Add capability to send pre-compressed js & css files if the browser can accept them

- save a gzipped version of js & css files at the same time as the uncompressed version is cache
- basic content negotiation to send the compressed files
- uses sendfile (for compressed or uncompressed versions) if config indicates its available

darcs-hash:20090118184354-f07c6-66c5b465ab147d83de409708bab2c47d1dafcf8d.gz

inc/pageutils.php

@@ -578,6 +578,9 @@ function http_conditionalRequest($timestamp){
   exit;
 }
 
+/**
+ *   common routines for handling communication with the client (browser)
+ */
 function http_sendfile($file) {
   global $conf;
 
@@ -596,4 +599,23 @@ function http_sendfile($file) {
   return false;
 }
 
+function http_accepts_gzip() {
+  return !empty($_SERVER['HTTP_ACCEPT_ENCODING']) && (strpos($_SERVER['HTTP_ACCEPT_ENCODING'],'gzip') !== false);
+}
+
+function http_accepts_deflate() {
+  return !empty($_SERVER['HTTP_ACCEPT_ENCODING']) && (strpos($_SERVER['HTTP_ACCEPT_ENCODING'],'deflate') !== false);    
+}
+/**
+ * return true if there exists a gzip version of the uncompressed file (samepath/samefilename.sameext.gz)
+ * created after the uncompressed file
+ */
+function http_gzip_valid($uncompressed_file) {
+  $gzip = $uncompressed_file.'.gz';
+  if (filemtime($gzip) < filemtime($uncompressed_file)) {    // filemtime returns false (0) if file doesn't exist
+    return copy($uncompressed_file, 'compress.zlib://'.$gzip);
+  }
+
+  return true;
+}
 //Setup VIM: ex: et ts=2 enc=utf-8 :

lib/exe/css.php

@@ -92,7 +92,20 @@ function css_out(){
     if(css_cacheok($cache,array_keys($files),$tplinc)){
         http_conditionalRequest(filemtime($cache));
         if($conf['allowdebug']) header("X-CacheUsed: $cache");
-        readfile($cache);
+
+        // finally send output
+        if (http_accepts_gzip() && http_gzip_valid($cache)) {
+          header('Vary: Accept-Encoding');
+          header('Content-Encoding: gzip');
+          if (!http_sendfile($cache.'.gz')) readfile($cache.".gz");
+#        } else if (http_accepts_deflate()) {
+#          header('Vary: Accept-Encoding');
+#          header('Content-Encoding: deflate');
+#          readfile($cache.".zip");
+        } else {
+          if (!http_sendfile($cache)) readfile($cache);
+        }
+
         return;
     } else {
         http_conditionalRequest(time());
@@ -124,9 +137,20 @@ function css_out(){
 
     // save cache file
     io_saveFile($cache,$css);
+    copy($cache,"compress.zlib://$cache.gz");
 
     // finally send output
-    print $css;
+    if (http_accepts_gzip()) {
+      header('Vary: Accept-Encoding');
+      header('Content-Encoding: gzip');
+      print gzencode($css,9,FORCE_GZIP);
+#    } else if (http_accepts_deflate()) {
+#      header('Vary: Accept-Encoding');
+#      header('Content-Encoding: deflate');
+#      print gzencode($css,9,FORCE_DEFLATE);
+    } else {
+      print $css;
+    }
 }
 
 /**

lib/exe/js.php

@@ -64,7 +64,20 @@ function js_out(){
     if(js_cacheok($cache,array_merge($files,$plugins))){
         http_conditionalRequest(filemtime($cache));
         if($conf['allowdebug']) header("X-CacheUsed: $cache");
-        readfile($cache);
+
+        // finally send output
+        if (http_accepts_gzip() && http_gzip_valid($cache)) {
+          header('Vary: Accept-Encoding');
+          header('Content-Encoding: gzip');
+          if (!http_sendfile($cache.'.gz')) readfile($cache.".gz");
+#        } else if (http_accepts_deflate()) {
+#          header('Vary: Accept-Encoding');
+#          header('Content-Encoding: deflate');
+#          readfile($cache.".zip");
+        } else {
+          if (!http_sendfile($cache)) readfile($cache);
+        }
+
         return;
     } else {
         http_conditionalRequest(time());
@@ -147,9 +160,20 @@ function js_out(){
 
     // save cache file
     io_saveFile($cache,$js);
+    copy($cache,"compress.zlib://$cache.gz");
 
     // finally send output
-    print $js;
+    if (http_accepts_gzip()) {
+      header('Vary: Accept-Encoding');
+      header('Content-Encoding: gzip');
+      print gzencode($js,9,FORCE_GZIP);
+#    } else if (http_accepts_deflate()) {
+#      header('Vary: Accept-Encoding');
+#      header('Content-Encoding: deflate');
+#      print gzencode($js,9,FORCE_DEFLATE);
+    } else {
+      print $js;
+    }
 }
 
 /**