fixes #2557 use pwg_get_cookie_var

-Update cookie to use pwg_lang to avoid conflicts with other potential apps.
-Add cookie path to the pwg_lang cookie to help with conflicts also.
-Be less restrictive in load_cookie_language function
-We can't use pwg_set_cookie because it is set in js not PHP so we force it to be called pwg_lang

identification.php

@@ -135,7 +135,8 @@ foreach (get_languages() as $language_code => $language_name)
 
 $template->assign(array(
   'language_options' => $language_options,
-  'current_language' => $user['language']
+  'current_language' => $user['language'],
+  'COOKIE_PATH' => cookie_path(),
 ));
 
 //Get link to doc

include/functions.inc.php

@@ -1942,21 +1942,17 @@ function load_cookie_language($load_language=true, $update_user=false, $unset_co
   global $user;
 
   // Load language if cookie is set from login/register/password pages
-  if (isset($_COOKIE['lang']) and $user['language'] != $_COOKIE['lang'])
+  if (pwg_get_cookie_var('lang') and array_key_exists(pwg_get_cookie_var('lang'), get_languages()))
   {
-    if (!array_key_exists($_COOKIE['lang'], get_languages()))
-    {
-      fatal_error('[Hacking attempt] the input parameter "'.htmlspecialchars($_COOKIE['lang']).'" is not valid');
-    }
-  
-    $user['language'] = $_COOKIE['lang'];
+
+    $user['language'] = pwg_get_cookie_var('lang');
 
     if ($update_user)
     {
       single_update(
         USER_INFOS_TABLE,
         array(
-          'language' => $_COOKIE['lang']
+          'language' => pwg_get_cookie_var('lang')
         ),
         array(
           'user_id' => $user_id ?? $user['id']
@@ -1974,7 +1970,7 @@ function load_cookie_language($load_language=true, $update_user=false, $unset_co
       // We unset the lang cookie, if user has changed their language using interface
       // we don't want to keep setting it back to what was chosen using standard
       // pages lang switch
-      setcookie("lang", "", time() - 3600);
+      setcookie("pwg_lang", "", time() - 3600);
     }
   }
 }

password.php

@@ -499,7 +499,8 @@ foreach (get_languages() as $language_code => $language_name)
 
 $template->assign(array(
   'language_options' => $language_options,
-  'current_language' => $user['language']
+  'current_language' => $user['language'],
+  'COOKIE_PATH' => cookie_path(),
 ));
 
 //Get link to doc

register.php

@@ -112,6 +112,7 @@ foreach (get_languages() as $language_code => $language_name)
 $template->assign(array(
   'language_options' => $language_options,
   'current_language' => $user['language'],
+  'COOKIE_PATH' => cookie_path(),
 ));
 
 //Get link to doc

themes/standard_pages/js/standard_pages.js

@@ -88,8 +88,8 @@ function setCookie(cname, cvalue, exdays) {
   const d = new Date();
   d.setTime(d.getTime() + (exdays*24*60*60*1000));
   let expires = "expires="+ d.toUTCString();
-  document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
-  if (cname == "lang")
+  document.cookie = cname + "=" + cvalue + ";" + expires + ";path="+cookie_path;
+  if (cname == "pwg_lang")
   {
     location.reload();
   }
@@ -125,9 +125,9 @@ jQuery(".togglePassword").click(function(e){
 
 jQuery("#other-languages a").click(function(e){
   let clickedUrl = new URL(jQuery(e.target).attr('href'));
-  let selectedLang = clickedUrl.searchParams.get("lang");
+  let selectedLang = clickedUrl.searchParams.get("pwg_lang");
 
   if (selectedLang) {
-    setCookie('lang',selectedLang,1);
+    setCookie('pwg_lang',selectedLang,1);
   }
 });

themes/standard_pages/template/identification.tpl

@@ -5,6 +5,8 @@
   var selected_language = `{$language_options[$current_language]}`;
   var url_logo_light = `{$ROOT_URL}themes/standard_pages/images/piwigo_logo.svg`;
   var url_logo_dark = `{$ROOT_URL}themes/standard_pages/images/piwigo_logo_dark.svg`;
+  var cookie_path = {$COOKIE_PATH};
+
 </script>
 {combine_script id='standard_pages_js' load='async' require='jquery' path='themes/standard_pages/js/standard_pages.js'}
 
@@ -109,7 +111,7 @@
     <div id="lang-select">
       <span id="other-languages">
   {foreach from=$language_options key=code item=lang}
-          <span id="lang={$code}" onclick="setCookie('lang','{$code}',30)">{$lang}</span>
+          <span id="lang={$code}" onclick="setCookie('pwg_lang','{$code}',30)">{$lang}</span>
   {/foreach}
       </span>
       <div id="selected-language-container">

themes/standard_pages/template/password.tpl

@@ -166,7 +166,7 @@
     <div id="lang-select">
       <span id="other-languages">
   {foreach from=$language_options key=code item=lang}
-          <span id="lang={$code}" onclick="setCookie('lang','{$code}',30)">{$lang}</span>
+          <span id="pwg_lang={$code}" onclick="setCookie('pwg_lang','{$code}',30)">{$lang}</span>
   {/foreach}
       </span>
       <div id="selected-language-container">

themes/standard_pages/template/profile.tpl

@@ -481,7 +481,7 @@ const str_must_not_empty = "{'must not be empty'|translate|escape:javascript}";
       <div id="lang-select">
         <span id="other-languages">
           {foreach from=$language_options key=code item=lang}
-            <span id="lang={$code}" onclick="setCookie('lang','{$code}',30)">{$lang}</span>
+            <span id="pwg_lang={$code}" onclick="setCookie('pwg_lang','{$code}',30)">{$lang}</span>
           {/foreach}
         </span>
         <div id="selected-language-container">

themes/standard_pages/template/register.tpl

@@ -111,7 +111,7 @@
     <div id="lang-select">
       <span id="other-languages">
   {foreach from=$language_options key=code item=lang}
-          <span id="lang={$code}" onclick="setCookie('lang','{$code}',30)">{$lang}</span>
+          <span id="pwg_lang={$code}" onclick="setCookie('pwg_lang','{$code}',30)">{$lang}</span>
   {/foreach}
       </span>
       <div id="selected-language-container">