chamilo-lms/main/inc/lib/link.lib.php

<?php
/* For licensing terms, see /license.txt */

/**
 * Function library for the links tool.
 *
 * This is a complete remake of the original link tool.
 * New features:
 * - Organize links into categories;
 * - favorites/bookmarks interface;
 * - move links up/down within a category;
 * - move categories up/down;
 * - expand/collapse all categories;
 * - add link to 'root' category => category-less link is always visible.
 *
 * @author Patrick Cool, complete remake (December 2003 - January 2004)
 * @author René Haentjens, CSV file import (October 2004)
 * @package chamilo.link
 */

/* FUNCTIONS */

class Link extends Model
{
    public $table;
    public $is_course_model = true;
    public $columns = array(
        'id',
        'c_id',
        'url',
        'title',
        'description',
        'category_id',
        'display_order',
        'on_homepage',
        'target',
        'session_id'
    );
    public $required = array('url', 'title');

    public function __construct()
    {
        $this->table = Database::get_course_table(TABLE_LINK);
    }

    public function save($params, $show_query = null)
    {
        $course_info = api_get_course_info();
        $params['session_id'] = api_get_session_id();
        $params['category_id'] = isset($params['category_id']) ? $params['category_id'] : 0;

        $id = parent::save($params, $show_query);
        if (!empty($id)) {
            api_item_property_update(
                $course_info,
                TOOL_LINK,
                $id,
                'LinkAdded',
                api_get_user_id()
            );
        }
        return $id;
    }

    function updateLink($linkId, $linkUrl)
    {
        $tblLink = Database :: get_course_table(TABLE_LINK);
        $linkUrl = Database::escape_string($linkUrl);
        $linkId = intval($linkId);
        $courseId = api_get_course_int_id();
        $session_id = api_get_session_id();
        if ($linkUrl != '') {
            $query = "UPDATE $tblLink SET url = '$linkUrl' WHERE id = $linkId AND c_id = $courseId AND session_id = $session_id";
            $resLink = Database::query($query);
        } else {
            return false;
        }
    }
}


/**
 * Used to add a link or a category
 * @param string $type, "link" or "category"
 * @todo replace strings by constants
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 */
function addlinkcategory($type)
{
    global $catlinkstatus;
    global $msgErr;

    $ok = true;

    $course_id = api_get_course_int_id();

    if ($type == 'link') {
        $tbl_link = Database :: get_course_table(TABLE_LINK);

        $title = Security :: remove_XSS(stripslashes($_POST['title']));
        $urllink = Security :: remove_XSS($_POST['urllink']);
        $description = Security :: remove_XSS($_POST['description']);
        $selectcategory = Security :: remove_XSS($_POST['selectcategory']);

        if ($_POST['onhomepage'] == '') {
            $onhomepage = 0;
        } else {
            $onhomepage = Security :: remove_XSS($_POST['onhomepage']);
        }

        if (empty($_POST['target_link'])) {
            $target = '_self'; // Default target.
        } else {
            $target = Security :: remove_XSS($_POST['target_link']);
        }

        $urllink = trim($urllink);
        $title = trim($title);
        $description = trim($description);

        // We ensure URL to be absolute.
        if (strpos($urllink, '://') === false) {
            $urllink = 'http://' . $urllink;
        }

        // If the title is empty, we use the URL as title.
        if ($title == '') {
            $title = $urllink;
        }

        // If the URL is invalid, an error occurs.
        // Ivan, 13-OCT-2010, Chamilo 1.8.8: Let us still tolerate PHP 5.1.x and avoid a specific bug in filter_var(), see http://bugs.php.net/51192
        //if (!filter_var($urllink, FILTER_VALIDATE_URL)) {
        if (!api_valid_url($urllink, true)) { // A check against an absolute URL
            $msgErr = get_lang('GiveURL');
            Display :: display_error_message(get_lang('GiveURL'));
            $ok = false;
        } else {
            // Looking for the largest order number for this category.
            $result = Database :: query(
                "SELECT MAX(display_order) FROM  " . $tbl_link . " WHERE c_id = $course_id AND category_id = '" . intval(
                    $_POST['selectcategory']
                ) . "'"
            );
            list ($orderMax) = Database :: fetch_row($result);
            $order = $orderMax + 1;

            $session_id = api_get_session_id();

            $sql = "INSERT INTO " . $tbl_link . " (c_id, url, title, description, category_id, display_order, on_homepage, target, session_id)
			        VALUES (" . $course_id . ", '" . Database :: escape_string(
                    $urllink
                ) . "','" . Database :: escape_string(
                    $title
                ) . "','" . Database :: escape_string($description) . "','" .
                Database :: escape_string(
                    $selectcategory
                ) . "','" . Database :: escape_string(
                    $order
                ) . "', '" . Database :: escape_string($onhomepage) . "','" .
                Database :: escape_string(
                    $target
                ) . "','" . Database :: escape_string($session_id) . "')";

            $catlinkstatus = get_lang('LinkAdded');
            Database :: query($sql);
            $link_id = Database :: insert_id();

            if ($link_id) {
                api_set_default_visibility($link_id, TOOL_LINK);
            }

            if ((api_get_setting(
                        'search_enabled'
                    ) == 'true') && $link_id && extension_loaded('xapian')
            ) {
                require_once api_get_path(
                        LIBRARY_PATH
                    ) . 'search/ChamiloIndexer.class.php';
                require_once api_get_path(
                        LIBRARY_PATH
                    ) . 'search/IndexableChunk.class.php';
                require_once api_get_path(
                        LIBRARY_PATH
                    ) . 'specific_fields_manager.lib.php';

                $course_int_id = api_get_course_int_id();

                $courseid = api_get_course_id();
                $specific_fields = get_specific_field_list();
                $ic_slide = new IndexableChunk();

                // Add all terms to db.
                $all_specific_terms = '';
                foreach ($specific_fields as $specific_field) {
                    if (isset ($_REQUEST[$specific_field['code']])) {
                        $sterms = trim($_REQUEST[$specific_field['code']]);
                        if (!empty ($sterms)) {
                            $all_specific_terms .= ' ' . $sterms;
                            $sterms = explode(',', $sterms);
                            foreach ($sterms as $sterm) {
                                $ic_slide->addTerm(
                                    trim($sterm),
                                    $specific_field['code']
                                );
                                add_specific_field_value(
                                    $specific_field['id'],
                                    $courseid,
                                    TOOL_LINK,
                                    $link_id,
                                    $sterm
                                );
                            }
                        }
                    }
                }

