Index: CacheFilter.java
===================================================================
RCS file: /cvs/oscache/src/core/java/com/opensymphony/oscache/web/filter/CacheFilter.java,v
retrieving revision 1.5
diff -u -r1.5 CacheFilter.java
--- CacheFilter.java	22 Feb 2005 17:17:02 -0000	1.5
+++ CacheFilter.java	21 Mar 2005 10:47:04 -0000
@@ -35,6 +35,7 @@
     // Header
     public static final String HEADER_LAST_MODIFIED = "Last-Modified";
     public static final String HEADER_CONTENT_TYPE = "Content-Type";
+    public static final String HEADER_CONTENT_ENCODING = "Content-Encoding";
     public static final String HEADER_EXPIRES = "Expires";
     public static final String HEADER_IF_MODIFIED_SINCE = "If-Modified-Since";
     
@@ -120,7 +121,11 @@
                 }
             }
 
-            respContent.writeTo(response, fragmentRequest);
+            boolean supportGZIP = false;
+            if (respContent.isContentGziped()) {
+                supportGZIP = isGZIPSupported((HttpServletRequest)request);
+            }
+            respContent.writeTo(response, fragmentRequest, supportGZIP);
             
         } catch (NeedsRefreshException nre) {
             boolean updateSucceeded = false;
@@ -246,5 +251,19 @@
     public boolean isFilteredBefore(ServletRequest request) {
         return request.getAttribute(REQUEST_FILTERED) != null;
     }
-    
+
+    /**
+     * @param request
+     * @return true if client supports GZIP
+    */
+    protected boolean isGZIPSupported(HttpServletRequest request) {
+        String acceptEncoding = request.getHeader("Accept-Encoding");
+
+        if ((acceptEncoding != null) && (acceptEncoding.indexOf("gzip") != -1)) {
+            return true;
+        }
+
+        return false;
+    }
+
 }
Index: CacheHttpServletResponseWrapper.java
===================================================================
RCS file: /cvs/oscache/src/core/java/com/opensymphony/oscache/web/filter/CacheHttpServletResponseWrapper.java,v
retrieving revision 1.6
diff -u -r1.6 CacheHttpServletResponseWrapper.java
--- CacheHttpServletResponseWrapper.java	23 Feb 2005 17:55:29 -0000	1.6
+++ CacheHttpServletResponseWrapper.java	21 Mar 2005 10:47:04 -0000
@@ -143,7 +143,10 @@
         if (CacheFilter.HEADER_CONTENT_TYPE.equalsIgnoreCase(name)) {
             result.setContentType(value);
         }        
-        
+        if (CacheFilter.HEADER_CONTENT_ENCODING.equalsIgnoreCase(name)) {
+            result.setContentEncoding(value);
+        }
+
         super.setHeader(name, value);
     }
 
@@ -161,6 +164,9 @@
         if (CacheFilter.HEADER_CONTENT_TYPE.equalsIgnoreCase(name)) {
             result.setContentType(value);
         }        
+        if (CacheFilter.HEADER_CONTENT_ENCODING.equalsIgnoreCase(name)) {
+            result.setContentEncoding(value);
+        }
         
         super.addHeader(name, value);
     }
Index: ResponseContent.java
===================================================================
RCS file: /cvs/oscache/src/core/java/com/opensymphony/oscache/web/filter/ResponseContent.java,v
retrieving revision 1.3
diff -u -r1.3 ResponseContent.java
--- ResponseContent.java	22 Feb 2005 17:17:02 -0000	1.3
+++ ResponseContent.java	21 Mar 2005 10:47:04 -0000
@@ -7,9 +7,12 @@
 import java.io.*;
 
 import java.util.Locale;
+import java.util.zip.GZIPInputStream;
 
 import javax.servlet.ServletResponse;
+import javax.servlet.ServletRequest;
 import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpServletRequest;
 
 /**
  * Holds the servlet response in a byte array so that it can be held
@@ -23,6 +26,7 @@
     private transient ByteArrayOutputStream bout = new ByteArrayOutputStream(1000);
     private Locale locale = null;
     private String contentType = null;
+    private String contentEncoding = null;
     private byte[] content = null;
     private long lastModified = -1;
     private long expires = Long.MAX_VALUE;
@@ -35,6 +39,14 @@
         contentType = value;
     }
 
+    /**
+     * Set the content encoding. We capture this so that when we serve this
+     * data from cache, we can set the correct content encoding on the response.
+     */
+    public void setContentEncoding(String contentEncoding) {
+        this.contentEncoding = contentEncoding;
+    }
+
     public long getLastModified() {
         return lastModified;
     }
@@ -97,10 +109,11 @@
      * Writes this cached data out to the supplied <code>ServletResponse</code>.
      *
      * @param response The servlet response to output the cached content to.
+     * @param supportGZIP trus if the client browser supports GZIP
      * @throws IOException
      */
-    public void writeTo(ServletResponse response) throws IOException {
-        writeTo(response, false);
+    public void writeTo(ServletResponse response, boolean supportGZIP) throws IOException {
+        writeTo(response, false, supportGZIP);
     }
     
     /**
@@ -108,9 +121,10 @@
      *
      * @param response The servlet response to output the cached content to.
      * @param fragment is true if this content a fragment or part of a page
+     * @param supportGZIP trus if the client browser supports GZIP
      * @throws IOException
      */
-    public void writeTo(ServletResponse response, boolean fragment) throws IOException {
+    public void writeTo(ServletResponse response, boolean fragment, boolean supportGZIP) throws IOException {
         //Send the content type and data to this response
         if (contentType != null) {
             response.setContentType(contentType);
@@ -128,7 +142,39 @@
         }
 
         OutputStream out = new BufferedOutputStream(response.getOutputStream());
+
+        if (isContentGziped()) {
+            if (supportGZIP) {
+                ((HttpServletResponse) response).addHeader("Content-Encoding", "gzip");
+            } else {
+                // client doesn't support, so we have to uncompress it
+                ByteArrayInputStream bais = new ByteArrayInputStream(content);
+                GZIPInputStream zis = new GZIPInputStream(bais);
+
+                ByteArrayOutputStream baos = new ByteArrayOutputStream();
+                int numBytesRead = 0;
+                byte[] tempBytes = new byte[512];
+
+                while ((numBytesRead = zis.read(tempBytes, 0, tempBytes.length)) != -1) {
+                    baos.write(tempBytes, 0, numBytesRead);
+                }
+
+                byte[] result = baos.toByteArray();
+                response.setContentLength(result.length);
+                out.write(result);
+                out.flush();
+                return;
+            }
+        }
+
         out.write(content);
         out.flush();
+    }
+
+    /**
+     * @return true if the content is GZIP compressed
+     */
+    public boolean isContentGziped() {
+        return "gzip".equals(contentEncoding);
     }
 }