leaving the record of attempted gzip encoding problem fix.

core/src/main/java/hudson/security/HudsonAuthenticationEntryPoint.java

@@ -33,6 +33,8 @@ import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import static javax.servlet.http.HttpServletResponse.SC_FORBIDDEN;
+
+import java.io.FilterOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
@@ -81,12 +83,14 @@ public class HudsonAuthenticationEntryPoint extends AuthenticationProcessingFilt
             PrintWriter out;
             try {
                 OutputStream sout = rsp.getOutputStream();
-                if (rsp.containsHeader("Content-Encoding")) {
-                    // we serve Jelly pages with Content-Encoding:gzip.
-                    // ServletResponse doesn't provide means for us to check the value of the header,
-                    // so this is a hack.
-                    sout = new GZIPOutputStream(sout);
-                }
+//                if (rsp.containsHeader("Content-Encoding")) {
+//                    // we serve Jelly pages with Content-Encoding:gzip.
+//                    // ServletResponse doesn't provide means for us to check the value of the header,
+//                    // to make the matter worse, GZIPOutputStream writes a header right away,
+//                    // so by the time we get here we already have GZip header. Skip that part away by skipping first 10 bytes.
+//                    // this is a hack.
+//                    sout = new GZIPOutputStream(new ChopHeaderOutputStream(sout,10));
+//                }
                 out = new PrintWriter(new OutputStreamWriter(sout));
             } catch (IllegalStateException e) {
                 out = rsp.getWriter();
@@ -103,7 +107,35 @@ public class HudsonAuthenticationEntryPoint extends AuthenticationProcessingFilt
             // See http://support.microsoft.com/kb/294807
             for (int i=0; i < 10; i++)
                 out.print("                              ");
-            out.flush();
+            out.close();
+        }
+    }
+
+    private static class ChopHeaderOutputStream extends FilterOutputStream {
+        private int count;
+
+        ChopHeaderOutputStream(OutputStream out, int count) {
+            super(out);
+            this.count = count;
+        }
+        
+        @Override
+        public void write(byte[] b, int off, int len) throws IOException {
+            int i = Math.min(len,count);
+            count-=i;
+            off+=i;
+            len-=i;
+
+            if (len>0)
+                out.write(b, off, len);
+        }
+
+        @Override
+        public void write(int b) throws IOException {
+            if (count>0)
+                count--;
+            else
+                out.write(b);
         }
     }
 }