prepare to test fast track cache

CFastTrackCache.php

@@ -0,0 +1,231 @@
+<?php
+/**
+ * Enable a fast track cache with a json representation of the image delivery.
+ *
+ */
+class CFastTrackCache
+{
+    /**
+     * Cache is disabled to start with.
+     */
+    private $enabled = false;
+
+
+
+    /**
+     * Path to the cache directory.
+     */
+    private $path;
+
+
+
+    /**
+     * Filename of current cache item.
+     */
+    private $filename;
+
+
+
+    /**
+     * Container with items to store as cached item.
+     */
+    private $container;
+
+
+
+    /**
+     * Enable or disable cache.
+     *
+     * @param boolean $enable set to true to enable, false to disable
+     *
+     * @return $this
+     */
+    public function enable($enabled)
+    {
+        $this->enabled = $enabled;
+        return $this;
+    }
+
+
+
+    /**
+     * Set the path to the cache dir which must exist.
+     *
+     * @param string $path to the cache dir.
+     *
+     * @throws Exception when $path is not a directory.
+     *
+     * @return $this
+     */
+    public function setCacheDir($path)
+    {
+        if (!is_dir($path)) {
+            throw new Exception("Cachedir is not a directory.");
+        }
+
+        $this->path = rtrim($path, "/");
+
+        return $this;
+    }
+
+
+
+    /**
+     * Set the filename to store in cache, use the querystring to create that
+     * filename.
+     *
+     * @param array $clear items to clear in $_GET when creating the filename.
+     *
+     * @return string as filename created.
+     */
+    public function setFilename($clear)
+    {
+        $query = $_GET;
+
+        // Remove parts from querystring that should not be part of filename
+        foreach ($clear as $value) {
+            unset($query[$value]);
+        }
+
+        arsort($query);
+        $queryAsString = http_build_query($query);
+
+        $this->filename = md5($queryAsString);
+        $this->container["query-string"] = $queryAsString;
+
+        return $this->filename;
+    }
+
+
+
+    /**
+     * Add header items.
+     *
+     * @param string $header add this as header.
+     *
+     * @return $this
+     */
+    public function addHeader($header)
+    {
+        $this->container["header"][] = $header;
+        return $this;
+    }
+
+
+
+    /**
+     * Add header items on output, these are not output when 304.
+     *
+     * @param string $header add this as header.
+     *
+     * @return $this
+     */
+    public function addHeaderOnOutput($header)
+    {
+        $this->container["header-output"][] = $header;
+        return $this;
+    }
+
+
+
+    /**
+     * Set path to source image to.
+     *
+     * @param string $source path to source image file.
+     *
+     * @return $this
+     */
+    public function setSource($source)
+    {
+        $this->container["source"] = $source;
+        return $this;
+    }
+
+
+
+    /**
+     * Set last modified of source image, use to check for 304.
+     *
+     * @param string $lastModified
+     *
+     * @return $this
+     */
+    public function setLastModified($lastModified)
+    {
+        $this->container["last-modified"] = $lastModified;
+        return $this;
+    }
+
+
+
+    /**
+     * Get filename of cached item.
+     *
+     * @return string as filename.
+     */
+    public function getFilename()
+    {
+        return $this->path . "/" . $this->filename;
+    }
+
+
+
+    /**
+     * Write current item to cache.
+     *
+     * @return boolean if cache file was written.
+     */
+    public function writeToCache()
+    {
+        if (!$this->enabled) {
+            return false;
+        }
+
+        if (is_dir($this->path) && is_writable($this->path)) {
+            $filename = $this->getFilename();
+            return file_put_contents($filename, json_encode($this->container)) !== false;
+        }
+
+        return false;
+    }
+
+
+
+    /**
+     * Output current item from cache, if available.
+     *
+     * @return void
+     */
+    public function output()
+    {
+        $filename = $this->getFilename();
+        if (!is_readable($filename)) {
+            return;
+        }
+
+        $item = json_decode(file_get_contents($filename), true);
+
+        if (!is_readable($item["source"])) {
+            return;
+        }
+
+        foreach ($item["header"] as $value) {
+            header($value);
+        }
+
+        if (isset($_SERVER["HTTP_IF_MODIFIED_SINCE"])
+            && strtotime($_SERVER["HTTP_IF_MODIFIED_SINCE"]) == $item["last-modified"]) {
+            header("HTTP/1.0 304 Not Modified");
+            debug("fast track 304");
+            exit;
+        }
+
+        foreach ($item["header-output"] as $value) {
+            header($value);
+        }
+
+        readfile($item["source"]);
+        debug("fast track 200");
+        exit;
+    }
+}