If a non-existent page is requested, but a namespace with that name exists, and it has a start page, you will be redirected to it. I think the autosearch plugin does this, but I haven't been able to obtain it.

Create a directory autostart in /wiki/lib/plugins and save the code in a action.php file there.

action.php

<?php
/**
 * Autostart Plugin: Redirects to the namespace's start page if available
 *
 * @author Jesús A. Álvarez <zydeco@namedfork.net>
 */
 
if (!defined('DOKU_INC')) die();
if (!defined('DOKU_PLUGIN')) define('DOKU_PLUGIN', DOKU_INC . 'lib/plugins/');
require_once (DOKU_PLUGIN . 'action.php');
 
class action_plugin_autostart extends DokuWiki_Action_Plugin
{
    function getInfo() {
        return array (
            'author' => 'Jesús A. Álvarez',
            'email' => 'zydeco@namedfork.net',
            'date' => '2008-04-28',
            'name' => 'Autostart Plugin',
            'desc' => "Redirect from the namespace's name to its start page",
            'url' => 'http://www.dokuwiki.org/plugin:autostart',
        );
    }
 
    function page_exists($id) {
        if (function_exists('page_exists'))
            return page_exists($id);
        else
            return @file_exists(wikiFN($id));
    }
 
    function register(Doku_Event_Handler $controller) {
        $controller->register_hook('ACTION_ACT_PREPROCESS', 'AFTER', $this, 'preprocess', array ());
    }
 
    function preprocess(& $event, $param) {
        global $conf;
        global $ID;
        if (!$this->page_exists($ID) && $event->data == 'show')
        {
            if($this->page_exists($ID.':'.$conf['start']))
                // start page inside namespace
                $id = $ID.':'.$conf['start'];
            elseif($this->page_exists($ID.':'.noNS(cleanID($ID))))
                // page named like the NS inside the NS
                $id = $ID.':'.noNS(cleanID($ID));
            if ($id) header('Location: ' . wl($id,'',true));
        }
    }
 
}

Nice work! Thanks! - Jason Xun Xu jasonxu [dot] dev [at] gmail [dot] com

Very handy plugin, great work! By the way: redirecting into a namespace (e.g. foobar → foobar:start) only works if the user/group has at least read permissions for the underlying/root namespace. In certain setups, e.g. one namespace per customer, this can be very tedious to securely implement. By removing a condition for the HTTP redirect this works out and permissions are checked on the target page anyway.

--- lib/plugins/autostart/action.php.orig       2009-11-24 20:41:31.000000000 +0100
+++ lib/plugins/autostart/action.php    2009-11-24 20:42:58.000000000 +0100
@@ -36,7 +36,7 @@
     function preprocess(& $event, $param) {
         global $conf;
         global $ID;
-        if (!$this->page_exists($ID) && $event->data == 'show')
+        if (!$this->page_exists($ID))
         {
             if($this->page_exists($ID.':'.$conf['start']))
                 // start page inside namespace

Andreas de Pretis ad [at] 25th [dash] floor [dot] com

Thanks, I'm using the plugin with Andreas' patch on 2013-05-10a “Weatherwax” with no issues. — Justin K 2013-09-24