                // Build the chunk to index.
                $ic_slide->addValue('title', $title);
                $ic_slide->addCourseId($courseid);
                $ic_slide->addToolId(TOOL_LINK);
                $xapian_data = array(
                    SE_COURSE_ID => $courseid,
                    SE_TOOL_ID => TOOL_LINK,
                    SE_DATA => array(
                        'link_id' => (int)$link_id
                    ),
                    SE_USER => (int)api_get_user_id(),

                );
                $ic_slide->xapian_data = serialize($xapian_data);
                $description = $all_specific_terms . ' ' . $description;
                $ic_slide->addValue('content', $description);

                // Add category name if set.
                if (isset ($_POST['selectcategory']) && $selectcategory > 0) {
                    $table_link_category = Database :: get_course_table(
                        TABLE_LINK_CATEGORY
                    );
                    $sql_cat = 'SELECT * FROM %s WHERE id=%d AND c_id = %d LIMIT 1';
                    $sql_cat = sprintf(
                        $sql_cat,
                        $table_link_category,
                        (int)$selectcategory,
                        $course_int_id
                    );
                    $result = Database :: query($sql_cat);
                    if (Database :: num_rows($result) == 1) {
                        $row = Database :: fetch_array($result);
                        $ic_slide->addValue('category', $row['category_title']);
                    }
                }

                $di = new ChamiloIndexer();
                isset ($_POST['language']) ? $lang = Database :: escape_string(
                    $_POST['language']
                ) : $lang = 'english';
                $di->connectDb(null, null, $lang);
                $di->addChunk($ic_slide);

                // Index and return search engine document id.
                $did = $di->index();
                if ($did) {
                    // Save it to db.
                    $tbl_se_ref = Database :: get_main_table(
                        TABLE_MAIN_SEARCH_ENGINE_REF
                    );
                    $sql = 'INSERT INTO %s (c_id, id, course_code, tool_id, ref_id_high_level, search_did)
					                        VALUES (NULL , \'%s\', \'%s\', %s, %s)';
                    $sql = sprintf(
                        $sql,
                        $tbl_se_ref,
                        $course_int_id,
                        $courseid,
                        TOOL_LINK,
                        $link_id,
                        $did
                    );
                    Database :: query($sql);
                }
            }
            unset ($urllink, $title, $description, $selectcategory);
            Display :: display_confirmation_message(get_lang('LinkAdded'));
        }
    } elseif ($type == 'category') {
        $tbl_categories = Database :: get_course_table(TABLE_LINK_CATEGORY);

        $category_title = trim($_POST['category_title']);
        $description = trim($_POST['description']);

        if (empty($category_title)) {
            $msgErr = get_lang('GiveCategoryName');
            Display :: display_error_message(get_lang('GiveCategoryName'));
            $ok = false;
        } else {
            // Looking for the largest order number for this category.
            $result = Database :: query(
                "SELECT MAX(display_order) FROM  " . $tbl_categories . " WHERE c_id = $course_id "
            );
            list ($orderMax) = Database :: fetch_row($result);
            $order = $orderMax + 1;
            $order = intval($order);
            $session_id = api_get_session_id();
            $sql = "INSERT INTO " . $tbl_categories . " (c_id, category_title, description, display_order, session_id)
			        VALUES (" . $course_id . ", '" . Database::escape_string(
                    $category_title
                ) . "', '" . Database::escape_string(
                    $description
                ) . "', '$order', '$session_id')";
            Database :: query($sql);

            $linkId = Database :: insert_id();
            if ($linkId) {
                // add link_category visibility
                // course ID is taken from context in api_set_default_visibility
                api_set_default_visibility($linkId, TOOL_LINK_CATEGORY);
            }

            $catlinkstatus = get_lang('CategoryAdded');
            unset ($category_title, $description);
            Display :: display_confirmation_message(get_lang('CategoryAdded'));
        }
    }

    // "WHAT'S NEW" notification : update last tool Edit.
    if ($type == 'link') {
        global $_user;
        global $_course;
        global $nameTools;
        api_item_property_update(
            $_course,
            TOOL_LINK,
            $link_id,
            'LinkAdded',
            $_user['user_id']
        );
    }
    return $ok;
}

/**
 * Used to delete a link or a category
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 */
function deletelinkcategory($type)
{
    global $catlinkstatus;
    global $_course;
    $session_id = api_get_session_id();
    $tbl_link = Database :: get_course_table(TABLE_LINK);
    $tbl_categories = Database :: get_course_table(TABLE_LINK_CATEGORY);
    $TABLE_ITEM_PROPERTY = Database :: get_course_table(TABLE_ITEM_PROPERTY);

    $course_id = api_get_course_int_id();

    if ($type == 'link') {
        global $id;
        // -> Items are no longer fysically deleted, but the visibility is set to 2 (in item_property).
        // This will make a restore function possible for the platform administrator.
        if (isset ($_GET['id']) && $_GET['id'] == strval(intval($_GET['id']))) {
            $sql = "UPDATE $tbl_link SET on_homepage='0' WHERE c_id = $course_id AND id='" . intval(
                    $_GET['id']
                ) . "'";
            Database :: query($sql);
        }
        api_item_property_update(
            $_course,
            TOOL_LINK,
            $id,
            'delete',
            api_get_user_id()
        );
        delete_link_from_search_engine(api_get_course_id(), $id);
        $catlinkstatus = get_lang('LinkDeleted');
        unset ($id);
        Display :: display_confirmation_message(get_lang('LinkDeleted'));
    }

    if ($type == 'category') {
        global $id;
        if (isset ($_GET['id']) && !empty ($_GET['id'])) {
            // First we delete the category itself and afterwards all the links of this category.
            $sql = "DELETE FROM " . $tbl_categories . " WHERE c_id = $course_id AND id='" . intval(
                    $_GET['id']
                ) . "'";
            Database :: query($sql);
            $sql = "DELETE FROM " . $tbl_link . " WHERE c_id = $course_id AND category_id='" . intval(
                    $_GET['id']
                ) . "'";
            $catlinkstatus = get_lang('CategoryDeleted');
            unset ($id);
            Database :: query($sql);
            api_item_property_update(
                $_course,
                TOOL_LINK_CATEGORY,
                $_GET['id'],
                'delete',
                api_get_user_id()
            );
            Display :: display_confirmation_message(
                get_lang('CategoryDeleted')
            );
        }
    }
}

