From 103e8994bf153ca74c09a3c10612f98329739835 Mon Sep 17 00:00:00 2001
From: Nick Ruest <ruestn@gmail.com>
Date: Wed, 11 May 2016 15:31:35 -0400
Subject: [PATCH] Message passing between drupal and camel. (#201)

* Message passing between drupal and camel updated for sprint-002
---
 islandora/include/admin.form.inc              | 61 ++++++++++++++
 islandora/include/rdf.inc                     | 21 +++++
 islandora/include/triplestore.inc             | 70 ++++++++++++++++
 islandora/include/utils.inc                   | 24 ++++++
 islandora/islandora.module                    | 79 +++++++++++++++++++
 .../islandora_basic_image.module              |  9 ++-
 .../islandora_collection.module               |  9 ++-
 7 files changed, 267 insertions(+), 6 deletions(-)
 create mode 100644 islandora/include/admin.form.inc
 create mode 100644 islandora/include/rdf.inc
 create mode 100644 islandora/include/triplestore.inc
 create mode 100644 islandora/include/utils.inc

diff --git a/islandora/include/admin.form.inc b/islandora/include/admin.form.inc
new file mode 100644
index 00000000..ce1d6592
--- /dev/null
+++ b/islandora/include/admin.form.inc
@@ -0,0 +1,61 @@
+<?php
+
+/**
+ * @file
+ * Admin form.
+ */
+
+/**
+ * Form function for module config.
+ *
+ * @param array $form
+ *   Drupal renderable array.
+ * @param array $form_state
+ *   Drupal form state.
+ *
+ * @return array
+ *   Final form to render.
+ */
+function islandora_config_form(array $form, array &$form_state) {
+  $form = array(
+    'islandora_stomp_url' => array(
+      '#type' => 'textfield',
+      '#title' => t('Stomp URL'),
+      '#default_value' => variable_get('islandora_stomp_url', 'tcp://localhost:61613'),
+      '#description' => t('URL to the Stomp broker for async messaging'),
+      '#element_validate' => array('islandora_config_form_validate_stomp_url'),
+      '#required' => TRUE,
+    ),
+    'islandora_triplestore_index_queue' => array(
+      '#type' => 'textfield',
+      '#title' => t('Triplestore Index Queue'),
+      '#default_value' => variable_get('islandora_triplestore_index_queue', 'islandora/triplestore/index'),
+      '#description' => t('Queue to send triplestore indexing messages'),
+      '#required' => TRUE,
+    ),
+  );
+
+  return system_settings_form($form);
+}
+
+/**
+ * Stomp broker url validator.
+ *
+ * @param array $element
+ *   Form element for stomp broker url.
+ * @param array $form_state
+ *   Drupal form state.
+ * @param array $form
+ *   Drupal renderable array.
+ */
+function islandora_config_form_validate_stomp_url(array $element, array &$form_state, array $form) {
+  // Try to connect to the server.
+  try {
+    $url = $element['#value'];
+    $stomp = new Stomp($url);
+    unset($stomp);
+  }
+  catch (StompException $e) {
+    form_error($element, t('Connection failed for @url: @message', array('@url' => $url, '@message' => $e->getMessage())));
+  }
+}
diff --git a/islandora/include/rdf.inc b/islandora/include/rdf.inc
new file mode 100644
index 00000000..d360d46b
--- /dev/null
+++ b/islandora/include/rdf.inc
@@ -0,0 +1,21 @@
+<?php
+
+/**
+ * @file
+ * Utility functions for working with RDF.
+ */
+
+/**
+ * Serializes a Drupal node to N-Triples.
+ *
+ * @param object $node
+ *   Node to serialize.
+ *
+ * @return string
+ *   RDF serialized as N-Triples.
+ */
+function islandora_serialize_node_to_triples($node) {
+  $rdf_model = rdfx_get_rdf_model('node', $node);
+  $serializer = ARC2::getSer('NTriples', array('ns' => $rdf_model->ns));
+  return $serializer->getSerializedIndex($rdf_model->index);
+}
diff --git a/islandora/include/triplestore.inc b/islandora/include/triplestore.inc
new file mode 100644
index 00000000..8a0b0605
--- /dev/null
