From 367e7440be935fc95eb4b31a0b534b36b0b791df Mon Sep 17 00:00:00 2001
From: Kijin Sung <kijin@kijinsung.com>
Date: Fri, 5 Mar 2021 13:56:35 +0900
Subject: [PATCH] Don't overwrite OpenGraph tags already set by user

---
 classes/context/Context.class.php      |  1 +
 classes/display/HTMLDisplayHandler.php | 62 ++++++++++++++++----------
 2 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/classes/context/Context.class.php b/classes/context/Context.class.php
index 4a9730a55..f2aced118 100644
--- a/classes/context/Context.class.php
+++ b/classes/context/Context.class.php
@@ -2764,6 +2764,7 @@ class Context
 	public static function setCanonicalURL($url)
 	{
 		self::$_instance->canonical_url = escape($url, false);
+		self::addOpenGraphData('og:url', self::$_instance->canonical_url);
 	}
 	
 	/**
diff --git a/classes/display/HTMLDisplayHandler.php b/classes/display/HTMLDisplayHandler.php
index ff831d1d1..df5b9f261 100644
--- a/classes/display/HTMLDisplayHandler.php
+++ b/classes/display/HTMLDisplayHandler.php
@@ -457,40 +457,56 @@ class HTMLDisplayHandler
 			}
 		}
 		
+		// Get existing metadata.
+		$og_data = array();
+		foreach (Context::getOpenGraphData() as $val)
+		{
+			$og_data[$val['property']] = $val['content'];
+		}
+		
 		// Add basic metadata.
 		Context::addOpenGraphData('og:title', $permitted ? Context::getBrowserTitle() : lang('msg_not_permitted'));
 		Context::addOpenGraphData('og:site_name', Context::getSiteTitle());
-		if ($page_type === 'article' && $permitted && config('seo.og_extract_description'))
+		if (!isset($og_data['og:description']) || !Context::getMetaTag('description'))
 		{
-			$description = trim(utf8_normalize_spaces($oDocument->getContentText(200)));
+			if ($page_type === 'article' && $permitted && config('seo.og_extract_description'))
+			{
+				$description = trim(utf8_normalize_spaces($oDocument->getContentText(200)));
+			}
+			else
+			{
+				$description = Context::getMetaTag('description');
+			}
+			Context::addOpenGraphData('og:description', $description);
+			Context::addMetaTag('description', $description);
 		}
-		else
-		{
-			$description = Context::getMetaTag('description');
-		}
-		Context::addOpenGraphData('og:description', $description);
-		Context::addMetaTag('description', $description);
 		
 		// Add metadata about this page.
-		Context::addOpenGraphData('og:type', $page_type);
-		if ($page_type === 'article')
+		if (!isset($og_data['og:type']))
 		{
-			$canonical_url = getFullUrl('', 'mid', $current_module_info->mid, 'document_srl', $document_srl);
+			Context::addOpenGraphData('og:type', $page_type);
 		}
-		elseif (($page = Context::get('page')) > 1)
+		if (!isset($og_data['og:url']) || !Context::getCanonicalURL())
 		{
-			$canonical_url = getFullUrl('', 'mid', $current_module_info->mid, 'page', $page);
+			if ($page_type === 'article')
+			{
+				$canonical_url = getFullUrl('', 'mid', $current_module_info->mid, 'document_srl', $document_srl);
+			}
+			elseif (($page = Context::get('page')) > 1)
+			{
+				$canonical_url = getFullUrl('', 'mid', $current_module_info->mid, 'page', $page);
+			}
+			elseif ($current_module_info->module_srl == $site_module_info->module_srl)
+			{
+				$canonical_url = getFullUrl('');
+			}
+			else
+			{
+				$canonical_url = getFullUrl('', 'mid', $current_module_info->mid);
+			}
+			Context::addOpenGraphData('og:url', $canonical_url);
+			Context::setCanonicalURL($canonical_url);
 		}
-		elseif ($current_module_info->module_srl == $site_module_info->module_srl)
-		{
-			$canonical_url = getFullUrl('');
-		}
-		else
-		{
-			$canonical_url = getFullUrl('', 'mid', $current_module_info->mid);
-		}
-		Context::addOpenGraphData('og:url', $canonical_url);
-		Context::setCanonicalURL($canonical_url);
 		
 		// Add metadata about the locale.
 		$lang_type = Context::getLangType();