/**
 * Removes a link from search engine database
 *
 * @param string $course_id Course code
 * @param int $document_id Document id to delete
 */
function delete_link_from_search_engine($course_id, $link_id)
{
    // Remove from search engine if enabled.
    if (api_get_setting('search_enabled') == 'true') {
        $tbl_se_ref = Database :: get_main_table(TABLE_MAIN_SEARCH_ENGINE_REF);
        $sql = 'SELECT * FROM %s WHERE course_code=\'%s\' AND tool_id=\'%s\' AND ref_id_high_level=%s LIMIT 1';
        $sql = sprintf($sql, $tbl_se_ref, $course_id, TOOL_LINK, $link_id);
        $res = Database :: query($sql);
        if (Database :: num_rows($res) > 0) {
            $row = Database :: fetch_array($res);
            require_once api_get_path(
                    LIBRARY_PATH
                ) . 'search/ChamiloIndexer.class.php';
            $di = new ChamiloIndexer();
            $di->remove_document((int)$row['search_did']);
        }
        $sql = 'DELETE FROM %s WHERE course_code=\'%s\' AND tool_id=\'%s\' AND ref_id_high_level=%s LIMIT 1';
        $sql = sprintf($sql, $tbl_se_ref, $course_id, TOOL_LINK, $link_id);
        Database :: query($sql);

        // Remove terms from db.
        require_once(api_get_path(
                LIBRARY_PATH
            ) . 'specific_fields_manager.lib.php');
        delete_all_values_for_item($course_id, TOOL_DOCUMENT, $link_id);
    }
}


/**
 *
 * Get link info
 * @param int link id
 * @return array link info
 *
 * */

function get_link_info($id)
{
    $tbl_link = Database :: get_course_table(TABLE_LINK);
    $course_id = api_get_course_int_id();
    $sql = "SELECT * FROM " . $tbl_link . " WHERE c_id = $course_id AND id='" . intval(
            $id
        ) . "' ";
    $result = Database::query($sql);

    if (Database::num_rows($result)) {
        $data = Database::fetch_array($result);
    }
    return $data;
}

/**
 * Used to edit a link or a category
 * @todo Rewrite the whole links tool because it is becoming completely cluttered,
 *       code does not follow the coding conventions, does not use html_quickform, ...
 *       Some features were patched in.
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 * @todo replace the globals with the appropriate $_POST or $_GET values
 */
function editlinkcategory($type)
{

    global $catlinkstatus;
    global $id;
    global $submit_link;
    global $submit_category;
    global $_user;
    global $_course;
    global $nameTools;
    global $urllink;
    global $title;
    global $description;
    global $category;
    global $selectcategory;
    global $description;
    global $category_title;
    global $onhomepage;
    global $target_link;

    $tbl_link = Database :: get_course_table(TABLE_LINK);
    $tbl_categories = Database :: get_course_table(TABLE_LINK_CATEGORY);

    $course_id = api_get_course_int_id();

    if ($type == 'link') {

        // This is used to populate the link-form with the info found in the database.
        if (!empty ($_GET['id'])) {
            $sql = "SELECT * FROM " . $tbl_link . " WHERE c_id = $course_id AND id='" . intval(
                    $_GET['id']
                ) . "'";
            $result = Database :: query($sql);
            if ($myrow = Database :: fetch_array($result)) {
                $urllink = $myrow['url'];
                $title = $myrow['title'];
                $description = $myrow['description'];
                $category = $myrow['category_id'];
                if ($myrow['on_homepage'] != 0) {
                    $onhomepage = 'checked';
                }
                $target_link = $myrow['target'];
            }
        }

        // This is used to put the modified info of the link-form into the database.
        if ($_POST['submitLink']) {

            // Ivan, 13-OCT-2010: It is a litle bit messy code below, just in case I added some extra-security checks here.
            $_POST['urllink'] = trim($_POST['urllink']);
            $_POST['title'] = trim(Security :: remove_XSS($_POST['title']));
            $_POST['description'] = trim(
                Security :: remove_XSS($_POST['description'])
            );
            $_POST['selectcategory'] = intval($_POST['selectcategory']);
            $_POST['id'] = intval($_POST['id']);

            // We ensure URL to be absolute.
            if (strpos($_POST['urllink'], '://') === false) {
                $_POST['urllink'] = 'http://' . $_POST['urllink'];
            }

            // If the title is empty, we use the URL as title.
            if ($_POST['title'] == '') {
                $_POST['title'] = $_POST['urllink'];
            }

            // If the URL is invalid, an error occurs.
            // Ivan, 13-OCT-2010, Chamilo 1.8.8: Let us still tolerate PHP 5.1.x and avoid a specific bug in filter_var(), see http://bugs.php.net/51192
            //if (!filter_var($urllink, FILTER_VALIDATE_URL)) {
            if (!api_valid_url(
                $urllink,
                true
            )
            ) { // A check against an absolute URL.
                $msgErr = get_lang('GiveURL');
                Display :: display_error_message(get_lang('GiveURL'));
                return false;
            }

            $onhomepage = Security :: remove_XSS($_POST['onhomepage']);
            $target = Database::escape_string($_POST['target_link']);
            if (empty ($mytarget)) {
                $mytarget = '_self';
            }
            $mytarget = ",target='" . $target . "'";

            // Finding the old category_id.
            $sql = "SELECT * FROM " . $tbl_link . " WHERE c_id = $course_id AND id='" . intval(
                    $_POST['id']
                ) . "'";
            $result = Database :: query($sql);
            $row = Database :: fetch_array($result);
            $category_id = $row['category_id'];

            if ($category_id != $_POST['selectcategory']) {
                $sql = "SELECT MAX(display_order) FROM " . $tbl_link . " WHERE c_id = $course_id AND category_id='" . intval(
                        $_POST['selectcategory']
                    ) . "'";
                $result = Database :: query($sql);
                list ($max_display_order) = Database :: fetch_row($result);
                $max_display_order++;
            } else {
                $max_display_order = $row['display_order'];
            }

            $sql = "UPDATE " . $tbl_link . " SET " .
                "url='" . Database :: escape_string($_POST['urllink']) . "', " .
                "title='" . Database :: escape_string($_POST['title']) . "', " .
                "description='" . Database :: escape_string(
                    $_POST['description']
                ) . "', " .
                "category_id='" . Database :: escape_string(
                    $_POST['selectcategory']
                ) . "', " .
                "display_order='" . $max_display_order . "', " .
                "on_homepage='" . Database :: escape_string(
                    $onhomepage
                ) . " ' $mytarget " .
                " WHERE c_id = $course_id AND id='" . intval(
                    $_POST['id']
                ) . "'";
            Database :: query($sql);

