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vendor/yiisoft/yii2/web/MultiFieldSession.php

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+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\web;
+
+/**
+ * MultiFieldSession is the base class for session storage implementations with multi-field data storage support.
+ *
+ * With multi-field data storage, session data can be split between several fields in the storage record.
+ * Using such a storage allows saving particular session data into separated field, which then can be used
+ * to manipulate sessions in the way plain PHP does not allow.
+ *
+ * For example the ID of the authenticated user can be saved as separated column in the MySQL 'session' table,
+ * which allows to query all active sessions for a particular user or terminate them at will.
+ *
+ * Customizing of the session writing is performed via [[writeCallback]], reading via [[readCallback]].
+ *
+ * While extending this class you should use [[composeFields()]] method - while writing the session data into the storage and
+ * [[extractData()]] - while reading session data from the storage.
+ *
+ * @property bool $useCustomStorage Whether to use custom storage. This property is read-only.
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0.6
+ */
+abstract class MultiFieldSession extends Session
+{
+    /**
+     * @var callable a callback that will be called during session data reading.
+     * The signature of the callback should be as follows:
+     *
+     * ```
+     * function ($fields)
+     * ```
+     *
+     * where `$fields` is the storage field set for read session and `$session` is this session instance.
+     * If callback returns an array, it will be merged into the session data.
+     *
+     * For example:
+     *
+     * ```php
+     * function ($fields) {
+     *     return [
+     *         'expireDate' => Yii::$app->formatter->asDate($fields['expire']),
+     *     ];
+     * }
+     * ```
+     */
+    public $readCallback;
+    /**
+     * @var callable a callback that will be called during session data writing.
+     * The signature of the callback should be as follows:
+     *
+     * ```
+     * function ($session)
+     * ```
+     *
+     * where `$session` is this session instance, this variable can be used to retrieve session data.
+     * Callback should return the actual fields set, which should be saved into the session storage.
+     *
+     * For example:
+     *
+     * ```php
+     * function ($session) {
+     *     return [
+     *         'user_id' => Yii::$app->user->id,
+     *         'ip' => $_SERVER['REMOTE_ADDR'],
+     *         'is_trusted' => $session->get('is_trusted', false),
+     *     ];
+     * }
+     * ```
+     */
+    public $writeCallback;
+
+
+    /**
+     * Returns a value indicating whether to use custom session storage.
+     * This method overrides the parent implementation and always returns true.
+     * @return bool whether to use custom storage.
+     */
+    public function getUseCustomStorage()
+    {
+        return true;
+    }
+
+    /**
+     * Composes storage field set for session writing.
+     * @param string $id session id
+     * @param string $data session data
+     * @return array storage fields
+     */
+    protected function composeFields($id, $data)
+    {
+        $fields = [
+            'data' => $data,
+        ];
+        if ($this->writeCallback !== null) {
+            $fields = array_merge(
+                $fields,
+                call_user_func($this->writeCallback, $this)
+            );
+            if (!is_string($fields['data'])) {
+                $_SESSION = $fields['data'];
+                $fields['data'] = session_encode();
+            }
+        }
+        // ensure 'id' and 'expire' are never affected by [[writeCallback]]
+        $fields = array_merge($fields, [
+            'id' => $id,
+            'expire' => time() + $this->getTimeout(),
+        ]);
+        return $fields;
+    }
+
+    /**
+     * Extracts session data from storage field set.
+     * @param array $fields storage fields.
+     * @return string session data.
+     */
+    protected function extractData($fields)
+    {
+        if ($this->readCallback !== null) {
+            if (!isset($fields['data'])) {
+                $fields['data'] = '';
+            }
+            $extraData = call_user_func($this->readCallback, $fields);
+            if (!empty($extraData)) {
+                session_decode($fields['data']);
+                $_SESSION = array_merge((array) $_SESSION, (array) $extraData);
+                return session_encode();
+            }
+
+            return $fields['data'];
+        }
+
+        return isset($fields['data']) ? $fields['data'] : '';
+    }
+}