node.module

<?php
// $Id$

function node_help($section = "admin/help#node") {
  global $mod;
  $output = "";

  switch ($section) {

    case 'admin/help#node':
      $output .= "<h3>Nodes</h3>";
      $output .= "<p>The core of the Drupal system is the node. All of the contents of the system are placed in nodes, or extensions of nodes.";
      $output .= "A base node contains:<dl>";
      $output .= "<dt>A Title</dt><dd>Up to 128 characters of text that titles the node.</dd>";
      $output .= "<dt>A Teaser</dt><dd>A small block of text that is meant to get you interested in the rest of node. Drupal will automatically pull a small amount of the body of the node to make the teaser (To configure how long the teaser will be %teaser). The teaser can be changed if you don't like what Drupal grabs.</dd>";
      $output .= "<dt>The Body</dt><dd>The main text that comprises your content.</dd>";
      $output .= "<dt>A Type</dt><dd>What kind of node is this? Blog, book, forum, comment, unextended, etc.</dd>";
      $output .= "<dt>An Author</dt><dd>The author's name. It will either be \"anonymous\" or a valid user. You <i>cannot</i> set it to an arbitrary value.</dd>";
      $output .= "<dt>Authored on</dt><dd>The date the node was written.</dd>";
      $output .= "<dt>Changed</dt><dd>The last time this node was changed.</dd>";
      $output .= "<dt>Static on front page</dt><dd>The front page is configured to show the teasers from only a few of the total nodes you have on your site (To configure how many teasers %teaser), but if you think a node is important enough that you want it to stay on the front page enable this.</dd>";
      $output .= "<dt>Allow user comments</dt><dd>A node can have comments. These comments can be written by other users (Read-write), or only by admins (Read-only).</dd>";
      $output .= "<dt>Attributes</dt><dd>A way to sort nodes.</dd>";
      $output .= "<dt>Revisions</dt><dd>Drupal has a revision system so that you can \"roll back\" to an older version of a post if the new version is not what you want.</dd>";
      $output .= "<dt>Promote to front page</dt><dd>To get people to look at the new stuff on your site you can choose to move it to the front page.</dd>";
      $output .= "<dt>In moderation queue</dt><dd>Drupal has a moderation system. If it is active, a node is in one of three states: approved and published, approved and unpublished, and awaiting approval. If you are moderating a node it should be in the moderation queue.</dd>";
      $output .= "<dt>Votes</dt><dd>If you are moderating a node this counts how many votes the node has gotten. Once a node gets a certain number of vote if will either be approved or dropped.";
      $output .= "<dt>Score</dt><dd>The score of the node is gotten by the votes it is given.</dd>";
      $output .= "<dt>Users</dt><dd>The list of users who have voted on a moderated node.</dd>";
      $output .= "<dt>Published</dt><dd>When using Drupal's moderation system a node remains unpublished -- unavaliable to non-moderators -- until it is marked Published.</dd></dl>";
      $output .= "<p>Now that you know what is in a node, here are some of the types of nodes available.</p>";

      $output = t($output, array("%teaser" => l(t("click here"), "admin/system/modules/node")));

      if ($mod == "admin") {
        foreach (module_list() as $name) {
          if (module_hook($name, "node") && $name != "node") {
            $output .= "<h3>". t("Node type: %module", array("%module" => module_invoke($name, "node", "name"))) ."</h3>";
            $output .= module_invoke($name, "node", "description");
          }
        }
      }
      break;