+++ b/islandora/include/triplestore.inc
@@ -0,0 +1,70 @@
+<?php
+
+/**
+ * @file
+ * Triplestore indexing functionality.
+ */
+
+/**
+ * Enqueues a triplestore upsert action.
+ *
+ * @param object $node
+ *   Node to upsert in index.
+ *
+ * @return bool
+ *   True if publishing the message was successful.
+ */
+function islandora_triplestore_upsert($node) {
+  return islandora_triplestore_enqueue_action($node, 'upsert');
+}
+
+/**
+ * Enqueues a triplestore delete action.
+ *
+ * @param object $node
+ *   Node to delete from index.
+ *
+ * @return bool
+ *   True if publishing the message was successful.
+ */
+function islandora_triplestore_delete($node) {
+  return islandora_triplestore_enqueue_action($node, 'delete');
+}
+
+/**
+ * Enqueues a triplestore index action.
+ *
+ * @param object $node
+ *   Node to index.
+ * @param string $action
+ *   Action to take.  Either 'upsert' or 'delete' at the moment.
+ *
+ * @return bool
+ *   True if publishing the message was successful.
+ */
+function islandora_triplestore_enqueue_action($node, $action) {
+  module_load_include('inc', 'islandora', 'include/rdf');
+  $broker_url = variable_get("islandora_stomp_url", "tcp://localhost:61613");
+  $queue = variable_get("islandora_triplestore_index_queue", "islandora/triplestore/index");
+  $msg  = islandora_serialize_node_to_triples($node);
+
+  // Add enough headers to fool the FcrepoCamel code we're re-using to do this.
+  global $base_url;
+  $headers = array(
+    'action' => $action,
+    'Content-Type' => 'application/n-triples',
+    'CamelFcrepoBaseUrl' => $base_url,
+    'CamelFcrepoIdentifier' => "/node/{$node->nid}",
+  );
+
+  try {
+    $stomp = new Stomp($broker_url);
+    $stomp->send($queue, $msg, $headers);
+    unset($stomp);
+    return TRUE;
+  }
+  catch (StompException $e) {
+    watchdog('islandora', 'Error publishing triplestore index action to Stomp broker: @err', array('@err' => $e->getMessage()), WATCHDOG_ERROR);
+    return FALSE;
+  }
+}
diff --git a/islandora/include/utils.inc b/islandora/include/utils.inc
new file mode 100644
index 00000000..15743c42
--- /dev/null
+++ b/islandora/include/utils.inc
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * @file
+ * Miscellaneous utility functions for the islandora module.
+ */
+
+/**
+ * Predicate to determine if we should ignore hooks that talk to Fedora.
+ *
+ * @return bool
+ *   True if we shouldn't talk to Fedora (breaks the cycle).
+ */
+function islandora_ignore_hooks() {
+  $header_is_set = isset($_SERVER['HTTP_IGNORE_HOOKS']);
+
+  if (!$header_is_set) {
+    return FALSE;
+  }
+
+  $header_is_true = strcmp(strtolower($_SERVER['HTTP_IGNORE_HOOKS']), "true") == 0;
+
+  return $header_is_true;
+}
diff --git a/islandora/islandora.module b/islandora/islandora.module
index 9086c8aa..91bf216b 100644
--- a/islandora/islandora.module
+++ b/islandora/islandora.module
@@ -28,6 +28,24 @@ define('ISLANDORA_FEDORA_PATH_FIELD', 'field_fedora_path');
 define('ISLANDORA_FEDORA_HAS_PARENT_FIELD', 'field_fedora_has_parent');
 define('ISLANDORA_PCDM_HAS_MEMBER_FIELD', 'field_pcdm_has_member');
 
+/**
+ * Implements hook_menu().
+ */
+function islandora_menu() {
+  $items = array(
+    'admin/islandora/config' => array(
+      'title' => 'Islandora',
+      'description' => 'Configure settings for Islandora',
+      'page callback' => 'drupal_get_form',
+      'page arguments' => array('islandora_config_form'),
+      'file' => '/include/admin.form.inc',
+      'access arguments' => array('administer site configuration'),
+      'type' => MENU_NORMAL_ITEM,
+    ),
+  );
+  return $items;
+}
+
 /**
  * Implements hook_ctools_plugin_api().
  */
@@ -67,6 +85,67 @@ function islandora_entity_load($entities, $type) {
   }
 }
 
