From b4dec2a99cbf01dc77ed9c6ec5041a9d8214b332 Mon Sep 17 00:00:00 2001
From: Dan Brown <ssddanbrown@googlemail.com>
Date: Sun, 21 Feb 2016 11:29:46 +0000
Subject: [PATCH] Made page anchor hashes more relevant to the page content

This will help when adding support for new kinds of page content such as markdown as we won't be able to reference the same ID's as before thus they would break on every save.
---
 app/Repos/PageRepo.php | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/app/Repos/PageRepo.php b/app/Repos/PageRepo.php
index 1acf3c847..0c6f4a256 100644
--- a/app/Repos/PageRepo.php
+++ b/app/Repos/PageRepo.php
@@ -132,14 +132,13 @@ class PageRepo
         $childNodes = $body->childNodes;
 
         // Ensure no duplicate ids are used
-        $lastId = false;
         $idArray = [];
 
         foreach ($childNodes as $index => $childNode) {
             /** @var \DOMElement $childNode */
             if (get_class($childNode) !== 'DOMElement') continue;
 
-            // Overwrite id if not a bookstack custom id
+            // Overwrite id if not a BookStack custom id
             if ($childNode->hasAttribute('id')) {
                 $id = $childNode->getAttribute('id');
                 if (strpos($id, 'bkmrk') === 0 && array_search($id, $idArray) === false) {
@@ -149,13 +148,18 @@ class PageRepo
             }
 
             // Create an unique id for the element
-            do {
-                $id = 'bkmrk-' . substr(uniqid(), -5);
-            } while ($id == $lastId);
-            $lastId = $id;
+            // Uses the content as a basis to ensure output is the same every time
+            // the same content is passed through.
+            $contentId = 'bkmrk-' . substr(strtolower(preg_replace('/\s+/', '-', trim($childNode->nodeValue))), 0, 20);
+            $newId = urlencode($contentId);
+            $loopIndex = 0;
+            while (in_array($newId, $idArray)) {
+                $newId = urlencode($contentId . '-' . $loopIndex);
+                $loopIndex++;
+            }
 
-            $childNode->setAttribute('id', $id);
-            $idArray[] = $id;
+            $childNode->setAttribute('id', $newId);
+            $idArray[] = $newId;
         }
 
         // Generate inner html as a string