    case 'admin/system/modules#description':
      $output = t("The core that allows content to be submitted to the site.");
      break;
    case 'admin/system/modules/node':
      $output = t("Settings for the core of Drupal. Almost everything is a node so these settings will affect most of the site.");
      break;
    case 'admin/node':
      $output = t("Below is a list of all of the nodes in your site. Other forms of content are listed elsewhere (e.g. %comments).<br />Clicking a title views that node, while clicking an author's name edits their user information.<br />Other node-related tasks are available from the menu on the left.", array("%comments" => l(t("comments"), "admin/comment")));
      break;
    case 'admin/node/search':
      $output = t("Enter a simple pattern to search for a post. This can include the wildcard character *.<br />For example, a search for \"br*\" might return \"bread bakers\", \"our daily bread\" and \"brenda\".");
      break;
    case 'admin/node/settings':
      $output = t("This page lets you set the defaults used during creation of nodes for all the different node types.<br /><strong>comment:</strong> Read/write setting for comments.<br /><strong>publish:</strong> Is this node publicly viewable, has it been published?<br /><strong>promote:</strong> Is this node to be promoted to the front page?<br /><strong>moderate:</strong> Does this node need approval before it can be viewed?<br /><strong>static:</strong> Is this node always visible on the front page?<br /><strong>revision:</strong> Will this node go into the revision system allowing multiple versions to be saved?");
      break;

  }

  return $output;
}

function node_help_page() {
  print theme("page", node_help());
}


/*
** Accepts a DB result object which can be used to fetch node objects.
** Returns an HTML list suitable as content for a block.
*/
function node_title_list($result, $title = NULL) {
  while ($node = db_fetch_object($result)) {
    $number = module_invoke("comment", "num_all", $node->nid);
    $items[] = l($node->title, "node/view/$node->nid", array("title" => format_plural($number, "%count comment", "%count comments")));
  }

  return theme("node_list", $items, $title);
}

function theme_node_list($items, $title = NULL) {
  return theme("item_list", $items, $title);
}

// Update the 'last viewed' timestamp of the specified node for current user.
function node_tag_new($nid) {
  global $user;

  if ($user->uid) {
    $result = db_query("SELECT timestamp FROM {history} WHERE uid = %d AND nid = %d", $user->uid, $nid);
    if (db_fetch_object($result)) {
      db_query("UPDATE {history} SET timestamp = %d WHERE uid = %d AND nid = %d", time(), $user->uid, $nid);
    }
    else {
      db_query("INSERT INTO {history} (uid, nid, timestamp) VALUES (%d, %d, %d)", $user->uid, $nid, time());
    }
  }
}

/*
** Retrieves the timestamp at which the current user last viewed the
** specified node.
*/
function node_last_viewed($nid) {
  global $user;

  $history = db_fetch_object(db_query("SELECT timestamp FROM {history} WHERE uid = '$user->uid' AND nid = %d", $nid));
  return ($history->timestamp ? $history->timestamp : 0);
}

/**
 * Determines whether the supplied timestamp is newer than the user's last view
 * of a given node
 *
 * @param $nid node-id twhose history supplies the 'last viewed' timestamp
 * @param $timestamp time which is compared against node's 'last veiwed'
 *   timestamp
 */
function node_is_new($nid, $timestamp) {
  global $user;
  static $cache;

  if (!isset($cache[$nid])) {
    if ($user->uid) {
      $history = db_fetch_object(db_query("SELECT timestamp FROM {history} WHERE uid = %d AND nid = %d", $user->uid, $nid));
      $cache[$nid] = $history->timestamp ? $history->timestamp : 0;
    }
    else {
      $cache[$nid] = time();
    }
  }

  if ($timestamp > $cache[$nid]) {
    return 1;
  }
  else {
    return 0;
  }
}

function node_teaser($body) {

  $size = variable_get("teaser_length", 600);

  /*
  ** If the size is zero, teasers are disabled so we
  ** return the entire body.
  */

  if ($size == 0) {
    return $body;
  }

  /*
  ** If a valid delimiter has been specified, use it to
  ** chop of the teaser.  The delimiter can be outside
  ** the allowed range but no more than a factor two.
  */

  $delimiter = strpos($body, "<!--break-->");
  if ($delimiter > 0) {
    return substr($body, 0, $delimiter);
  }

