Wordpress - create route to action in plugin - php

Question

I want to create a route in my wordpress plugin that isn't linked to a page but to an action that sends an email. So i would send a get request like this
example.com/send/email?email=test#test.co.uk
and this would link to an action with the email as a parameter. I'm very new to Wordpress so forgive me if this is a stupid question but I'm really struggling to achieve this or evebn find a good starting point, can anyone help?

Answer 1

A good option in your case would be to use a rewrite endpoint. A rewrite endpoint allows you to add extra query parameters to certain URLs. For instance you can add a gallery endpoint to all posts, that could render a different template showing all images for the given post. More information about add_rewrite_endpoint() can be seen in the Codex.
Below is some code that adds a send endpoint to EP_ROOT(the home page of the site). Note that you'll have to go to Settings > Permalinks after adding this code in order for the rewrite endpoint to start working.
Once we have the rewrite endpoint in place, we hook to the template_redirect action in order to check for the presence of the send query var. If send is not present, then we do nothing.
If send is present, but empty(like for instance if you load the page http://example.com/send/), then we redirect to the home page.
Otherwise we split send into multiple parts at every / and assign that to the $send_parts variable. We then use a switch statement to see what the $send_action(the first part after /send/) and act accordingly.
Right now we're only checking for the email action(if it's not email, we redirect to the home page again). We check if there's an actual email($send_parts[1]) and whether it's a valid email(I have to note that is_email() is not RFC compliant and it might reject valid email addresses, so use with caution). If it's a valid email, we use wp_mail() to send the email, otherwise we redirect to the home page.
Now, since I don't know how you're planning to implement this my code doesn't cover things like authentication(who can send emails - if it's everyone, I can abuse your site and spam users and get your mail server blacklisted - bad :( ), generation of the email Subject and Message(is it going to be dynamic via $_POST variables, is it going to be pre-defined, etc.). Those are specifics that you will have to implement on your own.
Once the code below is placed in an appropriate file(a .php file that gets loaded in the current theme, or an active plugin's file) and you regenerate your Rewrite Rules(by going to Settings > Permalinks), you can go to http://example.com/send/email/your.email#example.com/ and you should receive an email with a subject "Hello" and a message "This is a message".
function so_34002145_add_email_endpoint() {
add_rewrite_endpoint( 'send', EP_ROOT );
}
add_action( 'init', 'so_34002145_add_email_endpoint', 10 );
function so_34002145_handle_send_email() {
$send = get_query_var( 'send', null );
// This is not a /send/ URL
if ( is_null( $send ) ) {
return;
}
// We're missing an action, the URL is /send/
// Take the user to the home page, since this is an incomplete request.
if ( empty( $send ) ) {
wp_redirect( home_url( '/' ) );
exit;
}
$send_parts = explode( '/', $send );
$send_action = $send_parts[0];
switch ( $send_action ) {
case 'email':
$email = ! empty( $send_parts[1] ) ? $send_parts[1] : false;
if ( ! $email || ! is_email( $email ) ) {
// A missing or invalid email address, abort
wp_redirect( home_url( '/' ) );
exit;
}
wp_mail( $email, 'Hello', 'This is a message' );
break;
default:
// This is an unknown action, send to the home page
wp_redirect( home_url( '/' ) );
exit;
break;
}
}
add_action( 'template_redirect', 'so_34002145_handle_send_email', 10 );