            // Update search enchine and its values table if enabled.
            if (api_get_setting('search_enabled') == 'true') {
                $link_id = intval($_POST['id']);

                $course_int_id = api_get_course_int_id();

                $course_id = api_get_course_id();
                $link_url = Database :: escape_string($_POST['urllink']);
                $link_title = Database :: escape_string($_POST['title']);
                $link_description = Database :: escape_string(
                    $_POST['description']
                );

                // Actually, it consists on delete terms from db, insert new ones, create a new search engine document, and remove the old one.
                // Get search_did.
                $tbl_se_ref = Database :: get_main_table(
                    TABLE_MAIN_SEARCH_ENGINE_REF
                );
                $sql = 'SELECT * FROM %s WHERE course_code=\'%s\' AND tool_id=\'%s\' AND ref_id_high_level=%s LIMIT 1';
                $sql = sprintf(
                    $sql,
                    $tbl_se_ref,
                    $course_id,
                    TOOL_LINK,
                    $link_id
                );
                $res = Database :: query($sql);

                if (Database :: num_rows($res) > 0) {
                    require_once api_get_path(
                            LIBRARY_PATH
                        ) . 'search/ChamiloIndexer.class.php';
                    require_once api_get_path(
                            LIBRARY_PATH
                        ) . 'search/IndexableChunk.class.php';
                    require_once api_get_path(
                            LIBRARY_PATH
                        ) . 'specific_fields_manager.lib.php';

                    $se_ref = Database :: fetch_array($res);
                    $specific_fields = get_specific_field_list();
                    $ic_slide = new IndexableChunk();

                    $all_specific_terms = '';
                    foreach ($specific_fields as $specific_field) {
                        delete_all_specific_field_value(
                            $course_id,
                            $specific_field['id'],
                            TOOL_LINK,
                            $link_id
                        );
                        if (isset ($_REQUEST[$specific_field['code']])) {
                            $sterms = trim($_REQUEST[$specific_field['code']]);
                            if (!empty ($sterms)) {
                                $all_specific_terms .= ' ' . $sterms;
                                $sterms = explode(',', $sterms);
                                foreach ($sterms as $sterm) {
                                    $ic_slide->addTerm(
                                        trim($sterm),
                                        $specific_field['code']
                                    );
                                    add_specific_field_value(
                                        $specific_field['id'],
                                        $course_id,
                                        TOOL_LINK,
                                        $link_id,
                                        $sterm
                                    );
                                }
                            }
                        }
                    }

                    // Build the chunk to index.
                    $ic_slide->addValue("title", $link_title);
                    $ic_slide->addCourseId($course_id);
                    $ic_slide->addToolId(TOOL_LINK);
                    $xapian_data = array(
                        SE_COURSE_ID => $course_id,
                        SE_TOOL_ID => TOOL_LINK,
                        SE_DATA => array(
                            'link_id' => (int)$link_id
                        ),
                        SE_USER => (int)api_get_user_id(),

                    );
                    $ic_slide->xapian_data = serialize($xapian_data);
                    $link_description = $all_specific_terms . ' ' . $link_description;
                    $ic_slide->addValue('content', $link_description);

                    // Add category name if set.
                    if (isset ($_POST['selectcategory']) && $selectcategory > 0) {
                        $table_link_category = Database :: get_course_table(
                            TABLE_LINK_CATEGORY
                        );
                        $sql_cat = 'SELECT * FROM %s WHERE id=%d and c_id = %d LIMIT 1';
                        $sql_cat = sprintf(
                            $sql_cat,
                            $table_link_category,
                            (int)$selectcategory,
                            $course_int_id
                        );
                        $result = Database :: query($sql_cat);
                        if (Database :: num_rows($result) == 1) {
                            $row = Database :: fetch_array($result);
                            $ic_slide->addValue(
                                'category',
                                $row['category_title']
                            );
                        }
                    }

                    $di = new ChamiloIndexer();
                    isset ($_POST['language']) ? $lang = Database :: escape_string(
                        $_POST['language']
                    ) : $lang = 'english';
                    $di->connectDb(null, null, $lang);
                    $di->remove_document((int)$se_ref['search_did']);
                    $di->addChunk($ic_slide);

                    // Index and return search engine document id.
                    $did = $di->index();
                    if ($did) {
                        // Save it to db.
                        $sql = 'DELETE FROM %s WHERE course_code=\'%s\' AND tool_id=\'%s\' AND ref_id_high_level=\'%s\'';
                        $sql = sprintf(
                            $sql,
                            $tbl_se_ref,
                            $course_id,
                            TOOL_LINK,
                            $link_id
                        );
                        Database :: query($sql);
                        $sql = 'INSERT INTO %s (c_id, id, course_code, tool_id, ref_id_high_level, search_did)
						        VALUES (NULL , \'%s\', \'%s\', %s, %s)';
                        $sql = sprintf(
                            $sql,
                            $tbl_se_ref,
                            $course_int_id,
                            $course_id,
                            TOOL_LINK,
                            $link_id,
                            $did
                        );
                        Database :: query($sql);
                    }
                }
            }
            // "WHAT'S NEW" notification: update table last_toolEdit.
            api_item_property_update(
                $_course,
                TOOL_LINK,
                $_POST['id'],
                'LinkUpdated',
                $_user['user_id']
            );
            Display :: display_confirmation_message(get_lang('LinkModded'));
        }
    }

    if ($type == 'category') {

        // This is used to populate the category-form with the info found in the database.
        if (!$submit_category) {
            $sql = "SELECT * FROM " . $tbl_categories . " WHERE c_id = $course_id AND id='" . intval(
                    $_GET['id']
                ) . "'";
            $result = Database :: query($sql);
            if ($myrow = Database :: fetch_array($result)) {
                $category_title = $myrow['category_title'];
                $description = $myrow['description'];
            }
        }

        // This is used to put the modified info of the category-form into the database.
        if ($submit_category) {
            $sql = "UPDATE " . $tbl_categories . "
                    SET category_title='" . Database :: escape_string(
                    $_POST['category_title']
                ) . "', description='" . Database :: escape_string(
                    $_POST['description']
                ) . "'
			        WHERE c_id = $course_id AND id='" . Database :: escape_string(
                    $_POST['id']
                ) . "'";
            Database :: query($sql);
            Display :: display_confirmation_message(get_lang('CategoryModded'));
        }
    }
    return true; // On errors before this statement, exit from this function by returning false value.
}

