MDL-68500 dataformat: re-factor download/export methods into new class.

2020-05-04 16:01:12 +01:00
parent 1de3b81983
commit 8844cb8286
8 changed files with 169 additions and 141 deletions
@@ -0,0 +1,151 @@
+<?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/>.
+
+/**
+ * Class containing utility methods for dataformats
+ *
+ * @package     core
+ * @copyright   2020 Moodle Pty Ltd <[email protected]>
+ * @author      2020 Paul Holden <[email protected]>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @license     Moodle Workplace License, distribution is restricted, contact [email protected]
+ */
+
+namespace core;
+
+use coding_exception;
+use core_php_time_limit;
+
+/**
+ * Dataformat utility class
+ *
+ * @package     core
+ * @copyright   2020 Moodle Pty Ltd <[email protected]>
+ * @author      2020 Paul Holden <[email protected]>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @license     Moodle Workplace License, distribution is restricted, contact [email protected]
+ */
+class dataformat {
+
+    /**
+     * Return an instead of a dataformat writer from given dataformat type
+     *
+     * @param string $dataformat
+     * @return dataformat\base
+     * @throws coding_exception
+     */
+    protected static function get_format_instance(string $dataformat): \core\dataformat\base {
+        $classname = 'dataformat_' . $dataformat . '\writer';
+        if (!class_exists($classname)) {
+            throw new coding_exception('Invalid dataformat', $dataformat);
+        }
+
+        return new $classname();
+    }
+
+    /**
+     * Sends a formatted data file to the browser
+     *
+     * @param string $filename
+     * @param string $dataformat
+     * @param array $columns
+     * @param Iterable $iterator
+     * @param callable|null $callback
+     * @throws coding_exception
+     */
+    public static function download_data(string $filename, string $dataformat, array $columns, Iterable $iterator,
+            callable $callback = null): void {
+
+        if (ob_get_length()) {
+            throw new coding_exception('Output can not be buffered before calling download_data()');
+        }
+
+        $format = self::get_format_instance($dataformat);
+
+        // The data format export could take a while to generate.
+        core_php_time_limit::raise();
+
+        // Close the session so that the users other tabs in the same session are not blocked.
+        \core\session\manager::write_close();
+
+        // If this file was requested from a form, then mark download as complete (before sending headers).
+        \core_form\util::form_download_complete();
+
+        $format->set_filename($filename);
+        $format->send_http_headers();
+
+        $format->start_output();
+        $format->start_sheet($columns);
+
+        $rownum = 0;
+        foreach ($iterator as $row) {
+            if (is_callable($callback)) {
+                $row = $callback($row);
+            }
+            if ($row === null) {
+                continue;
+            }
+            $format->write_record($row, $rownum++);
+        }
+
+        $format->close_sheet($columns);
+        $format->close_output();
+    }
+
+    /**
+     * Writes a formatted data file with specified filename
+     *
+     * @param string $filename
+     * @param string $dataformat
+     * @param array $columns
+     * @param Iterable $iterator
+     * @param callable|null $callback
+     * @return string Complete path to the file on disk
+     */
+    public static function write_data(string $filename, string $dataformat, array $columns, Iterable $iterator,
+            callable $callback = null): string {
+
+        $format = self::get_format_instance($dataformat);
+
+        // The data format export could take a while to generate.
+        core_php_time_limit::raise();
+
+        // Close the session so that the users other tabs in the same session are not blocked.
+        \core\session\manager::write_close();
+
+        $filepath = make_request_directory() . '/' . $filename . $format->get_extension();
+        $format->set_filepath($filepath);
+
+        $format->start_output_to_file();
+        $format->start_sheet($columns);
+
+        $rownum = 0;
+        foreach ($iterator as $row) {
+            if (is_callable($callback)) {
+                $row = $callback($row);
+            }
+            if ($row === null) {
+                continue;
+            }
+            $format->write_record($row, $rownum++);
+        }
+
+        $format->close_sheet($columns);
+        $format->close_output_to_file();
+
+        return $filepath;
+    }
+}