From 75aea05a8a3d24beff1eb7fe1e243c8bc2e2eb96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Thu, 4 Oct 2018 09:30:51 +0200
Subject: [PATCH] Add jax rs response filter for gzip compression

---
 .../sonia/scm/filter/GZipResponseFilter.java  | 23 +++++++++++++++++++
 .../src/main/java/sonia/scm/util/WebUtil.java |  8 ++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 scm-core/src/main/java/sonia/scm/filter/GZipResponseFilter.java

diff --git a/scm-core/src/main/java/sonia/scm/filter/GZipResponseFilter.java b/scm-core/src/main/java/sonia/scm/filter/GZipResponseFilter.java
new file mode 100644
index 0000000000..8a84446151
--- /dev/null
+++ b/scm-core/src/main/java/sonia/scm/filter/GZipResponseFilter.java
@@ -0,0 +1,23 @@
+package sonia.scm.filter;
+
+import lombok.extern.slf4j.Slf4j;
+import sonia.scm.util.WebUtil;
+
+import javax.ws.rs.container.ContainerRequestContext;
+import javax.ws.rs.container.ContainerResponseContext;
+import javax.ws.rs.container.ContainerResponseFilter;
+import javax.ws.rs.ext.Provider;
+import java.io.IOException;
+import java.util.zip.GZIPOutputStream;
+
+@Provider
+@Slf4j
+public class GZipResponseFilter implements ContainerResponseFilter {
+  public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext) throws IOException {
+    if (WebUtil.isGzipSupported(requestContext::getHeaderString)) {
+      log.trace("compress output with gzip");
+      GZIPOutputStream wrappedResponse = new GZIPOutputStream(responseContext.getEntityStream());
+      responseContext.setEntityStream(wrappedResponse);
+    }
+  }
+}
diff --git a/scm-core/src/main/java/sonia/scm/util/WebUtil.java b/scm-core/src/main/java/sonia/scm/util/WebUtil.java
index 2fc0876668..a9337b0598 100644
--- a/scm-core/src/main/java/sonia/scm/util/WebUtil.java
+++ b/scm-core/src/main/java/sonia/scm/util/WebUtil.java
@@ -49,6 +49,7 @@ import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Locale;
 import java.util.TimeZone;
+import java.util.function.Function;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -266,7 +267,12 @@ public final class WebUtil
    */
   public static boolean isGzipSupported(HttpServletRequest request)
   {
-    String enc = request.getHeader(HEADER_ACCEPTENCODING);
+    return isGzipSupported(request::getHeader);
+  }
+
+  public static boolean isGzipSupported(Function<String, String> headerResolver)
+  {
+    String enc = headerResolver.apply(HEADER_ACCEPTENCODING);
 
     return (enc != null) && enc.contains("gzip");
   }