/**
 * Creates a correct $view for in the URL
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 */
function makedefaultviewcode($locatie)
{
    global $aantalcategories, $view;
    for ($j = 0; $j <= $aantalcategories - 1; $j++) {
        $view[$j] = 0;
    }
    $view[intval($locatie)] = '1';
}

/**
 * Changes the visibility of a link
 * @todo add the changing of the visibility of a course
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 */
function change_visibility($id, $scope)
{
    global $_course, $_user;
    if ($scope == TOOL_LINK) {
        api_item_property_update(
            $_course,
            TOOL_LINK,
            $id,
            $_GET['action'],
            $_user['user_id']
        );
        Display :: display_confirmation_message(get_lang('VisibilityChanged'));
    } elseif ($scope == TOOL_LINK_CATEGORY) {
        api_item_property_update(
            $_course,
            TOOL_LINK_CATEGORY,
            $id,
            $_GET['action'],
            $_user['user_id']
        );
        Display :: display_confirmation_message(get_lang('VisibilityChanged'));
    }
}

/**
 * Generate SQL to select all the links categories in the current course and
 * session
 * @return string SQL query (to be executed)
 */
function getLinkCategories($courseId, $sessionId)
{
    $tblLinkCategory = Database :: get_course_table(TABLE_LINK_CATEGORY);
    $tblItemProperty = Database :: get_course_table(TABLE_ITEM_PROPERTY);

    // Condition for the session.
    $sessionCondition = api_get_session_condition($sessionId, true, true);

    $sql = "SELECT *, linkcat.id FROM $tblLinkCategory linkcat,
                 $tblItemProperty itemproperties
             WHERE  itemproperties.tool = '" . TOOL_LINK_CATEGORY . "' AND
                    linkcat.id = itemproperties.ref AND
                    (itemproperties.visibility = '0' OR itemproperties.visibility = '1')
                    $sessionCondition AND
                    linkcat.c_id = " . $courseId . " AND
                    itemproperties.c_id = " . $courseId . "
                    ORDER BY linkcat.display_order DESC";
    return Database::query($sql);
}

/**
 * Displays all the links of a given category.
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 */
function showlinksofcategory($catid)
{
    global $is_allowed, $charset, $urlview, $up, $down, $_user, $token;

    $tbl_link = Database :: get_course_table(TABLE_LINK);
    $TABLE_ITEM_PROPERTY = Database :: get_course_table(TABLE_ITEM_PROPERTY);

    // Condition for the session.
    $session_id = api_get_session_id();
    $condition_session = api_get_session_condition($session_id, true, true);
    $catid = intval($catid);

    $course_id = api_get_course_int_id();

    $sqlLinks = "SELECT *, link.id FROM " . $tbl_link . " link, " . $TABLE_ITEM_PROPERTY . " itemproperties
				 WHERE  itemproperties.tool='" . TOOL_LINK . "' AND
						link.id=itemproperties.ref AND
						link.category_id='" . $catid . "' AND
						(itemproperties.visibility='0' OR itemproperties.visibility='1')
						$condition_session AND
						link.c_id = " . $course_id . " AND
						itemproperties.c_id = " . $course_id . "
						ORDER BY link.display_order DESC";
    $result = Database :: query($sqlLinks);
    $numberoflinks = Database :: num_rows($result);
    if ($numberoflinks > 0) {
        echo '<table class="data_table" width="100%">';
        $i = 1;
        while ($myrow = Database :: fetch_array($result)) {


            // Validacion when belongs to a session.
            $session_img = api_get_session_image(
                $myrow['session_id'],
                $_user['status']
            );

            $css_class = $i % 2 == 0 ? $css_class = 'row_odd' : $css_class = 'row_even';

            $link_validator = '';
            if (api_is_allowed_to_edit(null, true)) {
                $link_validator = '' . Display::url(
                        Display::return_icon(
                            'preview_view.png',
                            get_lang('CheckURL'),
                            array(),
                            16
                        ),
                        '#',
                        array(
                            'onclick' => "check_url('" . $myrow['id'] . "', '" . addslashes(
                                $myrow['url']
                            ) . "');"
                        )
                    );
                $link_validator .= Display::span(
                    '',
                    array('id' => 'url_id_' . $myrow['id'])
                );
            }

            if ($myrow['visibility'] == '1') {
                echo '<tr class="' . $css_class . '">';
                echo '<td align="center" valign="middle" width="15">';
                echo '<a href="link_goto.php?' . api_get_cidreq(
                    ) . '&amp;link_id=' . $myrow['id'] . '&amp;link_url=' . urlencode(
                        $myrow['url']
                    ) . '" target="_blank">
    			         <img src="../../main/img/link.gif" border="0" alt="' . get_lang(
                        'Link'
                    ) . '"/></a></td>
    			         <td width="80%" valign="top"><a href="link_goto.php?' . api_get_cidreq(
                    ) . '&amp;link_id=' . $myrow['id'] . '&amp;link_url=' . urlencode(
                        $myrow['url']
                    ) . '" target="' . $myrow['target'] . '">';
                echo Security :: remove_XSS($myrow['title']);
                echo '</a>';
                echo $link_validator;
                echo $session_img;
                echo '<br />' . $myrow['description'];
            } else {
                if (api_is_allowed_to_edit(null, true)) {
                    echo '<tr class="' . $css_class . '">';
                    echo '<td align="center" valign="middle" width="15"><a href="link_goto.php?' . api_get_cidreq(
                        ) . '&amp;link_id=' . $myrow['id'] . "&amp;link_url=" . urlencode(
                            $myrow['url']
                        ) . '" target="_blank" class="invisible">';
                    echo Display :: return_icon(
                        'link_na.gif',
                        get_lang('Link')
                    ), '</a>';
                    echo '</td><td width="80%" valign="top"><a href="link_goto.php?', api_get_cidreq(
                    ), '&amp;link_id=', $myrow['id'], '&amp;link_url=', urlencode(
                        $myrow['url']
                    ), '" target="', $myrow['target'], '"  class="invisible">';
                    echo Security :: remove_XSS($myrow['url']);
                    echo "</a>";
                    echo $link_validator;
                    echo $session_img, '<br />', $myrow['title'];
                }
            }

            echo '<td style="text-align:center;">';
            if (api_is_allowed_to_edit(null, true)) {
                if ($session_id == $myrow['session_id']) {
                    echo '<a href="' . api_get_self() . '?' . api_get_cidreq(
                        ) . '&amp;sec_token=' . $token . '&amp;action=editlink&amp;category=' . (!empty ($category) ? $category : '') . '&amp;id=' . $myrow['id'] . '&amp;urlview=' . $urlview . '" title="' . get_lang(
                            'Modify'
                        ) . '">' .
                        Display :: return_icon(
                            'edit.png',
                            get_lang('Modify'),
                            array(),
                            ICON_SIZE_SMALL
                        ) . '</a>';

