Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Simple moodle database engine.

 *

 * @package    search_simpledb

 * @copyright  2016 David Monllao {@link http://www.davidmonllao.com}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

namespace search_simpledb;

defined('MOODLE_INTERNAL') || die();

/**

 * Simple moodle database engine.

 *

 * @package    search_simpledb

 * @copyright  2016 David Monllao {@link http://www.davidmonllao.com}

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class engine extends \core_search\engine {

    /**

     * Total number of available results.

     *

     * @var null|int

     */

    protected $totalresults = null;

    /**

     * Prepares a SQL query, applies filters and executes it returning its results.

     *

     * @throws \core_search\engine_exception

     * @param  stdClass     $filters Containing query and filters.

     * @param  array        $usercontexts Contexts where the user has access. True if the user can access all contexts.

     * @param  int          $limit The maximum number of results to return.

     * @return \core_search\document[] Results or false if no results

     */

    public function execute_query($filters, $usercontexts, $limit = 0) {

        global $DB, $USER;

        $serverstatus = $this->is_server_ready();

        if ($serverstatus !== true) {

            throw new \core_search\engine_exception('engineserverstatus', 'search');

        }

        if (empty($limit)) {

            $limit = \core_search\manager::MAX_RESULTS;

        }

        $params = array();

        // To store all conditions we will add to where.

        $ands = array();

        // Get results only available for the current user.

        $ands[] = '(owneruserid = ? OR owneruserid = ?)';

        $params = array_merge($params, array(\core_search\manager::NO_OWNER_ID, $USER->id));

        // Restrict it to the context where the user can access, we want this one cached.

        // If the user can access all contexts $usercontexts value is just true, we don't need to filter

        // in that case.

        if ($usercontexts && is_array($usercontexts)) {

            // Join all area contexts into a single array and implode.

            $allcontexts = array();

            foreach ($usercontexts as $areaid => $areacontexts) {

                if (!empty($filters->areaids) && !in_array($areaid, $filters->areaids)) {

                    // Skip unused areas.

                    continue;

                }

                foreach ($areacontexts as $contextid) {

                    // Ensure they are unique.

                    $allcontexts[$contextid] = $contextid;

                }

            }

            if (empty($allcontexts)) {

                // This means there are no valid contexts for them, so they get no results.

                return array();

            }

            list($contextsql, $contextparams) = $DB->get_in_or_equal($allcontexts);

            $ands[] = 'contextid ' . $contextsql;

            $params = array_merge($params, $contextparams);

        }

        // Course id filter.

        if (!empty($filters->courseids)) {

            list($conditionsql, $conditionparams) = $DB->get_in_or_equal($filters->courseids);

            $ands[] = 'courseid ' . $conditionsql;

            $params = array_merge($params, $conditionparams);

        }

        // Area id filter.

        if (!empty($filters->areaids)) {

            list($conditionsql, $conditionparams) = $DB->get_in_or_equal($filters->areaids);

            $ands[] = 'areaid ' . $conditionsql;

            $params = array_merge($params, $conditionparams);

        }

        if (!empty($filters->title)) {

            $ands[] = $DB->sql_like('title', '?', false, false);

            $params[] = $filters->title;

        }

        if (!empty($filters->timestart)) {

            $ands[] = 'modified >= ?';

            $params[] = $filters->timestart;

        }

        if (!empty($filters->timeend)) {

            $ands[] = 'modified <= ?';

            $params[] = $filters->timeend;

        }

        // And finally the main query after applying all AND filters.

        if (!empty($filters->q)) {

            switch ($DB->get_dbfamily()) {

                case 'postgres':

                    $ands[] = "(" .

                        "to_tsvector('simple', title) @@ plainto_tsquery('simple', ?) OR ".

                        "to_tsvector('simple', content) @@ plainto_tsquery('simple', ?) OR ".

                        "to_tsvector('simple', description1) @@ plainto_tsquery('simple', ?) OR ".

                        "to_tsvector('simple', description2) @@ plainto_tsquery('simple', ?)".

                        ")";

                    $params[] = $filters->q;

                    $params[] = $filters->q;

                    $params[] = $filters->q;

                    $params[] = $filters->q;

                    break;

                case 'mysql':

                    if ($DB->is_fulltext_search_supported()) {

                        $ands[] = "MATCH (title, content, description1, description2) AGAINST (?)";

                        $params[] = $filters->q;

                        // Sorry for the hack, but it does not seem that we will have a solution for

                        // this soon (https://bugs.mysql.com/bug.php?id=78485).

                        if ($filters->q === '*') {

                            return array();

                        }

                    } else {

                        // Clumsy version for mysql versions with no fulltext support.

                        list($queryand, $queryparams) = $this->get_simple_query($filters->q);

                        $ands[] = $queryand;

                        $params = array_merge($params, $queryparams);

                    }

                    break;

                case 'mssql':

                    if ($DB->is_fulltext_search_supported()) {

                        $ands[] = "CONTAINS ((title, content, description1, description2), ?)";

                        // Special treatment for double quotes:

                        // - Puntuation is ignored so we can get rid of them.

                        // - Phrases should be enclosed in double quotation marks.

                        $params[] = '"' . str_replace('"', '', $filters->q) . '"';

                    } else {

                        // Clumsy version for mysql versions with no fulltext support.

                        list($queryand, $queryparams) = $this->get_simple_query($filters->q);

                        $ands[] = $queryand;

                        $params = array_merge($params, $queryparams);

                    }

                    break;

                default:

                    list($queryand, $queryparams) = $this->get_simple_query($filters->q);

                    $ands[] = $queryand;

                    $params = array_merge($params, $queryparams);

                    break;

            }

        }

        // It is limited to $limit, no need to use recordsets.

