Implement page slugs

Closes #3.

help/help.htm

@@ -43,6 +43,12 @@ <h2>Installation</h2>
             <li>Unzip the distribution on your computer.</li>
             <li>Upload the whole directory seo/ to your server into CMSimple_XH's plugins/ directory.</li>
             <li>Set write permissions to the subdirectories config/ und languages/.</li>
+            <li>
+                If you want to use <a href="#usage-slugs">Page Slugs</a>, move userfuncs.php into the cmsimple/
+                folder in the root of the CMSimple_XH installation. If there is already a userfuncs.php, copy
+                the contents of Seo_XH's userfuncs.php into the existing file. Take care to properly handle the
+                PHP start and end tags (&lt;?php and ?&gt;).
+            </li>
             <!--<li>Browse to Pagemanager's administration (Plugins &rarr; Pagemanager), and
 check if all requirements are fulfilled.</li>-->
         </ol>
@@ -101,6 +107,28 @@ <h3>Canonical Links</h3>
                 the configuration option Canonical→Include.
             </p>
         </section>
+        <section id="usage-slugs">
+            <h3>Page Slugs</h3>
+            <p>
+                CMSimple_XH constructs the URLs to access the individual pages from the page
+                headings. This means that any change to the page heading changes the URL of the
+                page, so that existing bookmarks won't work anymore. To avoid that you can keep the
+                old page heading, and set an <a
+                href="http://www.cmsimple-xh.org/wiki/doku.php/pagedata_plugins">Alternative
+                Heading</a> instead, or you can use Moved_XH to cater to such changes.
+            </p>
+            <p>
+                However, Seo_XH offers an alternative solution, so called page slugs. For each page
+                a slug can be entered in the "SEO" tab above the editor. If a slug had been entered
+                it replaces the page URL generated by CMSimple_XH. Page slugs affect only the page
+                for which they are defined, but not subpages.
+            </p>
+            <p>
+                Furthermore, page slugs don't reflect the menu level of the page, and thus can also
+                be used to provide nicely looking short URLs. Anyhow, make sure that the <em>slugs
+                of all pages are unique.</em> Otherwise the navigation won't work as expected.
+            </p>
+        </section>
         <section id="usage-headings">
             <h3>Heading Structure</h3>
             <p>

help/stylesheet.css

@@ -12,7 +12,7 @@ section {
     clear: both;
 }
 
-p {
+p, li {
     text-align: justify;
 }
 

index.php

@@ -8,11 +8,17 @@
 if ($plugin_cf['seo']['canonical_enable']) {
     $hjs .= seo_canonical();
 }
+if (function_exists('seo_slugs')) {
+    $pd_router->add_interest('seo_slug');
+}
 
 if (defined('XH_ADM') && XH_ADM) {
     if (function_exists('XH_registerStandardPluginMenuItems')) {
         XH_registerStandardPluginMenuItems(false);
     }
+    if (function_exists('seo_slugs')) {
+        $pd_router->add_tab($plugin_tx['seo']['label_tab'], $pth['folder']['plugin'] . 'seo_tab.php');
+    }
     if ($edit && $s > -1) {
         if ($plugin_cf['seo']['check_page_headings']) {
             seo_check_heading_structure($l, 1, 'message_page_headings');

languages/en.php

@@ -2,6 +2,9 @@
 
 $plugin_tx['seo']['message_page_headings']="Found irregular page heading structure: %s!";
 $plugin_tx['seo']['message_internal_headings']="Found irregular page internal heading structure: %s!";
+$plugin_tx['seo']['label_save']="Save";
+$plugin_tx['seo']['label_slug']="Slug";
+$plugin_tx['seo']['label_tab']="SEO";
 $plugin_tx['seo']['cf_check_page_headings']="Whether to check the site's page heading structure. In case of an irregular structure, a warning will be shown.";
 $plugin_tx['seo']['cf_check_internal_headings']="Whether to check the current page's internal heading structure. In case of an irregular structure, a warning will be shown.";
 $plugin_tx['seo']['cf_redir_enable']="Whether the other settings in this group are enabled.";

seo_tab.php

@@ -0,0 +1,20 @@
+<?php
+
+function seo_tab($page)
+{
+    global $sn, $su, $plugin_tx;
+
+    $ptx = $plugin_tx['seo'];
+    $action = XH_hsc("$sn?$su");
+    $slug = XH_hsc($page['seo_slug']);
+    return <<<HTML
+<form action="$action" method="post">
+    <label for="seo_slug">{$ptx['label_slug']}</label><br>
+    <input type="text" id="seo_slug" name="seo_slug" size="50" value="$slug">
+    <input type="hidden" name="save_page_data">
+    <div style="text-align: right">
+        <input type="submit" value="{$ptx['label_save']}">
+    </div>
+</form>
+HTML;
+}

userfuncs.php

@@ -0,0 +1,23 @@
+<?php
+
+seo_slugs();
+
+function seo_slugs()
+{
+    global $su, $u, $s, $cl, $pd_router;
+
+    for ($i = 0; $i < $cl; $i++) {
+        $pageData = $pd_router->find_page($i);
+        if (isset($pageData['seo_slug'])) {
+            $slug = trim($pageData['seo_slug']);
+            if ($slug != '') {
+                $u[$i] = $slug;
+                if ($su == $slug) {
+                    $s = $i;
+                } elseif ($i == $s) {
+                    $su = $slug;
+                }
+            }
+        }
+    }
+}