From fba0f09f4f3f3d605b312464d5f1d046d0c1db8e Mon Sep 17 00:00:00 2001
From: Matthieu Gautier <mgautier@kymeria.fr>
Date: Tue, 26 Apr 2022 14:25:53 +0200
Subject: [PATCH] Do not compress content smaller than 1400 Bytes

---
 src/server/response.cpp | 11 +++++++++--
 test/server.cpp         |  8 ++++----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/server/response.cpp b/src/server/response.cpp
index c149d59c7..ae80a5846 100644
--- a/src/server/response.cpp
+++ b/src/server/response.cpp
@@ -33,8 +33,15 @@
 
 #include <array>
 
-
-#define KIWIX_MIN_CONTENT_SIZE_TO_COMPRESS 100
+// This is somehow a magic value.
+// If this value is too small, we will compress (and lost cpu time) too much
+// content.
+// If this value is too big, we will not compress enough content and send too
+// much data.
+// If we assume that MTU is 1500 Bytes it is useless to compress
+// content smaller as the content will be sent in one packet anyway.
+// 1400 Bytes seems to be a common accepted limit.
+#define KIWIX_MIN_CONTENT_SIZE_TO_COMPRESS 1400
 
 namespace kiwix {
 
diff --git a/test/server.cpp b/test/server.cpp
index bf02a70cd..9f4356b5a 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -185,13 +185,10 @@ const ResourceCollection resources200Compressible{
   { WITH_ETAG, "/ROOT/skin/taskbar.css" },
   { WITH_ETAG, "/ROOT/skin/block_external.js" },
 
-  { NO_ETAG,   "/ROOT/catalog/root.xml" },
-  { NO_ETAG,   "/ROOT/catalog/searchdescription.xml" },
   { NO_ETAG,   "/ROOT/catalog/search" },
 
   { NO_ETAG,   "/ROOT/search?content=zimfile&pattern=a" },
 
-  { NO_ETAG,   "/ROOT/suggest?content=zimfile" },
   { NO_ETAG,   "/ROOT/suggest?content=zimfile&term=ray" },
 
   { NO_ETAG,   "/ROOT/catch/external?source=www.example.com" },
@@ -224,7 +221,10 @@ const ResourceCollection resources200Uncompressible{
   { WITH_ETAG, "/ROOT/corner_cases/-/empty.css" },
   { WITH_ETAG, "/ROOT/corner_cases/-/empty.js" },
 
-  // The title and creator are too small to be compressed
+  // The following url's responses are too small to be compressed
+  { NO_ETAG,   "/ROOT/catalog/root.xml" },
+  { NO_ETAG,   "/ROOT/catalog/searchdescription.xml" },
+  { NO_ETAG,   "/ROOT/suggest?content=zimfile" },
   { WITH_ETAG, "/ROOT/raw/zimfile/meta/Creator" },
   { WITH_ETAG, "/ROOT/raw/zimfile/meta/Title" },
 };