Improved template handling with exceptions

The Page class is now responsible for executing the subpage template
rather than the index file.
Template processing has been improved with exceptions to catch 404s, or
any other template exception, which will abort the current page and
display an error document instead.

HandBrakeCluster/Exceptions.class.php

@@ -10,4 +10,8 @@ class HandBrakeCluster_Exception_ResultCountMismatch   extends Exception {};
 
 class HandBrakeCluster_Exception_UnknownSetting        extends Exception {};
 
+class HandBrakeCluster_Exception_TemplateException     extends Exception {};
+class HandBrakeCluster_Exception_Unauthorized          extends HandBrakeCluster_Exception_TemplateException {};
+class HandBrakeCluster_Exception_FileNotFound          extends HandBrakeCluster_Exception_TemplateException {};
+
 ?>

HandBrakeCluster/Main.class.php

@@ -29,7 +29,7 @@ class HandBrakeCluster_Main {
         $this->smarty->config_fir   = './config';
 
         $this->smarty->assign('version', '0.1');
-        $this->smarty->assign('base_uri', '/handbrake/');
+        $this->smarty->assign('base_uri', dirname($_SERVER['SCRIPT_NAME']) . '/');
 
     }
 

HandBrakeCluster/Page.class.php

@@ -18,22 +18,43 @@ class HandBrakeCluster_Page {
     }
 
     public function template_filename() {
-        $template_filename = $this->page . '.tpl';
+        return $this->page . '.tpl';
-
-        if (!$this->smarty->template_exists($template_filename)) {
-            $template_filename = 'home.tpl';
     }
 
-        return $template_filename;
+    public function evaluate($template_variables = array()) {
+        $code_filename     = $this->page . '.php';
+        $template_filename = $this->template_filename();
+
+        try {
+            $this->render($template_filename, $code_filename, $template_variables);
+        } catch (HandBrakeCluster_Exception_FileNotFound $e) {
+            $this->render('errors/404.tpl', 'errors/404.php');
+        } catch (HandBrakeCluster_Exception_TemplateException $e) {
+            $this->render('errors/unhandled-exception.tpl', 'errors/unhandled-exception.php', array(
+                'exception' => $e,
+            ));
+        } 
     }
     
-    public function evaluate() {
+    protected function render($template_filename, $code_filename = null, $template_variables = array()) {
-        $code_filename = 'pages/' . $this->page . '.php';
+        if ( ! $this->smarty->template_exists($template_filename)) {
-
+            throw new HandBrakeCluster_Exception_FileNotFound($template_filename);
-        if (file_exists($code_filename)) {
-            eval("include '$code_filename';");
         }
         
+        // Copy all the template variables into the namespace for this function,
+        // so that they are readily available to the template
+        foreach ($template_variables as $__k => $__v) {
+            $$__k = $__v;
+        }
+        
+        // Include the template code file, which will do all the work for this page
+        $real_code_filename = 'pages/' . $code_filename;
+        if ($code_filename && file_exists($real_code_filename)) {
+            include $real_code_filename;
+        }
+        
+        // Now execute the template itself, which will render the results of the code file
+        $this->smarty->assign('page_content', $this->smarty->fetch($template_filename));
     }
 
 };

HandBrakeCluster/RequestParser.class.php

@@ -43,6 +43,10 @@ class HandBrakeCluster_RequestParser {
         return null;
     }
     
+    public function request_string() {
+        return $this->request_string;
+    }
+
 };
 
 ?>

index.php

@@ -8,8 +8,6 @@ try {
     $page = new HandBrakeCluster_Page($smarty, $main->request());
     $page->evaluate();
     
-    $smarty->assign('page_content', $smarty->fetch($page->template_filename()));
-    
     $smarty->display('index.tpl');
 } catch (HandBrakeCluster_Exception $e) {
     die("Uncaught Exception: " . $e->getMessage());

pages/errors/404.php

@@ -0,0 +1,9 @@
+<?php
+
+$main = HandBrakeCluster_Main::instance();
+$req  = $main->request();
+
+$this->smarty->assign('requested_page', htmlspecialchars($req->request_string()));
+
+
+?>

pages/errors/unhandled-exception.php

@@ -0,0 +1,10 @@
+<?php
+
+$main   = HandBrakeCluster_Main::instance();
+$config = $main->config();
+
+$this->smarty->assign('display_exceptions', $config->get('debug.display_exceptions'));
+$this->smarty->assign('exception', $exception);
+$this->smarty->assign('exception_type', get_class($exception));
+
+?>

templates/errors/404.tpl

@@ -0,0 +1,6 @@
+<h2>The requested page could not be found</h2>
+<p>
+	The file you requested ({$requested_page}) could not be found.
+	If you typed in the address manually, check that you have spelled it correctly,
+	or if you followed a link, let us know and we'll look into it. 
+</p>

templates/errors/unhandled-exception.tpl

@@ -0,0 +1,36 @@
+<h2>An unhandled error has occurred</h2>
+<p>
+	There was a problem trying to complete the requested action. Please try again and if the problem persists, let us know.
+</p>
+
+{if $display_exceptions}
+<p>
+	An unhandled exception was caught during the page template processing. The full details are shown below:
+</p>
+<table class="exception-details">
+	<colgroup id="header">
+		<col />
+	</colgroup>
+	<colgroup>
+		<col />
+	</colgroup>
+	<tbody>
+		<tr>
+			<th>Exception</th>
+			<td>{$exception_type}</td>
+		</tr>
+		<tr>
+			<th>File</th>
+			<td>{$exception->getFile()}</td>
+		</tr>
+		<tr>
+			<th>Line</th>
+			<td>{$exception->getLine()}</td>
+		</tr>
+		<tr>
+			<th>Message</th>
+			<td>{$exception->getMessage()}</td>
+		</tr>
+	</tbody>
+</table>
+{/if}