                    // DISPLAY MOVE UP COMMAND only if it is not the top link.
                    /*
                    if ($i != 1) {
                        echo '<a href="' . api_get_self() . '?' . api_get_cidreq() .  '&amp;sec_token='.$token.'&amp;urlview=' . $urlview . '&amp;up=', $myrow[0], '" title="' . get_lang('Up') . '">' . Display :: return_icon('up.png', get_lang('Up'), array (), ICON_SIZE_SMALL) . '', "</a>\n";
                    } else {
                        echo Display :: return_icon('up_na.png', get_lang('Up'), array (), ICON_SIZE_SMALL) . '</a>';
                    }

                    // DISPLAY MOVE DOWN COMMAND only if it is not the bottom link.
                    if ($i < $numberoflinks) {
                        echo '<a href="' . api_get_self() . '?' . api_get_cidreq() .  '&amp;sec_token='.$token.'&amp;urlview=' . $urlview . '&amp;down=' . $myrow[0] . '" title="' . get_lang('Down') . '">' . Display :: return_icon('down.png', get_lang('Down'), array (), ICON_SIZE_SMALL) . '', "</a>\n";
                    } else {
                        echo Display :: return_icon('down_na.png', get_lang('Down'), array (), ICON_SIZE_SMALL) . '', "</a>\n";
                    }*/

                    if ($myrow['visibility'] == '1') {
                        echo '<a href="link.php?' . api_get_cidreq(
                            ) . '&amp;sec_token=' . $token . '&amp;action=invisible&amp;id=' . $myrow['id'] . '&amp;scope=link&amp;urlview=' . $urlview . '" title="' . get_lang(
                                'Hide'
                            ) . '">' .
                            Display :: return_icon(
                                'visible.png',
                                get_lang('Hide'),
                                array(),
                                ICON_SIZE_SMALL
                            ) . '</a>';
                    }
                    if ($myrow['visibility'] == '0') {
                        echo ' <a href="link.php?' . api_get_cidreq(
                            ) . '&amp;sec_token=' . $token . '&amp;action=visible&amp;id=' . $myrow['id'] . '&amp;scope=link&amp;urlview=' . $urlview . '" title="' . get_lang(
                                'Show'
                            ) . '">' .
                            Display :: return_icon(
                                'invisible.png',
                                get_lang('Show'),
                                array(),
                                ICON_SIZE_SMALL
                            ) . '</a>';
                    }
                    echo ' <a href="' . api_get_self() . '?' . api_get_cidreq(
                        ) . '&amp;sec_token=' . $token . '&amp;action=deletelink&amp;id=', $myrow['id'], '&amp;urlview=', $urlview, "\" onclick=\"javascript: if(!confirm('" . get_lang(
                            'LinkDelconfirm'
                        ) . "')) return false;\" title=\"" . get_lang(
                            'Delete'
                        ) . '">' .
                        Display :: return_icon(
                            'delete.png',
                            get_lang('Delete'),
                            array(),
                            ICON_SIZE_SMALL
                        ) . '</a>';

                } else {
                    echo Display :: return_icon(
                        'edit_na.png',
                        get_lang('EditionNotAvailableFromSession'),
                        array(),
                        ICON_SIZE_SMALL
                    ); //get_lang('EditionNotAvailableFromSession');
                }
            }
            echo '</td></tr>';
            $i++;
        }
        echo '</table>';
    }
}

/**
 * Displays the edit, delete and move icons
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 */
function showcategoryadmintools($categoryid)
{

    global $urlview, $aantalcategories, $catcounter, $token;
    echo '<a href="' . api_get_self() . '?' . api_get_cidreq(
        ) . '&amp;sec_token=' . $token . '&amp;action=editcategory&amp;id=' . $categoryid . '&amp;urlview=' . $urlview . '" title=' . get_lang(
            'Modify'
        ) . '">' . Display :: return_icon(
            'edit.png',
            get_lang('Modify'),
            array(),
            ICON_SIZE_SMALL
        ) . '</a>';

    // DISPLAY MOVE UP COMMAND only if it is not the top link.
    if ($catcounter != 1) {
        echo '<a href="' . api_get_self() . '?' . api_get_cidreq(
            ) . '&amp;sec_token=' . $token . '&amp;catmove=true&amp;up=', $categoryid, '&amp;urlview=' . $urlview . '" title="' . get_lang(
                'Up'
            ) . '">' . Display :: return_icon(
                'up.png',
                get_lang('Up'),
                array(),
                ICON_SIZE_SMALL
            ) . '</a>';
    } else {
        echo Display :: return_icon(
                'up_na.png',
                get_lang('Up'),
                array(),
                ICON_SIZE_SMALL
            ) . '</a>';
    }

    // DISPLAY MOVE DOWN COMMAND only if it is not the bottom link.
    if ($catcounter < $aantalcategories) {
        echo '<a href="' . api_get_self() . '?' . api_get_cidreq(
            ) . '&amp;sec_token=' . $token . '&amp;catmove=true&amp;down=' . $categoryid . '&amp;urlview=' . $urlview . '">
					' . Display :: return_icon(
                'down.png',
                get_lang('Down'),
                array(),
                ICON_SIZE_SMALL
            ) . '</a>';
    } else {
        echo Display :: return_icon(
                'down_na.png',
                get_lang('Down'),
                array(),
                ICON_SIZE_SMALL
            ) . '</a>';
    }
    echo '<a href="' . api_get_self() . '?' . api_get_cidreq(
        ) . '&amp;sec_token=' . $token . '&amp;action=deletecategory&amp;id=', $categoryid, "&amp;urlview=$urlview\" onclick=\"javascript: if(!confirm('" . get_lang(
            'CategoryDelconfirm'
        ) . "')) return false;\">", Display :: return_icon(
            'delete.png',
            get_lang('Delete'),
            array(),
            ICON_SIZE_SMALL
        ) . '</a>';
    $catcounter++;
}

