Tweak the cache implementation

1) Drop the *_modified key, we don't really need it.  The modification date is not
   relevant to our browser caching strategy.
2) Fix multiple issues with the Expires header and just hardcode it to the biggest
   possibly value for code clarity.
3) print the $content out directly instead of using fwrite
4) Minor cleanups in the installer.

3 files changed, 33 insertions, 36 deletions

diff --git a/modules/gallery/controllers/javascript.php b/modules/gallery/controllers/javascript.php
index bc231e0a..ba5cbf4b 100644
--- a/modules/gallery/controllers/javascript.php
+++ b/modules/gallery/controllers/javascript.php
@@ -27,16 +27,13 @@ class Javascript_Controller extends Controller {
     // We don't need to save the session for this request
     Session::abort_save();
 
-    // Dump out the javascript file
-    $cache = Cache::instance();
-
-    $modified = $cache->get("{$key}_modified");
-    if (!empty($_SERVER["HTTP_IF_MODIFIED_SINCE"]) && !empty($modified)) {
+    // Our data is immutable, so if they already have a copy then it needs no updating.
+    if (!empty($_SERVER["HTTP_IF_MODIFIED_SINCE"])) {
       header('HTTP/1.0 304 Not Modified');
       return;
     }
 
-    $content = "";
+    $cache = Cache::instance();
     if (strpos($_SERVER["HTTP_ACCEPT_ENCODING"], "gzip") !== false ) {
       $content = $cache->get("{$key}_gz");
     }
@@ -51,19 +48,15 @@ class Javascript_Controller extends Controller {
 
     if (strpos($_SERVER["HTTP_ACCEPT_ENCODING"], "gzip") !== false) {
       header("Content-Encoding: gzip");
-      header("Cache-Control: private, x-gzip-ok=\"public\"");
+      header("Cache-Control: public");
     }
 
     header("Content-Type: text/javascript; charset=UTF-8");
-
-    header("Expires: " . gmdate(21474383647));
-    header("Last-Modified: " . $modified);
+    header("Expires: Tue, 19 Jan 2038 00:00:00 GMT");
+    header("Last-Modified: " . gmdate("D, d M Y H:i:s T", time()));
 
     Kohana::close_buffers(false);
-
-    $handle = fopen("php://output", "wb");
-    fwrite($handle, $content);
-    fclose($handle);
+    print $content;
   }
 }
 
diff --git a/modules/gallery/helpers/gallery_installer.php b/modules/gallery/helpers/gallery_installer.php
index 8ccbd51b..d0bfa629 100644
--- a/modules/gallery/helpers/gallery_installer.php
+++ b/modules/gallery/helpers/gallery_installer.php
@@ -32,6 +32,15 @@ class gallery_installer {
                  PRIMARY KEY (`id`))
                ENGINE=InnoDB DEFAULT CHARSET=utf8;");
 
+    $db->query("CREATE TABLE {caches} (
+                `id` varchar(255) NOT NULL,
+                `tags` varchar(255),
+                `expiration` int(9) NOT NULL,
+                `cache` longblob,
+                PRIMARY KEY (`id`),
+                KEY (`tags`))
+                ENGINE=InnoDB DEFAULT CHARSET=utf8;");
+
     $db->query("CREATE TABLE {graphics_rules} (
                  `id` int(9) NOT NULL auto_increment,
                  `active` BOOLEAN default 0,
@@ -181,15 +190,6 @@ class gallery_installer {
                 UNIQUE KEY(`module_name`, `name`))
                ENGINE=InnoDB DEFAULT CHARSET=utf8;");
 
-    $db->query("CREATE TABLE {caches} (
-                `id` varchar(255) NOT NULL,
-                `tags` varchar(255),
-                `expiration` int(9) NOT NULL,
-                `cache` longblob,
-                PRIMARY KEY (`id`),
-                KEY (`tags`))
-                ENGINE=InnoDB DEFAULT CHARSET=utf8;");
-
     foreach (array("albums", "logs", "modules", "resizes", "thumbs", "tmp", "uploads") as $dir) {
       @mkdir(VARPATH . $dir);
     }
@@ -278,13 +278,13 @@ class gallery_installer {
 
     if ($version == 3) {
       $db->query("CREATE TABLE {caches} (
-                `id` varchar(255) NOT NULL,
-                `tags` varchar(255),
-                `expiration` int(9) NOT NULL,
-                `cache` text,
-                PRIMARY KEY (`id`),
-                KEY (`tags`))
-                ENGINE=InnoDB DEFAULT CHARSET=utf8;");
+                 `id` varchar(255) NOT NULL,
+                 `tags` varchar(255),
+                 `expiration` int(9) NOT NULL,
+                 `cache` text,
+                 PRIMARY KEY (`id`),
+                 KEY (`tags`))
+                 ENGINE=InnoDB DEFAULT CHARSET=utf8;");
       module::set_version("gallery", $version = 4);
     }
     if ($version == 4) {
diff --git a/modules/gallery/libraries/Theme_View.php b/modules/gallery/libraries/Theme_View.php
index f55cb55a..c3acfeb3 100644
--- a/modules/gallery/libraries/Theme_View.php
+++ b/modules/gallery/libraries/Theme_View.php
@@ -172,6 +172,10 @@ class Theme_View_Core extends View {
     $this->scripts[$file] = 1;
   }
 
+  /**
+   * Combine a series of Javascript files into a single one and cache it in the database, then
+   * return a single <script> element to refer to it.
+   */
   private function _combine_script() {
     $links = array();
     $key = "";
@@ -188,18 +192,18 @@ class Theme_View_Core extends View {
     }
 
     $key = md5($key);
-    $contents = Cache::instance()->get($key);
+    $cache = Cache::instance();
+    $contents = $cache->get($key);
     if (empty($contents)) {
-      $contents = '';
+      $contents = "";
       foreach ($links as $link) {
         $contents .= file_get_contents($link);
       }
-      Cache::instance()->set($key, $contents, array("javascript"), 84600);
+      $cache->set($key, $contents, array("javascript"), 30 * 84600);
       if (function_exists("gzencode")) {
-        Cache::instance()->set("{$key}_gz", gzencode($contents, 9, FORCE_GZIP),
-                               array("javascript", "gzip"), 84600);
+        $cache->set("{$key}_gz", gzencode($contents, 9, FORCE_GZIP),
+                    array("javascript", "gzip"), 30 * 84600);
       }
-      Cache::instance()->set("{$key}_modified", time(), array("javascript", "modified"), 84600);
     }
 
     // Handcraft the script link because html::script will add a .js extenstion