From e6918cd1bde0f547415d0e041ef793c54b5dc4b1 Mon Sep 17 00:00:00 2001
From: Isaac Connor <isaac@zoneminder.com>
Date: Wed, 1 Nov 2017 09:41:19 -0400
Subject: [PATCH] implement crude cache busting code for .js and .css files

---
 web/includes/functions.php               | 14 +++++++++++++-
 web/skins/classic/includes/functions.php | 10 +++++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/web/includes/functions.php b/web/includes/functions.php
index 012dc7760..c84eab8ed 100644
--- a/web/includes/functions.php
+++ b/web/includes/functions.php
@@ -2060,6 +2060,18 @@ function detaintPath( $path ) {
   return( $path );
 }
 
+function cache_bust( $file ) {
+  # Use the last modified timestamp to create a link that gets a different filename
+  # To defeat caching.  Should probably use md5 hash
+  $cacheFile = '/cache/'.basename($file).'-'.filemtime($file);
+  if ( file_exists( ZM_PATH_WEB.$cacheFile ) or symlink( ZM_PATH_WEB.'/'.$file, ZM_PATH_WEB.$cacheFile ) ) {
+    return $cacheFile;
+  } else {
+    Warning("Failed linking $file to $cacheFile");
+  }
+  return $file;
+}
+
 function getSkinFile( $file ) {
   global $skinBase;
   $skinFile = false;
@@ -2068,7 +2080,7 @@ function getSkinFile( $file ) {
     if ( file_exists( $tempSkinFile ) )
       $skinFile = $tempSkinFile;
   }
-  return( $skinFile );
+  return  $skinFile;
 }
 
 function getSkinIncludes( $file, $includeBase=false, $asOverride=false ) {
diff --git a/web/skins/classic/includes/functions.php b/web/skins/classic/includes/functions.php
index 26cb1a26e..c2b5a14de 100644
--- a/web/skins/classic/includes/functions.php
+++ b/web/skins/classic/includes/functions.php
@@ -60,11 +60,11 @@ if ( file_exists( "skins/$skin/css/$css/graphics/favicon.ico" ) ) {
   <link rel="stylesheet" href="css/reset.css" type="text/css"/>
   <link rel="stylesheet" href="css/overlay.css" type="text/css"/>
   <link rel="stylesheet" href="css/bootstrap.min.css" type="text/css"/>
-  <link rel="stylesheet" href="<?php echo $skinCssFile ?>" type="text/css" media="screen"/>
+  <link rel="stylesheet" href="<?php echo cache_bust($skinCssFile) ?>" type="text/css" media="screen"/>
 <?php
   if ( $viewCssFile ) {
 ?>
-  <link rel="stylesheet" href="<?php echo $viewCssFile ?>" type="text/css" media="screen"/>
+  <link rel="stylesheet" href="<?php echo cache_bust($viewCssFile) ?>" type="text/css" media="screen"/>
 <?php
   }
   if ( $viewCssPhpFile ) {
@@ -138,18 +138,18 @@ if ( file_exists( "skins/$skin/css/$css/graphics/favicon.ico" ) ) {
   }
 	if ( $cssJsFile ) {
 ?>
-  <script type="text/javascript" src="<?php echo $cssJsFile ?>"></script>
+  <script type="text/javascript" src="<?php echo cache_bust($cssJsFile) ?>"></script>
 <?php
 } else {
 ?>
   <script type="text/javascript" src="skins/classic/js/classic.js"></script>
 <?php } ?>
-  <script type="text/javascript" src="<?php echo $skinJsFile ?>"></script>
+  <script type="text/javascript" src="<?php echo cache_bust($skinJsFile) ?>"></script>
   <script type="text/javascript" src="js/logger.js"></script>
 <?php
   if ( $viewJsFile ) {
 ?>
-  <script type="text/javascript" src="<?php echo $viewJsFile ?>"></script>
+  <script type="text/javascript" src="<?php echo cache_bust($viewJsFile) ?>"></script>
 <?php
   }
 ?>