From 659f748dc94e3ec0593a4c5454be69dbc242d1c9 Mon Sep 17 00:00:00 2001
From: Rostislav Wolny <rosta@mailpoet.com>
Date: Tue, 31 Jul 2018 10:44:06 +0200
Subject: [PATCH] Add cache headers to cron endpoints

[MAILPOET-1464]
---
 lib/Cron/Daemon.php | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/Cron/Daemon.php b/lib/Cron/Daemon.php
index 7eb5d2d560..5f79b539d7 100644
--- a/lib/Cron/Daemon.php
+++ b/lib/Cron/Daemon.php
@@ -25,6 +25,7 @@ class Daemon {
   }
 
   function ping() {
+    $this->addCacheHeaders();
     $this->terminateRequest(self::PING_SUCCESS_RESPONSE);
   }
 
@@ -33,6 +34,7 @@ class Daemon {
     if(strpos(@ini_get('disable_functions'), 'set_time_limit') === false) {
       set_time_limit(0);
     }
+    $this->addCacheHeaders();
     if(!$this->request_data) {
       $error = __('Invalid or missing request data.', 'mailpoet');
     } else {
@@ -135,4 +137,16 @@ class Daemon {
       $daemon['token'] !== $this->token ||
       (isset($daemon['status']) && $daemon['status'] !== CronHelper::DAEMON_STATUS_ACTIVE);
   }
+
+  private function addCacheHeaders() {
+    if(headers_sent()) {
+      return;
+    }
+    // Common Cache Control header. Should be respected by cache proxies and CDNs.
+    header('Cache-Control: no-cache');
+    // Mark as blacklisted for SG Optimizer for sites hosted on SiteGround.
+    header('X-Cache-Enabled: False');
+    // Set caching header for LiteSpeed server.
+    header('X-LiteSpeed-Cache-Control: no-cache');
+  }
 }