Various Subscription and Transaction status hooks for MemberPress with some helpful comments

memberpress-hooks.php

<?php
//Capture a new member signup. Only ever triggers once for each new member.
//Does not trigger for exising members who have subscribed to a Membership before.
//
//The user may not be logged in when this is called
//as it is triggered when a user is added over the REST API,
//and also when a user is added from the dashboard (MemberPress -> Members -> Add New)
function mepr_capture_new_member_signup_completed($event) {
  $user = $event->get_data();
  $txn_data = json_decode($event->args);

  //Do what you need
}
add_action('mepr-event-member-signup-completed', 'mepr_capture_new_member_signup_completed');


//Capture a new Recurring Subscription created event
function mepr_capture_new_recurring_sub($event) {
  $subscription = $event->get_data();
  $user = $subscription->user();
  //Do what you need
}
add_action('mepr-event-subscription-created', 'mepr_capture_new_recurring_sub');


//Capture any completed transaction (recurring and non-recurring) event
function mepr_capture_completed_transaction($event) {
  $transaction = $event->get_data();
  $user = $transaction->user();
  
  if(($subscription = $transaction->subscription_id)) {
    $subscription_number = $subscription->subscr_id;
    //This transaction belongs to a recurring subscription
  }
  else {
    $transaction_number = $transaction->trans_num;
    //This is a non-recurring transaction
  }
  
  //Do what you need
}
add_action('mepr-event-transaction-completed', 'mepr_capture_completed_transaction');


//Capture a new One-Time Subscription created event
function mepr_capture_new_one_time_sub($event) {
  $transaction = $event->get_data();
  $user = $transaction->user();
  //Do what you need
}
add_action('mepr-event-non-recurring-transaction-completed', 'mepr_capture_new_one_time_sub');


//Capture a Recurring Subscription paused event
function mepr_capture_paused_sub($event) {
  $subscription = $event->get_data();
  $user = $subscription->user();
  //Do what you need
}
add_action('mepr-event-subscription-paused', 'mepr_capture_paused_sub');


//Capture a Recurring Subscription resumed event
function mepr_capture_resumed_sub($event) {
  $subscription = $event->get_data();
  $user = $subscription->user();
  //Do what you need
}
add_action('mepr-event-subscription-resumed', 'mepr_capture_resumed_sub');


//Capture a Recurring Subscription cancelled event (and detect who did it)
function mepr_capture_stopped_sub($event) {
  $subscription = $event->get_data();
  $user = $subscription->user();
  
  if(is_user_logged_in()) {
    if(current_user_can('manage_options')) {
      //An admin cancelled this from the dashboard
    }
    else {
      //User cancelled from their account page or upgraded to a new plan
    }
  }
  else {
    //Cancelled from a gateway Webhook or IPN notification
    //Not really a way to tell why but it could have been an
    // - admin cancelling it at the gateway instead of in the dashboard
    // - or the gateway could have cancelled it because of too many failed payments
    // - or the gateway could have cancelled it because the max billing cycles was reached
    // - or in the case of PayPal a user might have cancelled their recurring profile from in their PayPal account
  }
}
add_action('mepr-event-subscription-stopped', 'mepr_capture_stopped_sub');


//Capture a failed Transaction event
function mepr_capture_failed_transaction($event) {
  $transaction = $event->get_data();
  $subscription = $transaction->subscription();
  $user = $transaction->user();
  //Do what you need
}
add_action('mepr-event-recurring-transaction-failed', 'mepr_capture_failed_transaction');


//Capture a one-time completed Transaction event
//See mepr_capture_new_one_time_sub() above


//Capture a recurring completed Transaction event
function mepr_capture_completed_recurring_transaction($event) {
  $transaction = $event->get_data();
  $subscription = $transaction->subscription();
  $user = $transaction->user();
  //Do what you need
}
add_action('mepr-event-recurring-transaction-completed', 'mepr_capture_completed_recurring_transaction');


//Capture a refunded Transaction event
function mepr_capture_refunded_transaction($event) {
  $transaction = $event->get_data();
  $subscription = $transaction->subscription(); //This may return false if it's a one-time transaction that was refunded
  $user = $transaction->user();
  //Do what you need
}
add_action('mepr-event-transaction-refunded', 'mepr_capture_refunded_transaction');


//Capture a Transaction expired event
function mepr_capture_expired_transaction($event) {
  //BE CAREFUL WITH THIS ONE
  //This could be a prior recurring transaction that has expired
  //So the user might still be active on the subscription with a new transaction
  //So you might check
  // - if the $subscription exists
  // - if so, then is $subscription->status = 'active' still
  // - if so, then it's possible the user is not really expired on it
  //   - to check this use the $user->is_already_subscribed_to($transaction->product_id) method
  $transaction = $event->get_data();
  $subscription = $transaction->subscription(); //This may return false if it's a one-time transaction that has expired
  $user = $transaction->user();
  //Do what you need
}
add_action('mepr-event-transaction-expired', 'mepr_capture_expired_transaction');


//Capture a signup (user completed step 1, but hasn't necessarily paid yet)
function mepr_capture_new_member_added($event) {
  $user = $event->get_data();
  //Do what you need
}
add_action('mepr-event-member-added', 'mepr_capture_new_member_added');

None of the completed transaction actions seem to fire when a pending transaction is marked complete (standard Offline Payment Gateway procedure).

Is this still valid? I am not sure they are firing at all

They are event hooks only. These are event fired and sent to a predefined webhook url and do not work called as normal WordPress actions/filters.

For completed transaction this one works:

function track_completed_transaction($event) {
  $data = $event->get_data();
  $user = $data->user();
  $membership = $data->product();
}
add_action( 'mepr-txn-status-complete', 'track_completed_transaction', 10, 1 );