  /*
  ** If we have a short body, return the entire body:
  */

  if (strlen($body) < $size) {
    return $body;
  }

  /*
  ** In some cases no delimiter has been specified (eg.
  ** when posting using the Blogger API) in which case
  ** we try to split at paragraph boundaries.
  */

  if ($length = strpos($body, "</p>", $size)) {
    return substr($body, 0, $length + 4);
  }

  if ($length = strpos($body, "<br />", $size)) {
    return substr($body, 0, $length);
  }

  if ($length = strpos($body, "<br>", $size)) {
    return substr($body, 0, $length);
  }

  if ($length = strpos($body, "\n", $size)) {
    return substr($body, 0, $length);
  }

  /*
  ** When even the first paragraph is too long, try to
  ** split at the end of the next sentence.
  */

  if ($length = strpos($body, ". ", $size)) {
    return substr($body, 0, $length + 1);
  }

  if ($length = strpos($body, "! ", $size)) {
    return substr($body, 0, $length + 1);
  }

  if ($length = strpos($body, "? ", $size)) {
    return substr($body, 0, $length + 1);
  }

  /*
  ** Nevermind, we split it the hard way ...
  */

  return substr($body, 0, $size);
}

function node_invoke(&$node, $hook, $a2 = NULL, $a3 = NULL, $a4 = NULL) {
  if (is_array($node)) {
    $function = $node["type"] ."_$hook";
  }
  else if (is_object($node)) {
    $function = $node->type ."_$hook";
  }
  else if (is_string($node)) {
    $function = $node ."_$hook";
  }

  if (function_exists($function)) {
    return ($function($node, $a2, $a3, $a4));
  }
}

function node_invoke_nodeapi(&$node, $op, $arg = 0) {
  $return = array();
  foreach (module_list() as $name) {
    $function = $name ."_nodeapi";
    if (function_exists($function)) {
      $result = $function($node, $op, $arg);
      if (isset($result)) {
        $return = array_merge($return, $result);
      }
    }
  }
  return $return;
}

function node_load($conditions, $revision = -1) {

  /*
  ** Turn the conditions into a query:
  */

  foreach ($conditions as $key => $value) {
    $cond[] = "n.". check_query($key) ." = '". check_query($value) ."'";
  }

  /*
  ** Retrieve the node:
  */

  $node = db_fetch_object(db_query("SELECT n.*, u.uid, u.name FROM {node} n INNER JOIN {users} u ON u.uid = n.uid WHERE ". implode(" AND ", $cond)));

  /*
  ** Unserialize the revisions field:
  */

  if ($node->revisions) {
    $node->revisions = unserialize($node->revisions);
  }

  /*
  ** Call the node specific callback (if any) and piggy-back the
  ** results to the node or overwrite some values:
  */

  if ($extra = node_invoke($node, "load")) {
    foreach ($extra as $key => $value) {
      $node->$key = $value;
    }
  }

  /*
  ** Return the desired revision
  */
  if ($revision != -1 && isset($node->revisions[$revision])) {
    $node = $node->revisions[$revision]["node"];
  }

  return $node;
}

function node_save($node) {

  /*
  ** Fetch fields to save to node table:
  */
  $fields = node_invoke_nodeapi($node, "fields");

  /*
  ** Serialize the revisions field:
  */

  if ($node->revisions) {
    $node->revisions = serialize($node->revisions);
  }

  /*
  ** Apply filters to some default node fields:
  */

  if (empty($node->nid)) {

    /*
    ** Insert a new node:
    */

    // Set some required fields:
    if (!$node->created) {
      $node->created = time();
    }
    $node->changed = time();
    $node->nid = db_next_id("{node}_nid");

    // Prepare the query:
    foreach ($node as $key => $value) {
      if (in_array($key, $fields)) {
        $k[] = check_query($key);
        $v[] = $value;
        $s[] = "'%s'";
      }
    }

    $keysfmt = implode(", ", $s);
    // need to quote the placeholders for the values
    $valsfmt = "'". implode("', '", $s) ."'";