+/**
+ * Implements hook_node_postinsert().
+ */
+function islandora_node_postinsert($node) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
+    return;
+  }
+
+  $nodes = entity_uuid_load('node', array($node->uuid));
+
+  // Exit early if the node never was successfully inserted in the database.
+  if (empty($nodes)) {
+    return;
+  }
+
+  $node = array_pop($nodes);
+
+  module_load_include('inc', 'islandora', 'include/triplestore');
+  islandora_triplestore_upsert($node);
+}
+
+/**
+ * Implements hook_node_postupdate().
+ */
+function islandora_node_postupdate($node) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
+    return;
+  }
+
+  // Unfortunately, there's no way to tell if the db transaction got rolled
+  // back in this hook, so we'll default to doing it anyway so as not to miss
+  // any updates. Open to suggestions on this one.  But we gotta do post_action
+  // hooks otherwise things can get crazy if the db transaction hasn't closed.
+  $nodes = entity_uuid_load('node', array($node->uuid));
+
+  // Exit early if something has gone wrong and there's no node info.
+  if (empty($nodes)) {
+    return;
+  }
+
+  $node = array_pop($nodes);
+
+  module_load_include('inc', 'islandora', 'include/triplestore');
+  islandora_triplestore_upsert($node);
+}
+
+/**
+ * Implements hook_node_postdelete().
+ */
+function islandora_node_postdelete($node) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
+    return;
+  }
+
+  module_load_include('inc', 'islandora', 'include/triplestore');
+  islandora_triplestore_delete($node);
+}
+
 /**
  * Implements hook_default_services_endpoint().
  */
diff --git a/islandora_basic_image/islandora_basic_image.module b/islandora_basic_image/islandora_basic_image.module
index eedabf8e..196856b3 100644
--- a/islandora_basic_image/islandora_basic_image.module
+++ b/islandora_basic_image/islandora_basic_image.module
@@ -102,7 +102,8 @@ function islandora_basic_image_rdf_mapping() {
  * Implements hook_node_postinsert().
  */
 function islandora_basic_image_node_postinsert($node) {
-  if (isset($_SERVER['HTTP_IGNORE_HOOKS']) && strcmp(strtolower($_SERVER['HTTP_IGNORE_HOOKS']), "true") == 0) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
     return;
   }
 
@@ -151,7 +152,8 @@ function islandora_basic_image_node_postinsert($node) {
  * Implements hook_node_postupdate().
  */
 function islandora_basic_image_node_postupdate($node) {
-  if (isset($_SERVER['HTTP_IGNORE_HOOKS']) && strcmp(strtolower($_SERVER['HTTP_IGNORE_HOOKS']), "true") == 0) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
     return;
   }
 
@@ -194,7 +196,8 @@ function islandora_basic_image_node_postupdate($node) {
  * Implements hook_node_postdelete().
  */
 function islandora_basic_image_node_postdelete($node) {
-  if (isset($_SERVER['HTTP_IGNORE_HOOKS']) && strcmp(strtolower($_SERVER['HTTP_IGNORE_HOOKS']), "true") == 0) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
     return;
   }
 
diff --git a/islandora_collection/islandora_collection.module b/islandora_collection/islandora_collection.module
index deeb1921..eb92a651 100644
--- a/islandora_collection/islandora_collection.module
+++ b/islandora_collection/islandora_collection.module
@@ -106,7 +106,8 @@ function islandora_collection_rdf_mapping() {
  * Implements hook_node_postinsert().
  */
 function islandora_collection_node_postinsert($node) {
-  if (isset($_SERVER['HTTP_IGNORE_HOOKS']) && strcmp(strtolower($_SERVER['HTTP_IGNORE_HOOKS']), "true") == 0) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
     return;
   }
 
@@ -142,7 +143,8 @@ function islandora_collection_node_postinsert($node) {
  * Implements hook_node_postupdate().
  */
 function islandora_collection_node_postupdate($node) {
-  if (isset($_SERVER['HTTP_IGNORE_HOOKS']) && strcmp(strtolower($_SERVER['HTTP_IGNORE_HOOKS']), "true") == 0) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
     return;
   }
 
@@ -179,7 +181,8 @@ function islandora_collection_node_postupdate($node) {
  * Implements hook_node_postdelete().
  */
 function islandora_collection_node_postdelete($node) {
-  if (isset($_SERVER['HTTP_IGNORE_HOOKS']) && strcmp(strtolower($_SERVER['HTTP_IGNORE_HOOKS']), "true") == 0) {
+  module_load_include('inc', 'islandora', 'include/utils');
+  if (islandora_ignore_hooks()) {
     return;
   }