move url sanitizing function into module

node/routes/preconditions.js

@@ -0,0 +1,28 @@
+module.exports = function(app)
+{
+    //redirects browser to the pad's sanitized url if needed. otherwise, renders the html
+  app.param('pad', function (req, res, next, padId) {
+    //ensure the padname is valid and the url doesn't end with a /
+    if(!app.padManager.isValidPadId(padId) || /\/$/.test(req.url))
+    {
+      res.send('Such a padname is forbidden', 404);
+    }
+    else
+    {
+      app.padManager.sanitizePadId(padId, function(sanitizedPadId) {
+        //the pad id was sanitized, so we redirect to the sanitized version
+        if(sanitizedPadId != padId)
+        {
+          var real_path = req.path.replace(/^\/p\/[^\/]+/, '/p/' + sanitizedPadId);
+          res.header('Location', real_path);
+          res.send('You should be redirected to <a href="' + real_path + '">' + real_path + '</a>', 302);
+        }
+        //the pad id was fine, so just render it
+        else
+        {
+          next();
+        }
+      });
+    }
+  });
+};