    // Insert the node into the database:
    db_query("INSERT INTO {node} (". implode(", ", $k) .") VALUES(". implode(", ", $s) .")", $v);

    // Call the node specific callback (if any):
    node_invoke($node, "insert");
    node_invoke_nodeapi($node, "insert");
  }
  else {

    /*
    ** Update an existing node:
    */

    // Set some required fields:
    $node->changed = time();

    // Prepare the query:
    foreach ($node as $key => $value) {
      if (in_array($key, $fields)) {
        $q[] = check_query($key) ." = '%s'";
        $v[] = $value;
      }
    }

    // Update the node in the database:
    db_query("UPDATE {node} SET ". implode(", ", $q) ." WHERE nid = '$node->nid'", $v);

    // Call the node specific callback (if any):
    node_invoke($node, "update");
    node_invoke_nodeapi($node, "update");
  }

  /*
  ** Clear the cache so an anonymous poster can see the node being
  ** added or updated.
  */

  cache_clear_all();

  /*
  ** Return the node ID:
  */

  return $node->nid;

}

function node_view($node, $main = 0, $page = 0) {

  $node = array2object($node);

  /*
  ** Remove the delimiter (if any) that seperates the teaser from the
  ** body. TODO: this strips legitimate uses of '<!--break-->' also.
  */

  $node->body = str_replace("<!--break-->", "", $node->body);

  /*
  ** The "view" hook can be implemented to overwrite the default function
  ** to display nodes.
  */

  if (module_hook($node->type, "view")) {
    return node_invoke($node, "view", $main, $page);
  }
  else {

    /*
    ** Default behavior:
    */

    if ($node->teaser == $node->body) {
      // Only invoke check_output() once for performance's sake:
      $node->teaser = $node->body = check_output($node->teaser);
    }
    else {
      $node->teaser = check_output($node->teaser);
      $node->body = check_output($node->body);
    }

    return theme("node", $node, $main, $page);
  }
}

function node_show($node, $cid) {

  if (node_access("view", $node)) {

    $output = node_view($node, 0, 1);

    if (function_exists("comment_render") && $node->comment) {
      $output .= comment_render($node, $cid);
    }

    /*
    ** Update the history table, stating that this user viewed this node.
    */

    node_tag_new($node->nid);

    return $output;
  }
  else {
    drupal_set_message(message_access());
  }
}

function node_access($op, $node = 0) {

  if (user_access("administer nodes")) {
    return 1;
  }

  /*
  ** Convert the node to an object if necessary:
  */

  $node = array2object($node);

  /*
  ** Construct a function:
  */

  if ($node->type) {
    $type = $node->type;
  }
  else {
    $type = $node;
  }

  // Can't use node_invoke:
  // the access hook takes the $op parameter before the $node parameter.
  return module_invoke($type, "access", $op, $node);
}

function node_perm() {
  return array("administer nodes", "access content");
}

function node_search($keys) {

  // Return the results of performing a search using the indexed search
  // for this particular type of node.
  //
  // Pass an array to the "do_search" function which dictates what it
  // will search through, and what it will search for
  //
  // "keys"'s value is the keywords entered by the user
  //
  // "type"'s value is used to identify the node type in the search
  // index.
  //
  // "select"'s value is used to relate the data from the specific nodes
  // table to the data that the search_index table has in it, and the the
  // do_search functino will rank it.
  //
  // The select must always provide the following fields - lno, title,
  // created, uid, name, count
  //
  $find = do_search(array("keys" => $keys, "type" => "node", "select" => "select s.lno as lno, n.title as title, n.created as created, u.uid as uid, u.name as name, s.count as count FROM {search_index} s, {node} n INNER JOIN {users} u ON n.uid = u.uid WHERE s.lno = n.nid AND s.type = 'node' AND s.word like '%' AND n.status = 1"));