/**
 * move a link or a linkcategory up or down
 * @author Patrick Cool <patrick.cool@UGent.be>, Ghent University
 */
function movecatlink($catlinkid)
{
    global $catmove;
    global $up;
    global $down;
    $tbl_link = Database :: get_course_table(TABLE_LINK);
    $tbl_categories = Database :: get_course_table(TABLE_LINK_CATEGORY);
    $course_id = api_get_course_int_id();

    if (!empty ($down)) {
        $thiscatlinkId = intval($down);
        $sortDirection = 'DESC';
    }
    if (!empty ($up)) {
        $thiscatlinkId = intval($up);
        $sortDirection = 'ASC';
    }

    // We check if it is a category we are moving or a link. If it is a category, a querystring catmove = true is present in the url.
    if ($catmove == 'true') {
        $movetable = $tbl_categories;
        $catid = $catlinkid;
    } else {
        $movetable = $tbl_link;
        // Getting the category of the link.
        if (!empty ($thiscatlinkId)) {
            $sql = "SELECT category_id FROM " . $movetable . " WHERE c_id = $course_id AND id='$thiscatlinkId'";
            $result = Database :: query($sql);
            $catid = Database :: fetch_array($result);
        }
    }

    // This code is copied and modified from announcements.php.
    if (!empty($sortDirection)) {

        if (!in_array(trim(strtoupper($sortDirection)), array('ASC', 'DESC'))) {
            $sortDirection = 'ASC';
        }

        if ($catmove == 'true') {
            $sqlcatlinks = "SELECT id, display_order FROM " . $movetable . " WHERE c_id = $course_id  ORDER BY display_order $sortDirection";
        } else {
            $sqlcatlinks = "SELECT id, display_order FROM " . $movetable . "
                			WHERE c_id = $course_id AND category_id='" . $catid[0] . "'
                			ORDER BY display_order $sortDirection";
        }
        $linkresult = Database :: query($sqlcatlinks);
        while ($sortrow = Database :: fetch_array($linkresult)) {
            // STEP 2 : FOUND THE NEXT ANNOUNCEMENT ID AND ORDER, COMMIT SWAP
            // This part seems unlogic, but it isn't . We first look for the current link with the querystring ID
            // and we know the next iteration of the while loop is the next one. These should be swapped.
            if (isset ($thislinkFound) && $thislinkFound) {
                $nextlinkId = $sortrow['id'];
                $nextlinkOrdre = $sortrow['display_order'];

                Database :: query(
                    "UPDATE " . $movetable . "
				                                         SET display_order = '$nextlinkOrdre'
				                                         WHERE c_id = $course_id  AND id =  '$thiscatlinkId'"
                );

                Database :: query(
                    "UPDATE " . $movetable . "
				                                         SET display_order = '$thislinkOrdre'
				                                         WHERE c_id = $course_id  AND id =  '$nextlinkId'"
                );

                break;
            }
            if ($sortrow['id'] == $thiscatlinkId) {
                $thislinkOrdre = $sortrow['display_order'];
                $thislinkFound = true;
            }
        }
    }

    Display :: display_confirmation_message(get_lang('LinkMoved'));
}

/**
 * CSV file import functions
 * @author René Haentjens , Ghent University
 */
function get_cat($catname)
{
    // Get category id (existing or make new).
    $tbl_categories = Database :: get_course_table(TABLE_LINK_CATEGORY);
    $course_id = api_get_course_int_id();

    $result = Database :: query(
        "SELECT id FROM " . $tbl_categories . " WHERE c_id = $course_id AND category_title='" . Database::escape_string(
            $catname
        ) . "'"
    );
    if (Database :: num_rows($result) >= 1 && ($row = Database :: fetch_array(
            $result
        ))
    ) {
        return $row['id']; // Several categories with same name: take the first.
    }

    $result = Database :: query(
        "SELECT MAX(display_order) FROM " . $tbl_categories . " WHERE c_id = $course_id "
    );
    list ($max_order) = Database :: fetch_row($result);
    Database :: query(
        "INSERT INTO " . $tbl_categories . " (c_id, category_title, description, display_order)
					   VALUES (" . $course_id . ", '" . Database::escape_string(
            $catname
        ) . "','','" . ($max_order + 1) . "')"
    );
    return Database :: insert_id();
}

/**
 * CSV file import functions
 * @author René Haentjens , Ghent University
 */
function put_link($url, $cat, $title, $description, $on_homepage, $hidden)
{
    $tbl_link = Database :: get_course_table(TABLE_LINK);

    $course_id = api_get_course_int_id();


    $urleq = "url='" . Database :: escape_string($url) . "'";
    $cateq = "category_id=" . intval($cat);

    $result = Database :: query(
        "SELECT id FROM $tbl_link WHERE c_id = $course_id AND " . $urleq . ' AND ' . $cateq
    );

    if (Database :: num_rows($result) >= 1 && ($row = Database :: fetch_array(
            $result
        ))
    ) {
        Database :: query(
            "UPDATE $tbl_link set title='" . Database :: escape_string(
                $title
            ) . "', description='" . Database :: escape_string($description) . "'
		WHERE c_id = $course_id AND  id='" . Database :: escape_string(
                $row['id']
            ) . "'"
        );

        $ipu = 'LinkUpdated';
        $rv = 1; // 1 = upd
    } else {
        // Add new link
        $result = Database :: query(
            "SELECT MAX(display_order) FROM  $tbl_link WHERE c_id = $course_id AND category_id='" . intval(
                $cat
            ) . "'"
        );
        list ($max_order) = Database :: fetch_row($result);

        Database :: query(
            "INSERT INTO $tbl_link (c_id, url, title, description, category_id, display_order, on_homepage)
						   VALUES (" . api_get_course_int_id(
            ) . ", '" . Database :: escape_string(
                $url
            ) . "','" . Database :: escape_string(
                $title
            ) . "','" . Database :: escape_string(
                $description
            ) . "','" . intval($cat) . "','" . (intval(
                    $max_order
                ) + 1) . "','" . intval($on_homepage) . "')"
        );

        $id = Database :: insert_id();
        $ipu = 'LinkAdded';
        $rv = 2; // 2 = new
    }
    global $_course, $nameTools, $_user;
    api_item_property_update($_course, TOOL_LINK, $id, $ipu, $_user['user_id']);

    if ($hidden && $ipu == 'LinkAdded') {
        api_item_property_update(
            $_course,
            TOOL_LINK,
            $id,
            'invisible',
            $_user['user_id']
        );
    }
    return $rv;
}

/**
 * CSV file import functions
 * @author René Haentjens , Ghent University
 */
function import_link($linkdata)
{
    // url, category_id, title, description, ...

