allow changing the top-left logo link target in system config

Signed-off-by: Julien Veyssier <eneiluj@posteo.net>

config/config.sample.php

@@ -353,6 +353,13 @@ $CONFIG = [
  */
 'lost_password_link' => 'https://example.org/link/to/password/reset',
 
+/**
+ * URL to use as target for the logo link in the header (top-left logo)
+ *
+ * Defaults to the base URL of your Nextcloud instance
+ */
+'logo_url' => 'https://example.org',
+
 /**
  * Mail Parameters
  *

core/templates/layout.user.php

@@ -56,7 +56,7 @@ $getUserAvatar = static function (int $size) use ($_): string {
 		</div>
 		<header role="banner" id="header">
 			<div class="header-left">
-				<a href="<?php print_unescaped(link_to('', 'index.php')); ?>"
+				<a href="<?php print_unescaped($_['logoUrl'] ?: link_to('', 'index.php')); ?>"
 					id="nextcloud">
 					<div class="logo logo-icon">
 						<h1 class="hidden-visually">

lib/private/TemplateLayout.php

@@ -98,6 +98,10 @@ class TemplateLayout extends \OC_Template {
 			$this->initialState->provideInitialState('unified-search', 'limit-default', SearchQuery::LIMIT_DEFAULT);
 			Util::addScript('core', 'unified-search', 'core');
 
+			// set logo link target
+			$logoUrl = $this->config->getSystemValueString('logo_url', '');
+			$this->assign('logoUrl', $logoUrl);
+
 			// Add navigation entry
 			$this->assign('application', '');
 			$this->assign('appid', $appId);