  return $find;
}

function node_settings() {
  $output .= form_select(t("Number of posts on main page"), "default_nodes_main", variable_get("default_nodes_main", 10), array(1 => 1, 2 => 2, 3 => 3, 4 => 4, 5 =>  5, 6 => 6, 7 => 7, 8 => 8, 9 => 9, 10 => 10, 15 => 15, 20 => 20, 25 => 25, 30 => 30), t("The default maximum number of posts to display per page on overview pages such as the main page."));
  $output .= form_select(t("Length of trimmed posts"), "teaser_length", variable_get("teaser_length", 600), array(0 => t("Unlimited"), 200 => t("200 characters"), 400 => t("400 characters"), 600 => t("600 characters"), 800 => t("800 characters"), 1000 => t("1000 characters"), 1200 => t("1200 characters"), 1400 => t("1400 characters"), 1600 => t("1600 characters"), 1800 => t("1800 characters"), 2000 => t("2000 characters")), t("The maximum number of characters used in the trimmed version of a post.  Drupal will use this setting to determine at which offset long posts should be trimmed.  The trimmed version of a post is typically used as a teaser when displaying the post on the main page, in XML feeds, etc.  To disable teasers, set to 'Unlimited'."));
  $output .= form_radios(t("Preview post"), "node_preview", variable_get("node_preview", 0), array(t("Optional"), t("Required")), t("Must users preview posts before submitting?"));

  return $output;
}

function node_conf_filters() {
  $group1 .= form_radios(t("Filter HTML tags"), "filter_html", variable_get("filter_html", 0), array(0 => t("Do not filter"), 1 => t("Strip tags"), 2 => t("Escape tags")), t("How to deal with HTML and PHP tags in user-contributed content. If set to \"Strip tags\", dangerous tags are removed (see below).  If set to \"Escape tags\", all HTML is escaped and presented as it was typed."));
  $group1 .= form_textfield(t("Allowed HTML tags"), "allowed_html", variable_get("allowed_html", "<a> <b> <dd> <dl> <dt> <i> <li> <ol> <u> <ul>"), 64, 255, t("If \"Strip tags\" is selected, optionally specify tags which should not be stripped.  'ON*' attributes and unclosed tags are always stripped."));
  $group1 .= form_radios(t("HTML style attributes"), "filter_style", variable_get("filter_style", 1), array(t("Allowed"), t("Removed")), t("If \"Strip tags\" is selected, you can choose whether 'STYLE' attributes are allowed or removed from input."));
  $output .= form_group("HTML filtering", $group1);

  $group2 .= form_radios(t("Rewrite old URLs"), "rewrite_old_urls", variable_get("rewrite_old_urls", 0), array(t("Disabled"), t("Enabled")), t("The introduction of 'clean URLs' in Drupal 4.2.0 breaks internal URLs that date back from Drupal 4.1.0 and before.  If enabled, this filter will attempt to rewrite the old style URLs to avoid broken links.  If <code>mod_rewrite</code> is available on your system, use the rewrite rules in Drupal's <code>.htaccess</code> file instead as these will also correct external referrers."));
  $output .= form_group("Legacy filtering", $group2);

  return $output;
}

function node_escape_html($text) {
  return htmlspecialchars($text);
}

function node_filter_html($text) {
  $text = strip_tags($text, variable_get("allowed_html", ""));

  if (variable_get("filter_style", 1)) {
    $text = preg_replace("/\Wstyle\s*=[^>]+?>/i", ">", $text);
  }

