Added squid cache control to AjaxCachePolicy, similar to what OutputPage does.

Experimental.

diff --git a/includes/AjaxFunctions.php b/includes/AjaxFunctions.php
index a1a4009..9804a24 100644 (file)
--- a/includes/AjaxFunctions.php
+++ b/includes/AjaxFunctions.php
@@ -88,16 +88,41 @@ class AjaxCachePolicy {
        }
 
        function writeHeader() {
+               global $wgUseSquid, $wgUseESI, $wgSquidMaxage;
+               
                header ("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
-               if ( is_null( $this->policy ) ) {
-                       // Bust cache in the head
+               
+               if ( $this->policy ) {
+                       
+                       # If squid caches are configured, tell them to cache the response, 
+                       # and tell the client to always check with the squid. Otherwise,
+                       # tell the client to use a cached copy, without a way to purge it.
+                       
+                       if( $wgUseSquid ) {
+                               
+                               # Expect explicite purge of the proxy cache, but require end user agents
+                               # to revalidate against the proxy on each visit.
+                               # Surrogate-Control controls our Squid, Cache-Control downstream caches
+                               
+                               if ( $wgUseESI ) {
+                                       header( 'Surrogate-Control: max-age='.$this->policy.', content="ESI/1.0"');
+                                       header( 'Cache-Control: s-maxage=0, must-revalidate, max-age=0' );
+                               } else {
+                                       header( 'Cache-Control: s-maxage='.$this->policy.', must-revalidate, max-age=0' );
+                               }
+                               
+                       } else {
+                       
+                               # Let the client do the caching. Cache is not purged.
+                               header ("Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->policy ) . " GMT");
+                               header ("Cache-Control: s-max-age={$this->policy},public,max-age={$this->policy}");
+                       }
+                       
+               } else {
+                       # always expired, always modified
                        header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT");    // Date in the past
-                       // always modified
                        header ("Cache-Control: no-cache, must-revalidate");  // HTTP/1.1
                        header ("Pragma: no-cache");                          // HTTP/1.0
-               } else {
-                       header ("Expires: " . gmdate( "D, d M Y H:i:s", time() + $this->policy ) . " GMT");
-                       header ("Cache-Control: s-max-age={$this->policy},public,max-age={$this->policy}");
                }
                
                if ( $this->vary ) {