        $documents = $DB->get_records_select('search_simpledb_index', implode(' AND ', $ands), $params, 'docid', '*', 0, $limit);

        // Hopefully database cached results as this applies the same filters than above.

        $this->totalresults = $DB->count_records_select('search_simpledb_index', implode(' AND ', $ands), $params);

        $numgranted = 0;

        // Iterate through the results checking its availability and whether they are available for the user or not.

        $docs = array();

        foreach ($documents as $docdata) {

            if ($docdata->owneruserid != \core_search\manager::NO_OWNER_ID && $docdata->owneruserid != $USER->id) {

                // If owneruserid is set, no other user should be able to access this record.

                continue;

            }

            if (!$searcharea = $this->get_search_area($docdata->areaid)) {

                $this->totalresults--;

                continue;

            }

            // Switch id back to the document id.

            $docdata->id = $docdata->docid;

            unset($docdata->docid);

            $access = $searcharea->check_access($docdata->itemid);

            switch ($access) {

                case \core_search\manager::ACCESS_DELETED:

                    $this->delete_by_id($docdata->id);

                    $this->totalresults--;

                    break;

                case \core_search\manager::ACCESS_DENIED:

                    $this->totalresults--;

                    break;

                case \core_search\manager::ACCESS_GRANTED:

                    $numgranted++;

                    $docs[] = $this->to_document($searcharea, (array)$docdata);

                    break;

            }

            // This should never happen.

            if ($numgranted >= $limit) {

                $docs = array_slice($docs, 0, $limit, true);

                break;

            }

        }

        return $docs;

    }

    /**

     * Adds a document to the search engine.

     *

     * This does not commit to the search engine.

     *

     * @param \core_search\document $document

     * @param bool $fileindexing True if file indexing is to be used

     * @return bool False if the file was skipped or failed, true on success

     */

    public function add_document($document, $fileindexing = false) {

        global $DB;

        $doc = (object)$document->export_for_engine();

        // Moodle's ids using DML are always autoincremented.

        $doc->docid = $doc->id;

        unset($doc->id);

        $id = $DB->get_field('search_simpledb_index', 'id', array('docid' => $doc->docid));

        try {

            if ($id) {

                $doc->id = $id;

                $DB->update_record('search_simpledb_index', $doc);

            } else {

                $DB->insert_record('search_simpledb_index', $doc);

            }

        } catch (\dml_exception $ex) {

            debugging('dml error while trying to insert document with id ' . $doc->docid . ': ' . $ex->getMessage(),

                DEBUG_DEVELOPER);

            return false;

        }

        return true;

    }

    /**

     * Deletes the specified document.

     *

     * @param string $id The document id to delete

     * @return void

     */

    public function delete_by_id($id) {

        global $DB;

        $DB->delete_records('search_simpledb_index', array('docid' => $id));

    }

    /**

     * Delete all area's documents.

     *

     * @param string $areaid

     * @return void

     */

    public function delete($areaid = null) {

        global $DB;

        if ($areaid) {

            $DB->delete_records('search_simpledb_index', array('areaid' => $areaid));

        } else {

            $DB->delete_records('search_simpledb_index');

        }

    }

    /**

     * Checks that the required table was installed.

     *

     * @return true|string Returns true if all good or an error string.

     */

    public function is_server_ready() {

        global $DB;

        if (!$DB->get_manager()->table_exists('search_simpledb_index')) {

            return 'search_simpledb_index table does not exist';

        }

        return true;

    }

    /**

     * It is always installed.

     *

     * @return true

     */

    public function is_installed() {

        return true;

    }

    /**

     * Returns the total results.

     *

     * Including skipped results.

     *

     * @return int

     */

    public function get_query_total_count() {

        if (is_null($this->totalresults)) {

            // This is a just in case as we count total results in execute_query.

            return \core_search\manager::MAX_RESULTS;

        }

        return $this->totalresults;

    }

    /**

     * Returns the default query for db engines.

     *

     * @param string $q The query string

     * @return array SQL string and params list

     */

    protected function get_simple_query($q) {

        global $DB;

        $sql = '(' .

            $DB->sql_like('title', '?', false, false) . ' OR ' .

            $DB->sql_like('content', '?', false, false) . ' OR ' .

            $DB->sql_like('description1', '?', false, false) . ' OR ' .

            $DB->sql_like('description2', '?', false, false) .

            ')';

        // Remove quotes from the query.

        $q = str_replace('"', '', $q);

        $params = [

            '%' . $q . '%',

            '%' . $q . '%',

            '%' . $q . '%',

            '%' . $q . '%'

        ];

        return array($sql, $params);

    }

    /**

     * Simpledb supports deleting the index for a context.

     *

     * @param int $oldcontextid Context that has been deleted

     * @return bool True to indicate that any data was actually deleted

     * @throws \core_search\engine_exception

     */

    public function delete_index_for_context(int $oldcontextid) {

        global $DB;

        try {

            $DB->delete_records('search_simpledb_index', ['contextid' => $oldcontextid]);

        } catch (\dml_exception $e) {

            throw new \core_search\engine_exception('dbupdatefailed');

        }

        return true;

    }

    /**

     * Simpledb supports deleting the index for a course.

     *

     * @param int $oldcourseid

     * @return bool True to indicate that any data was actually deleted

     * @throws \core_search\engine_exception

     */

    public function delete_index_for_course(int $oldcourseid) {

        global $DB;

        try {

            $DB->delete_records('search_simpledb_index', ['courseid' => $oldcourseid]);

        } catch (\dml_exception $e) {

            throw new \core_search\engine_exception('dbupdatefailed');

        }

        return true;

    }

}