  $text = preg_replace("/\Won[a-z]+\s*=[^>]+?>/i", ">", $text);

  return $text;
}

function node_filter_link($text) {
  $pat = '\[{2}([^\|]+)(\|([^\|]+)?)?\]{2}';                   // [link|description]
  return ereg_replace($pat, $dst, $text);
}

function node_comment_mode($nid) {
  static $comment_mode;
  if (!isset($comment_mode[$nid])) {
    $comment_mode[$nid] = db_result(db_query("SELECT comment FROM {node} WHERE nid = %d", $nid));
  }
  return $comment_mode[$nid];
}

function node_filter($text) {
  if (variable_get("filter_html", 0) == 1) {
    $text = node_filter_html($text);
  }

  if (variable_get("rewrite_old_urls", 0)) {
    $text = rewrite_old_urls($text);
  }

  if (variable_get("filter_html", 0) == 2) {
    $text = node_escape_html($text);
  }

  return trim($text);
}

function node_link($type, $node = 0, $main = 0) {

  $links = array();

  if ($type == "node") {
    if ($node->links) {
      $links = $node->links;
    }

    if ($main == 1 && $node->teaser && strlen($node->teaser) != strlen($node->body)) {
      $links[] = l(t("read more"), "node/view/$node->nid", array("title" => t("Read the rest of this posting."), "class" => "read-more"));
    }

    if (user_access("administer nodes")) {
      $links[] = l(t("administer"), "admin/node/edit/$node->nid", array("title" => t("Administer this node.")));
    }

    if (user_access("administer nodes") && $node->revisions) {
      $links[] = l(t("revisions"), "node/revisions/$node->nid", array("title" => t("Administer revisions.")));
    }
  }

  if ($type == "system") {
    menu("node/add", t("create content"), 'node_page', 1, MENU_HIDE_NOCHILD);

    if (user_access("administer nodes")) {
      menu("admin/node", t("content"), "node_admin");
      menu("admin/node/search", t("search"), "node_admin", 8);
      menu("admin/node/help", t("help"), "node_help_page", 9);
      menu("admin/node/edit", t("edit post"), "node_admin", 0, MENU_HIDE);
      menu("admin/node/settings", t("settings"), "node_admin", 8);
    }

    if (user_access("access content")) {
      menu("node", t("content"), "node_page", 0, MENU_HIDE);
    }
  }

  return $links;
}

function node_admin_edit($node) {

  if (is_numeric($node)) {
    $node = node_load(array("nid" => $node));
  }

  $output .= node_form($node);

  /*
  ** Display the node form extensions:
  */
  $output .= implode("\n", module_invoke_all("node_link", $node));

  return $output;

}

function node_admin_nodes() {
  $filters = array(
    array(t("View posts that are new or updated"), "ORDER BY n.changed DESC"),
    array(t("View posts that need approval"), "WHERE n.status = 0 OR n.moderate = 1 ORDER BY n.changed DESC"),
    array(t("View posts that are promoted"), "WHERE n.status = 1 AND n.promote = 1 ORDER BY n.changed DESC"),
    array(t("View posts that are not promoted"), "WHERE n.status = 1 AND n.promote = 0 ORDER BY n.changed DESC"),
    array(t("View posts that are static"), "WHERE n.status = 1 AND n.static = 1 ORDER BY n.changed DESC"),
    array(t("View posts that are unpublished"), "WHERE n.status = 0 AND n.moderate = 0 ORDER BY n.changed DESC")
   );

  $operations = array(
    array(t("Approve the selected posts"), "UPDATE {node} SET status = 1, moderate = 0 WHERE nid = %d"),
    array(t("Promote the selected posts"), "UPDATE {node} SET status = 1, promote = 1 WHERE nid = %d"),
    array(t("Make the selected posts static"), "UPDATE {node} SET status = 1, static = 1 WHERE nid = %d"),
    array(t("Demote the selected posts"), "UPDATE {node} SET promote = 0 WHERE nid = %d"),
    array(t("Unpublish the selected posts"), "UPDATE {node} SET status = 0 WHERE nid = %d")
  );

  /*
  ** Handle operations:
  */

  if (empty($_SESSION["node_overview_filter"])) {
    $_SESSION["node_overview_filter"] = 0;
  }

  if (isset($_POST["edit"]["filter"])) {
    $_SESSION["node_overview_filter"] = $_POST["edit"]["filter"];
  }

  if (isset($_POST["edit"]["operation"])) {
    $operation = $operations[$_POST["edit"]["operation"]][1];
    foreach ($_POST["edit"]["status"] as $nid => $value) {
      if ($value) {
        db_query($operation, $nid);
      }
    }

    drupal_set_message(t("the update has been performed."));
  }

  $filter = $_SESSION["node_overview_filter"];

