CachedPage: move to a proper file, add tests

Modifications
 - rename `pageCache` to `CachedPage`
 - move utilities to `Cache`
 - do not access globals
 - apply coding rules
 - update LinkDB and test code
 - add test coverage

Signed-off-by: VirtualTam <virtualtam@flibidi.net>

1 files changed, 63 insertions, 0 deletions

diff --git a/application/CachedPage.php b/application/CachedPage.php
new file mode 100644
index 00000000..50cfa9ac
--- /dev/null
+++ b/application/CachedPage.php
@@ -0,0 +1,63 @@
+<?php
+/**
+ * Simple cache system, mainly for the RSS/ATOM feeds
+ */
+class CachedPage
+{
+    // Directory containing page caches
+    private $cacheDir;
+
+    // Full URL of the page to cache -typically the value returned by pageUrl()
+    private $url;
+
+    // Should this URL be cached (boolean)?
+    private $shouldBeCached;
+
+    // Name of the cache file for this URL
+    private $filename;
+
+    /**
+     * Creates a new CachedPage
+     *
+     * @param string $cacheDir       page cache directory
+     * @param string $url            page URL
+     * @param bool   $shouldBeCached whether this page needs to be cached
+     */
+    public function __construct($cacheDir, $url, $shouldBeCached)
+    {
+        // TODO: check write access to the cache directory
+        $this->cacheDir = $cacheDir;
+        $this->url = $url;
+        $this->filename = $this->cacheDir.'/'.sha1($url).'.cache';
+        $this->shouldBeCached = $shouldBeCached;
+    }
+
+    /**
+     * Returns the cached version of a page, if it exists and should be cached
+     *
+     * @return a cached version of the page if it exists, null otherwise
+     */
+    public function cachedVersion()
+    {
+        if (!$this->shouldBeCached) {
+            return null;
+        }
+        if (is_file($this->filename)) {
+            return file_get_contents($this->filename);
+        }
+        return null;
+    }
+
+    /**
+     * Puts a page in the cache
+     *
+     * @param string $pageContent XML content to cache
+     */
+    public function cache($pageContent)
+    {
+        if (!$this->shouldBeCached) {
+            return;
+        }
+        file_put_contents($this->filename, $pageContent);
+    }
+}