Send e-mail from admin area to adresses in custom field

Question

My client wants to be able to send an e-mail from the Page Editing Screen to a number of e-mail addresses. Every page has a custom field called email_addresses that takes comma seperated addresses:

Every page will have a different set of addresses. I need a textarea below this field in which my client can enter the body of the email and a submit button below that to actually send the email.

I've added a form with a textarea and a submit form to the Page Editing Screen page using the add_meta_box() function:

    // Add metabox
    function metabox_after_publish() {
       add_meta_box( 'send-email', 'Send E-mail', 'send_email_metabox_content', 'page', 'advanced', 'high' );
    }
    add_action( 'add_meta_boxes', 'metabox_after_publish' );

    // callback function to populate metabox
    function send_email_metabox_content() { ?>
        <form>
             <textarea id="email_content" style="width:100%" rows="6"></textarea>
             <p><input id="email_send_button" type="submit" class="button button-primary button-large" value="Send" /></p>
        </form>
    <?php }

How can I make the form function so it sends the content of the textarea to the email addresses in the custom field?

Answer 1

First, decide whether you want to use GET or POST for your form. (without specifying the method, it will use GET.)

You will need the name attribute filled out for your textarea, so the info can actually be sent. Then add your form processing into your function:

(i.e. if ( isset($_POST["message"]) && !empty($_POST["message"]) ) {...} )

You will need to use get_post_meta( get_the_ID(), 'email_addresses' ) to retrieve the email addresses from the custom field. Store that value in a string variable. You will want to separate out the email addresses into an array (beware of the space - you should make sure your client knows if they should or shouldn't have a space after the commas).

Then, you'll need to loop through the array with a foreach, (because the PHP mail() function's $to parameter does not accept arrays, only strings). You can build out your email form processing like the examples on this page.

Hope this helps! Let me know if you need any clarification.