From b0ea37ccfddbb2c2e794bae6b0c6b787627b612a Mon Sep 17 00:00:00 2001
From: Sara Golemon <sgolemon@fb.com>
Date: Mon, 5 Aug 2013 15:18:43 -0700
Subject: [PATCH] Implement Redis session module

Translates session events into Redis commands

Differential Revision: D872896
---
 hphp/NEWS                                    |   1 +
 hphp/runtime/ext/ext_session.cpp             |   9 ++
 hphp/system/php.txt                          |   1 +
 hphp/system/php/redis/RedisSessionModule.php | 162 +++++++++++++++++++++++++++
 4 files changed, 173 insertions(+)
 create mode 100644 hphp/system/php/redis/RedisSessionModule.php

diff --git a/hphp/NEWS b/hphp/NEWS
index 909ea841d03..446a5939284 100644
--- a/hphp/NEWS
+++ b/hphp/NEWS
@@ -6,6 +6,7 @@
   - Implement php_strip_whitespace()
   - Support for timeouts in cli mode
   - Closure allocation optimizations (~2x faster to allocate a closure)
+  - Implement Redis session handler
 
 "Tamale" 22-Jul-2013
   - Optimize vector-shaped Arrays (arrays with keys in range 0..size-1)
diff --git a/hphp/runtime/ext/ext_session.cpp b/hphp/runtime/ext/ext_session.cpp
index 1030d37d9d2..8d53c970817 100644
--- a/hphp/runtime/ext/ext_session.cpp
+++ b/hphp/runtime/ext/ext_session.cpp
@@ -532,6 +532,15 @@ bool SystemlibSessionModule::gc(int maxlifetime, int *nrdels) {
 }
 
 //////////////////////////////////////////////////////////////////////////////
+// SystemlibSessionModule implementations
+
+static class RedisSessionModule : public SystemlibSessionModule {
+ public:
+  RedisSessionModule() :
+    SystemlibSessionModule("redis", "RedisSessionModule") { }
+} s_redis_session_module;
+
+//////////////////////////////////////////////////////////////////////////////
 // FileSessionModule
 