    // Field names used in the uploaded file
    $known_fields = array(
        'url',
        'category',
        'title',
        'description',
        'on_homepage',
        'hidden'
    );
    $hide_fields = array(
        'kw',
        'kwd',
        'kwds',
        'keyword',
        'keywords'
    );

    // All other fields are added to description, as "name:value".

    // Only one hide_field is assumed to be present, <> is removed from value.

    if (!($url = trim($linkdata['url'])) || !($title = trim(
            $linkdata['title']
        ))
    ) {
        return 0; // 0 = fail
    }

    $cat = ($catname = trim($linkdata['category'])) ? get_cat($catname) : 0;

    $regs = array(); // Will be passed to ereg()
    foreach ($linkdata as $key => $value) {
        if (!in_array($key, $known_fields)) {
            if (in_array($key, $hide_fields) && ereg(
                    '^<?([^>]*)>?$',
                    $value,
                    $regs
                )
            ) // possibly in <...>
            {
                if (($kwlist = trim($regs[1])) != '') {
                    $kw = '<i kw="' . htmlspecialchars($kwlist) . '">';
                } else {
                    $kw = '';
                }
            } // i.e. assume only one of the $hide_fields will be present
            // and if found, hide the value as expando property of an <i> tag
            elseif (trim($value)) {
                $d .= ', ' . $key . ':' . $value;
            }
        }
    }
    if ($d) {
        $d = substr($d, 2) . ' - ';
    }

    return put_link(
        $url,
        $cat,
        $title,
        $kw . ereg_replace(
            '\[((/?(b|big|i|small|sub|sup|u))|br/)\]',
            '<\\1>',
            htmlspecialchars($d . $linkdata['description'])
        ) . ($kw ? '</i>' : ''),
        $linkdata['on_homepage'] ? '1' : '0',
        $linkdata['hidden'] ? '1' : '0'
    );
    // i.e. allow some BBcode tags, e.g. [b]...[/b]
}

/**
 * CSV file import functions
 * @author René Haentjens , Ghent University
 */
function import_csvfile()
{

    global $catlinkstatus; // Feedback message to user.

    if (is_uploaded_file(
            $filespec = $_FILES['import_file']['tmp_name']
        ) && filesize($filespec) && ($myFile = @ fopen($filespec, 'r'))
    ) {
        // read first line of file (column names) and find ',' or ';'
        $listsep = strpos(
            $colnames = trim(fgets($myFile)),
            ','
        ) !== false ? ',' : (strpos($colnames, ';') !== false ? ';' : '');

        if ($listsep) {
            $columns = array_map('strtolower', explode($listsep, $colnames));

            if (in_array('url', $columns) && in_array('title', $columns)) {
                $stats = array(
                    0,
                    0,
                    0
                ); // fails, updates, inserts

                // Modified by Ivan Tcholakov, 01-FEB-2010.
                //while (($data = fgetcsv($myFile, 32768, $listsep))) {
                while (($data = api_fgetcsv($myFile, null, $listsep))) {
                    //
                    foreach ($data as $i => & $text) {
                        $linkdata[$columns[$i]] = $text;
                    }

                    $stats[import_link($linkdata)]++;
                    unset ($linkdata);
                }

                $catlinkstatus = '';

                if ($stats[0]) {
                    $catlinkstatus .= $stats[0] . ' ' . get_lang(
                            'CsvLinesFailed'
                        );
                }
                if ($stats[1]) {
                    $catlinkstatus .= $stats[1] . ' ' . get_lang('CsvLinesOld');
                }
                if ($stats[2]) {
                    $catlinkstatus .= $stats[2] . ' ' . get_lang('CsvLinesNew');
                }
            } else {
                $catlinkstatus = get_lang(
                        'CsvFileNoURL'
                    ) . ($colnames ? get_lang(
                            'CsvFileLine1'
                        ) . htmlspecialchars(
                            substr($colnames, 0, 200)
                        ) . '...' : '');
            }
        } else {
            $catlinkstatus = get_lang('CsvFileNoSeps') . ($colnames ? get_lang(
                        'CsvFileLine1'
                    ) . htmlspecialchars(
                        substr($colnames, 0, 200)
                    ) . '...' : '');
        }
        fclose($myFile);
    } else {
        $catlinkstatus = get_lang('CsvFileNotFound');
    }
}

/**
 * This function checks if the url is a vimeo link
 * @author Julio Montoya
 * @version 1.0
 */
function isVimeoLink($url)
{
    $isLink = strrpos($url, "vimeo.com");
    return $isLink;
}

function getVimeoLinkId($url)
{
    $possibleUrls = array(
        'http://www.vimeo.com/',
        'http://vimeo.com/',
        'https://www.vimeo.com/',
        'https://vimeo.com/'
    );
    $url = str_replace($possibleUrls, '', $url);

    if (is_numeric($url)) {
        return $url;
    }
    return false;
}

/**
 * This function checks if the url is a youtube link
 * @author Jorge Frisancho
 * @author Julio Montoya - Fixing code
 * @version 1.0
 */
function is_youtube_link($url)
{
    $is_youtube_link = strrpos($url, "youtube") || strrpos($url, "youtu.be");
    return $is_youtube_link;
}

function get_youtube_video_id($url)
{
    // This is the length of YouTube's video IDs
    $len = 11;

    // The ID string starts after "v=", which is usually right after
    // "youtube.com/watch?" in the URL
    $pos = strpos($url, "v=");

    $id = '';

    //If false try other options
    if ($pos === false) {
        $url_parsed = parse_url($url);

        //Youtube shortener
        //http://youtu.be/ID
        $pos = strpos($url, "youtu.be");

        if ($pos == false) {
            $id = '';
        } else {
            return substr($url_parsed['path'], 1);
        }

        //if empty try the youtube.com/embed/ID
        if (empty($id)) {
            $pos = strpos($url, "embed");
            if ($pos === false) {
                return '';
            } else {
                return substr($url_parsed['path'], 7);
            }
        }
    } else {
        // Offset the start location to match the beginning of the ID string
        $pos += 2;
        // Get the ID string and return it
        $id = substr($url, $pos, $len);
        return $id;
    }
}