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We have a post hook that sends some data to an external api when a participant is created or edited.

function kavo_civicrm_post($op, $objectName, $objectId, &$objectRef) { if (($op == 'create' || $op == 'edit') && $objectName == 'Participant') {

Based on the response of that api a custom field on the response of that API a couple of custom fields on the participant should be set. This is done using the php api, but results in a loop with the post hook being called, even when following the add_callback instructions in the post hook documentation.

try { civicrm_api3('Kavo', 'createparticipant', ['participant_id' => $objectId]); $successState = CRM_Kavo_Status::KAVO_ATTENDED(); CRM_Core_Transaction::addCallback(CRM_Core_Transaction::PHASE_POST_COMMIT, 'set_kavo_state', [$objectId, $successState]); } catch (CiviCRM_API3_Exception $ex) { $contact = $worker->getContact($participant); CRM_Core_Session::setStatus($ex->getMessage(), ts("Failed sending participant %1 to KAVO.", [1 => $contact['display_name']]), 'error'); $failedState = CRM_Kavo_Status::KAVO_FAILED(); CRM_Core_Transaction::addCallback(CRM_Core_Transaction::PHASE_POST_COMMIT, 'set_kavo_state', [$objectId, $failedState, $ex->getMessage()]); }

function set_kavo_state($participant_id, $state, $message='success'){ $kavo_status_field = CRM_Kavo_Field::KAVO_PARTICIPANT_STATUS(); $kavo_message_field = CRM_Kavo_Field::KAVO_PARTICIPANT_MESSAGE(); civicrm_api3('Participant', 'create', array( 'id' => $participant_id, $kavo_status_field => $state, $kavo_message_field => $message )); }

The kavo create_participant call does our call to the external api Is there another way to edit the participant being edited in a post hook?

  • I am not clear on what you are asking, can you give a little more detail? I think I understand (and know the problem) but I am not sure..... – ErikH - CiviCooP Sep 21 '17 at 11:35
  • In a post hook we send a request to an external api. This post hook is limited to working on particapants on edit or create. Depending on the succes of the api call I want to set a costum field on the participant. I will edit some code in the original question to clarify. – joost Sep 21 '17 at 11:47
1

The participant create in set_kavo_state() triggers your post hook again which then calls set_kavo_state() etc. You need to determine whether the post hook is being called just to update the $kavo_status_field and $kavo_message_field fields - and therefore not set up another callback to set_kavo_state().

Do you actually need to call your external API for participant edits? If you could limit the post hook to only trigger on 'create' you would avoid the loop.

  • The external api needs to be called when participants are edited, and their kavo fields need to be set based on the api response. I know the call to set the kavo fiels is the reason for getting in the loop, I was wondering wether there was a way to set them without getting back in the post hook. – joost Sep 22 '17 at 8:48
  • I think that if you check your request in the post hook you can determine if you are coming in from the API or not? – ErikH - CiviCooP Apr 20 '18 at 12:16
1

You have two choices:

  • Use hook_civicrm_pre instead of hook_civirm_post. This isn't ideal because it's synchronous and will slow down your writes.
  • Since you're updating custom fields only, continue to use hook_civicrm_post, but instead of calling Participant.create, call CustomValue.create, which won't trigger the post hook a second time.
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If you are using Drupal, you can use the Drupal static cache infrastructure to break the cycle. In this particular example, the static cache is only available for one page load / http request. You can set a database cache as well, see References below for detailed explanation and instructions

function set_kavo_state($participant_id, $state, $message='success'){
  $stop = &drupal_static(__FUNCTION__);
  // could use more logic in this conditional if need be ... but at least you will know if you've come back a second time...
  if (!isset($stop)) {
    $kavo_status_field = CRM_Kavo_Field::KAVO_PARTICIPANT_STATUS();
    $kavo_message_field = CRM_Kavo_Field::KAVO_PARTICIPANT_MESSAGE();
    civicrm_api3('Participant', 'create', array(
      'id' => $participant_id,
      $kavo_status_field => $state,
      $kavo_message_field => $message
    ));
    $stop = 1;
  }
}

References: Drupal API documentation A Beginner's Guide to Caching Data in Drupal 7

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