EDIT

<?php

/**

 * @file

 * CDM Node functions.

 */

define('CDM_DRUPAL_NODE_CREATION', 'cdm_drupal_node_creation');

function do_persist_drupal_nodes(){

  static $value = null;

  if($value === NULL){

    $value = variable_get(CDM_DRUPAL_NODE_CREATION, FALSE);

  }

  return $value;

}

/**

 * Implements hook_node_view().

 *

 * TODO This should also be used for other cdm node types like name page?

 */

function cdm_dataportal_node_view($node, $view_mode = 'full') {

  if($view_mode == 'search_index'){

    // this view mode is used by _node_index_node()

    // allowing drupal search to index the cdm instance

    // nodes can be a big performance problem, to this

    // viewmode is ignored

    // If you need a fearch function, use the cdm serach facilities instead.

    return;

  }

  // See cdm_add_node_content.

  switch ($node->type) {

    case 'cdm_' . NODETYPE_TAXON:

    case 'cdm_' . NODETYPE_SPECIMEN:

    case 'cdm_' . NODETYPE_NAME:

    case 'cdm_' . NODETYPE_REFERENCE:

    case 'cdm_' . NODETYPE_MEDIA:

      if (!isset($node->cdm) && arg(0) == 'node') {

        // If a node page is loaded directly, e.g. node/%nid instead of

        // cdm_dataportal/taxon/%uuid, try to load the taxon page content

        // into $node->cdm.

        // only do this for node pages (where arg(0) = node),

        // not for pages like comment/reply/%nid.

        $cdmnode = db_query('SELECT uuid FROM {node_cdm} WHERE nid = :nid', array(

          ':nid' => $node->nid,

        ))->fetch();

        if (isset($cdmnode->uuid)) {

          cdm_dataportal_taxon_page_view($cdmnode->uuid);

        }

      }

      $node->content['cdm'] = isset($node->cdm) ? $node->cdm : '';

      break;

  }

}

/**

 * Implements hook_node_delete().

 */

function cdm_dataportal_node_delete($node) {

  if (array_key_exists($node->type, cdm_get_nodetypes())) {

    db_delete('node_cdm')->condition('nid', $node->nid)->execute();

  }

}

/**

 * Loads the node if one exist for $uuid, or else creates one.

 *

 * @param string $nodetype

 *   The node type.

 * @param string $uuid

 *   UUID for which to load the node.

 * @param string $title

 *   The node title to display for the node.

 *

 * @return mixed

 *   The node object for $uuid.

 */

function cdm_load_node($nodetype, $uuid, $title) {

  // Try to find node id.

  $cdmnode = db_query('SELECT nid, cdmtype FROM {node_cdm} WHERE wsuri = :wsuri AND cdmtype = :cdmtype AND uuid = :uuid', array(

    ':wsuri' => variable_get('cdm_webservice_url', NULL),

    ':cdmtype' => $nodetype,

    ':uuid' => $uuid,

  ))->fetch();

  // Nid should not be 0 , if it is, something is wrong with the record.

  if (isset($cdmnode->nid) && $cdmnode->nid == 0) {

    drupal_set_message(t('Something is wrong with the record for uuid=%uuid,

      please contact the helpdesk.', array('%uuid' => $uuid)), 'error');

    return;

  }

  if (isset($cdmnode->nid) && is_numeric($cdmnode->nid)) {

    $node = node_load($cdmnode->nid);

  }

  else {

    // Create a new node.

    $node = new stdClass();

    $node->type = 'cdm_' . $nodetype;

    // Comment @WA TODO set to e.g. 'en' if locale is enabled.

    $node->language = LANGUAGE_NONE;

    // Set some default values for:

    // 'status', 'promote', 'sticky', 'uid' and 'created'.

    node_object_prepare($node);

    // Use just the plain text of the HTML title.

    $title = filter_xss($title, array());

    // Limit length to the max length of the database field 128.

    $title = substr($title, 0, 128);

    $node->title = $title;

    if(do_persist_drupal_nodes()){

      // using the system admin user for all new nodes

      $node->uid = 0;

      // 2 = comments on, 1 = comments off.

      $node->comment = variable_get('comment_' . $node->type);

      // Preserve the current messages but before saving the node.

      $messages = drupal_set_message();

      if ($node = node_submit($node)) {

        // Prepare node for saving by populating author and creation date.

        // Comment @WA: Note that node_save is using a helper function to save a

        // revision with the uid of the current user so the revision will not

        // have uid = 0 but the uid of the current user.

        // I guess that is not a problem so I leave it like this. Remedy would be

        // to alter that revision entry afterwards.

        // Will create a watchdog log entry if it fails to create the node.

        node_save($node);

      }

      // Restore the messages.