  /*
  ** Render filter form:
  */

  $options = array();
  foreach ($filters as $key => $value) {
    $options[] = $value[0];
  }

  $form  = form_select(NULL, "filter", $filter, $options);
  $form .= form_submit(t("Go"));

  $output .= "<h3>". t("Filter options") ."</h3>";
  $output .= "<div class=\"container-inline\">$form</div>";

  /*
  ** Render operations form:
  */

  $options = array();
  foreach ($operations as $key => $value) {
    $options[] = $value[0];
  }

  $form = form_select(NULL, "operation", 0, $options);
  $form .= form_submit(t("Go"));

  $output .= "<h3>". t("Update options") ."</h3>";
  $output .= "<div class=\"container-inline\">$form</div>";

  /*
  ** Overview table:
  */

  $result = pager_query("SELECT n.*, u.name, u.uid FROM {node} n INNER JOIN {users} u ON n.uid = u.uid ". $filters[$filter][1], 50);
  $header = array(NULL, t("title"), t("type"), t("author"), t("status"), array("data" => t("operations"), "colspan" => 2));

  while ($node = db_fetch_object($result)) {
    $rows[] = array(form_checkbox(NULL, "status][$node->nid", 1, 0), l($node->title, "node/view/$node->nid") ." ". (node_is_new($node->nid, $node->changed) ? theme_mark() : ""), module_invoke($node->type, "node", "name"), format_name($node), ($node->status ? t("published") : t("not published")), l(t("edit node"), "admin/node/edit/$node->nid"), l(t("delete node"), "admin/node/delete/$node->nid"));
  }

  if ($pager = theme("pager", NULL, 50, 0)) {
    $rows[] = array(array("data" => $pager, "colspan" => 7));
  }

  $output .= "<h3>". $filters[$filter][0] ."</h3>";
  $output .= theme("table", $header, $rows);
  return form($output);
}

function node_admin_settings($edit) {
  $op = $_POST["op"];

  if ($op == t("Save configuration")) {
    /*
    ** Save the configuration options:
    */

    foreach ($edit as $name => $value) {
      variable_set($name, $value);
    }
    drupal_set_message(t("the content settings have been saved."));
  }

  if ($op == t("Reset to defaults")) {
    /*
    ** Reset the configuration options to their default value:
    */

    foreach ($edit as $name => $value) {
      variable_del($name);
    }
    drupal_set_message(t("the content settings have been reset to their default values."));
  }

  $header = array_merge(array(t("type")), array_keys(node_invoke_nodeapi($node, "settings")));
  foreach (module_list() as $name) {
    if (module_hook($name, "node")) {
      $node->type = $name;
      $cols = array();
      foreach (node_invoke_nodeapi($node, "settings") as $setting) {
        $cols[] = array("data" => $setting, "align" => "center", "width" => 55);
      }
      $rows[] = array_merge(array(module_invoke($name, "node", "name")), $cols);
    }
  }

  $output .= theme("table", $header, $rows);

  /* This is an idea for the future.
  foreach (module_list() as $name) {
    if (module_hook($name, "node")) {
      $node->type = $name;

      // Create theme("table", ) data:
      $header = array_keys(node_invoke_nodeapi($node, "settings"));
      $cols = array();
      foreach (node_invoke_nodeapi($node, "settings") as $setting) {
        $cols[] = array("data" => $setting, "align" => "center", "width" => 75);
      }

      $output .= "<h2>". module_invoke($name, "node", "name") ."</h2>";
      $output .= theme("table", $header, array($cols));
      $output .= "<br /><br />";
    }
  }
  */

