by defining SHORT_INIT, though this depends on which functions you are using ( and wether they get loaded when this is defined ).

But this is completely the wrong way of going about it. Because its:

• more effort
• wasteful
• slower
• less secure
• likely to incurr a higher maintenance and support cost

Judging from your comment, I would advise you use the WP AJAX APIs instead, see here:

http://codex.wordpress.org/Plugin_API/Action_Reference/wp_ajax_(action)

Using these APIs will save you time and effort, and it will make things simpler/easier in the longrun ( and more secure )

e.g.

// PHP ( functions.php )
add_action('wp_ajax_mymail', 'mymail');

function mymail() {
    // send email
    echo "Success email sent";
    return;
}

and

// js
jQuery.post(
   ajaxurl, 
   {
      'action':'mymail',
      'data':'the form submission data'
   }, 
   function(response){
      alert('The server responded: ' + response);
   }
);

Answer 2

mymail.php is located in the same dir where style.css and functions.php of the custom theme I am developing is located. It is executed from a .js file when a user clicks a submit button in a form of our theme. mymail.php is executed outside of WordPress.

So, basically, I think you've just answered your own question:

mymail.php is executed outside of WordPress.

Since the functionality is part of your Theme, there's no reason you can't/shouldn't execute mymail.php from within WordPress.

Have you considered using the wp_mail() function for your form submission?

Answer 3

define( 'WP_USE_THEMES', FALSE );
require( './wp-load.php' );

Use the defined constant to load faster and not all, waht WP have. You will use it on a custom mail function, but its not necessary, that you load all the functions for themes and the themes.

Alternative to wp-load.php you can also load the wp-blog-header.php, but the wp-load.php is the default file to load WP environment.

Also an hint, set the const define( 'SHORTINIT', TRUE ); to load much more less of files and WP faster. But check it; with this const load WP much smaller and only the important files. (see more information about this on my answer on other question)