      $_SESSION['messages'] = $messages;

      // Comment @WA: I think http://dev.e-taxonomy.eu/trac/ticket/2964 is not

      // relevant here anymore, since node_save will roll_back if node cannot be

      // created.

      if (!isset($node->nid)) {

        $message = t('Could not create node for !nodetype (!title).', array(

          '!nodetype' => $nodetype,

          '!title' => $title,

        ));

        drupal_set_message($message, 'error');

        watchdog('content', '@message', array('@message' => $message), WATCHDOG_ERROR);

        return NULL;

      }

      // Hash as a 32-character hexadecimal number.

      $hash = md5(variable_get('cdm_webservice_url') . $uuid);

      $id = db_insert('node_cdm')->fields(array(

        'nid' => $node->nid,

        'wsuri' => variable_get('cdm_webservice_url'),

        'hash' => $hash,

        'cdmtype' => $nodetype,

        'uuid' => $uuid,

      ))->execute();

    } else {

      // Drupal node is not persisted

      // need to create fake nid

      $node->nid = 0;

    }

  }

  return $node;

}

/**

 * Wrapper function around node_show()

 *

 * Just like the drupal function node_show() this function will generate an

 * array which displays a node detail page. Prior calling node_show() this

 * function assures that the special cdm node types are undegone the nessecary

 * preprocessing.

 *

 * This function will be called by a cdm_dataportal_{CDM_NODE_TYPE}_view function.

 *

 *

 * @param String $cdm_node_type

 *     one of the cdm content type names as defined in

 *     the file node_types.php. Possible values are 'taxon', 'media', 'reference', 'name'.

 *     you may want to use the according contstants instred of the string: NODETYPE_TAXON,

 *     NODETYPE_MEDIA, NODETYPE_REFERENCE, NODETYPE_NAME.

 * @param String $uuid

 *     the UUID string of the cdm entitiy to be shown. The cdm type is of cource defined by

 *     the  $cdm_node_type value

 * @param String $title

 *     the Page title

 * @param String or render array? $content

 *

 * @return

 *     A $page element suitable for use by drupal_render().

 */

function cdm_node_show($cdm_node_type, $uuid, $title, $content) {

  if(!user_access('access cdm content')){

    drupal_access_denied();

  }

  // tell drupal code to load the node

  $node = cdm_load_node($cdm_node_type, $uuid, $title);

  // set the title coming supplied by a cdm_dataportal_{CDM_NODE_TYPE}_view function

  drupal_set_title($title, PASS_THROUGH);

  cdm_add_node_content($node, $content);

  if(do_persist_drupal_nodes()){

    // use the full node_show()

    $nodes = node_show($node);

  } else {

    // only use a part of the methods called in the node_show() method

    $nodes = node_view_multiple(array($node->nid => $node), 'full');

  }

  return $nodes;

}

/**

 * Simulates the influence on the page layout by cdm_node_show().

 *

 * Adds a div as first element for the general part, which usually is empty in dataporal pages.

 *

 * @param $content

 */

function cdm_node_show_simulate($content)

{

  $general_div = "<div id=\"general\" class=\"page-part\"></div>";

  if(is_array($content)){

    array_unshift($content, array("general-part" => markup_to_render_array($general_div)));

    return drupal_render($content);

  } else {

    return $general_div . $content;

  }

}

/**

 * Sets the $content given a paramater to the $node object

 *

 * The $content can either be a string or an array.

 *

 * see:

 *  - element_children()

 *  - drupal_render()

 *  - http://api.drupal.org/api/drupal/includes!common.inc/function/drupal_render/7#comment-6644

 *

 * TODO see notes near bottom of function

 *

 * @param object $node

 *   A $node object

 * @param string|array $content

 *   The content to set for the $node

 *

 */

function cdm_add_node_content(&$node, $content) {

  if(is_array($content)) {

    // $content seems to be a render array suitable for drupal_render()

    $cdm_content = array(

        // Wrap content in cdm_dataportal specific container.

        '#prefix' => '<div id="cdm_dataportal.node">',

        '#suffix' => '</div>',

        // the key of child elements can be chosen arbitrarily it only must not start with a '#'

        'content' => $content,

        '#weight' => variable_get('cdm_content_weight', -1),

    );

  } else {

    // Wrap content in cdm_dataportal specific container.

    $cdm_content = markup_to_render_array( $content, variable_get('cdm_content_weight', -1));

  }

  //  $node->content is cleared in node_build_content() therefore we need to

  //  implement the 'view' hook in order to set the  $node->content

  //  properly => cdm_dataportal_node_view()

  $node->cdm = $cdm_content;

}

/**

 * Deletes all cdm nodes, used when module is uninstalled

 */

function cdm_delete_all_cdm_nodes() {

  $result = db_query('SELECT n.nid FROM {node} n WHERE n.type like :type', array(':type' => 'cdm_%'));

  foreach ($result as $node) {

    node_delete($node->nid);

  }

}