  $output .= form_submit(t("Save configuration"));
  $output .= form_submit(t("Reset to defaults"));

  return form($output);

}

function node_revision_overview($nid) {

  if (user_access("administer nodes")) {
    $node = node_load(array("nid" => $nid));

    if ($node->revisions) {
      $header = array(t("older revisions"), array("colspan" => "3", "data" => t("operations")));

      foreach ($node->revisions as $key => $revision) {
        $rows[] = array(t("revision #%r revised by %u on %d", array("%r" => $key, "%u" => format_name(user_load(array("uid" => $revision["uid"]))), "%d" => format_date($revision["timestamp"], "small"))) . ($revision["history"] ? "<br /><small>". $revision["history"] ."</small>" : ""), l(t("view"), "node/view/$node->nid", array(), "revision=$key"), l(t("rollback"), "node/rollback-revision/$node->nid/$key"), l(t("delete"), "node/delete-revision/$node->nid/$key"));
      }
      $output .= theme("table", $header, $rows);
    }
  }

  return $output;
}


/*
** Return the revision with the specified revision number.
*/

function node_revision_load($node, $revision) {
  return $node->revisions[$revision]["node"];
}

/*
** Create and return a new revision of the given node.
*/

function node_revision_create($node) {
  global $user;

  /*
  ** 'revision' is the name of the field used to indicicate that we
  ** have to create a new revision of a node.
  */

  if ($node->nid && $node->revision) {
    $prev = node_load(array("nid" => $node->nid));
    $node->revisions = $prev->revisions;
    unset($prev->revisions);
    $node->revisions[] = array("uid" => $user->uid, "timestamp" => time(), "node" => $prev, "history" => $node->history);
  }

  return $node;
}

/*
** Roll-back to the revision with the specified revision number.
*/

function node_revision_rollback($nid, $revision) {
  global $user;

  if (user_access("administer nodes")) {
    $node = node_load(array("nid" => $nid));

    /*
    ** Extract the specified revision:
    */

    $rev = $node->revisions[$revision]["node"];

    /*
    ** Inherit all the past revisions:
    */

    $rev->revisions = $node->revisions;

    /*
    ** Save the original/current node:
    */

    $rev->revisions[] = array("uid" => $user->uid, "timestamp" => time(), "node" => $node);

    /*
    ** Remove the specified revision:
    */

    unset($rev->revisions[$revision]);

    /*
    ** Save the node:
    */

    foreach ($node as $key => $value) {
      $filter[] = $key;
    }

    node_save($rev, $filter);

    drupal_set_message(t("rollbacked to revision #%revision of '%title'", array("%revision" => $revision, "%title" => $node->title)));
  }
}

/*
** Delete the revision with specified revision number.
*/

function node_revision_delete($nid, $revision) {

  if (user_access("administer nodes")) {
    $node = node_load(array("nid" => $nid));

    unset($node->revisions[$revision]);

    node_save($node, array("nid", "revisions"));

    drupal_set_message(t("deleted revision #%revision of '%title'", array("%revision" => $revision, "%title" => $node->title)));
  }
}

/*
** Return a list of all the existing revision numbers.
*/

function node_revision_list($node) {
  if (is_array($node->revisions)) {
    return array_keys($node->revisions);
  }
  else {
    return array();
  }
}

function node_admin() {
  $op = $_POST["op"];
  $edit = $_POST["edit"];

  if (user_access("administer nodes")) {

    if (empty($op)) {
      $op = arg(2);
    }

    /*
    ** Compile a list of the administrative links:
    */
    switch ($op) {
      case "search":
        $output = search_type("node", url("admin/node/search"), $_POST["keys"]);
        break;
      case "edit":
        $output = node_admin_edit(arg(3));
        break;
      case "delete":
        $output = node_delete(array("nid" => arg(3)));
        break;
      case t("Preview"):
        $edit = node_validate($edit, $error);
        $output = node_preview($edit, $error);
        break;
      case t("Submit"):