 class FileSessionData {
diff --git a/hphp/system/php.txt b/hphp/system/php.txt
index c5de98ce7e6..ec4771d2a66 100644
--- a/hphp/system/php.txt
+++ b/hphp/system/php.txt
@@ -68,6 +68,7 @@ hphp/system/php/lang/ErrorException.php
 hphp/system/php/misc/php_strip_whitespace.php
 hphp/system/php/pdo/PDOException.php
 hphp/system/php/redis/Redis.php
+hphp/system/php/redis/RedisSessionModule.php
 hphp/system/php/reflection/reflection.php
 hphp/system/php/sessions/session_register_shutdown.php
 hphp/system/php/soap/SoapFault.php
diff --git a/hphp/system/php/redis/RedisSessionModule.php b/hphp/system/php/redis/RedisSessionModule.php
new file mode 100644
index 00000000000..5f2e34b2a9d
--- /dev/null
+++ b/hphp/system/php/redis/RedisSessionModule.php
@@ -0,0 +1,162 @@
+<?php
+
+class RedisSessionModule implements SessionHandlerInterface {
+  /**
+   * Total of all connection weights, used as divisor in key distribution
+   */
+  protected $weight = 0;
+
+  /**
+   * Map of redis backend servers to use
+   *
+   * Comes from session.save_path which is a comma delimted list of URIs
+   * in the form of:
+   *
+   *   proto://hostOrPath:optionalPort?key=val&key=val...
+   *
+   * Where proto is one of: tcp | unix
+   *
+   * When proto is 'tcp' and no port is given, Redis::DEFAULT_PORT is assumed
+   *
+   * Key/Value pairs are as follows:
+   *  weight(int) - Likelihood of using this backend will be $weight/$total
+   *  timeout(int) - Connection timeout in seconds
+   *  persistent(int) - 0 or 1 for non-persistent or persistent connections
+   *  prefix(string) - String prefix to apply to all session keys in the DB
+   *  auth(string) - Password used to authenticate to the DB
+   *  database(int) - Database shard to use
+   *
+   * Defaults can be found in the code below
+   */
+  protected $paths = [];
+
+  public function open($save_path, $session_name) {
+    $this->weight = 0;
+    $this->paths  = [];
+
+    $paths = preg_split('/[\s,]+/', $save_path, -1, PREG_SPLIT_NO_EMPTY);
+    foreach ($paths as $path) {
+      if (!strncmp($path, "unix:", 5)) {
+        $path = 'file:' . substr($path, 5);
+      }
+      $url = parse_url($path);
+      $args = [
+        'weight' => 1,
+        'timeout' => 86400,
+        'persistent' => 0,
+        'prefix' => 'PHPREDIS_SESSION:',
+        'auth' => '',
+        'database' => 0
+      ];
+      if (isset($url['query'])) {
+        parse_str($url['query'], $query);
+        foreach ($args as $key => &$val) {
+          if (!isset($query[$key])) continue;
+          if (is_string($val)) {
+            $val = $query[$key];
+          } else {
+            $val = (int)$query[$key];
+          }
+        }
+      }
+
+      if ($args['weight'] === 0) {
+        // Disabled target, skip
+        continue;
+      }
+      if ($args['weight'] < 1) {
+        error_log("Invalid weight specified for session.save_path(redis), ".
+                  "assuming 1", E_USER_WARNING);
+        $args['weight'] = 1;
+      }
+
+      if ($url['scheme'] == 'file') {
+        $args['host'] = "unix://{$url['path']}";
+        $args['port'] = null;
+      } else {
+        $args['host'] = $url['host'];
+        $args['port'] = !empty($url['port'])
+                      ? $url['port'] : Redis::DEFAULT_PORT;
+      }
+
+      $args['connection'] = null;
+
+      $this->weight += $args['weight'];
+      $this->paths[] = $args;
+    }
+
+    return true;
+  }
+
+  protected function &selectWeight($key) {
+    if (count($this->paths) === 1) {
+      return $this->paths[0];
+    }
+    $pos  = abs(unpack("I", $key));
+    $pos %= $this->weight;
+    foreach ($this->paths as $path) {
+      $pos -= $path['weight'];
+      if ($pos <= 0) {
+        return $path;
+      }
+    }
+
+    throw new RedisException("Ran out of weights selecting redis host ".
+                             "for session: $key");
+  }
+
+  protected function connect($key) {
+    $r =& $this->selectWeight($key);
+    if (!empty($r['connection'])) {
+      return $r['connection'];
+    }
+
+    $redis = new Redis;
+    $func = ($r['persistent']) ? 'pconnect' : 'connect';
+    if (!$redis->{$func}($r['host'], $r['port'], $r['timeout'])) {
+      return false;
+    }
+    if (($r['auth'] !== '') &&
+        !$redis->auth($r['auth'])) {
+      return false;
+    }
+    if (($r['database'] !== 0) &&
+        !$redis->select($r['database'])) {
+      return false;
+    }
+    if (!$redis->setOption(Redis::OPT_PREFIX, $r['prefix'])) {
+      return false;
+    }
+
+    $r['connection'] = $redis;
+    return $redis;
+  }
+
+  public function close() {
+    foreach ($this->paths as &$path) {
+      $path['connection'] = null;
+    }
+
+    return true;
+  }
+
+  public function read($key) {
+    $redis = $this->connect($key);
+    return (string)$redis->get($key);
+  }
+
+  public function write($key, $value) {
+    $redis = $this->connect($key);
+    return $redis->set($key, $value, ini_get('session.gc_maxlifetime'));
+  }
+
+  public function destroy($key) {
+    $redis = $this->connect($key);
+    return $redis->del($key);
+  }
+
+  public function gc($maxlifetime) {
+    // Handled by $redis->set(..., ini_get('session.gc_maxlifetime'))
+    return 0;
+  }
+}
-- 
2.11.4.GIT