MEDIUM: HTTP compression (zlib library support)
This commit introduces HTTP compression using the zlib library.
http_response_forward_body has been modified to call the compression
functions.
This feature includes 3 algorithms: identity, gzip and deflate:
* identity: this is mostly for debugging, and it was useful for
developping the compression feature. With Content-Length in input, it
is making each chunk with the data available in the current buffer.
With chunks in input, it is rechunking, the output chunks will be
bigger or smaller depending of the size of the input chunk and the
size of the buffer. Identity does not apply any change on data.
* gzip: same as identity, but applying a gzip compression. The data
are deflated using the Z_NO_FLUSH flag in zlib. When there is no more
data in the input buffer, it flushes the data in the output buffer
(Z_SYNC_FLUSH). At the end of data, when it receives the last chunk in
input, or when there is no more data to read, it writes the end of
data with Z_FINISH and the ending chunk.
* deflate: same as gzip, but with deflate algorithm and zlib format.
Note that this algorithm has ambiguous support on many browsers and
no support at all from recent ones. It is strongly recommended not
to use it for anything else than experimentation.
You can't choose the compression ratio at the moment, it will be set to
Z_BEST_SPEED (1), as tests have shown very little benefit in terms of
compression ration when going above for HTML contents, at the cost of
a massive CPU impact.
Compression will be activated depending of the Accept-Encoding request
header. With identity, it does not take care of that header.
To build HAProxy with zlib support, use USE_ZLIB=1 in the make
parameters.
This work was initially started by David Du Colombier at Exceliance.
diff --git a/README b/README
index b886eee..d403711 100644
--- a/README
+++ b/README
@@ -89,6 +89,10 @@
if the build fails due to missing symbols such as deflateInit(), then try again
with "ADDLIB=-lz".
+It is also possible to include native support for ZLIB to benefit from HTTP
+compression. For this, pass "USE_ZLIB=1" on the "make" command line and ensure
+that zlib is present on the system.
+
By default, the DEBUG variable is set to '-g' to enable debug symbols. It is
not wise to disable it on uncommon systems, because it's often the only way to
get a complete core when you need one. Otherwise, you can set DEBUG to '-s' to
@@ -102,11 +106,12 @@
$ make -f Makefile.bsd REGEX=pcre DEBUG= COPTS.generic="-Os -fomit-frame-pointer -mgnu"
-And on a recent Linux with SSL support :
+And on a recent Linux with SSL and ZLIB support :
- $ make TARGET=linux2628 CPU=native USE_PCRE=1 USE_OPENSSL=1
+ $ make TARGET=linux2628 CPU=native USE_PCRE=1 USE_OPENSSL=1 USE_ZLIB=1
-In order to build a 32-bit binary on an x86_64 Linux system with SSL support :
+In order to build a 32-bit binary on an x86_64 Linux system with SSL support
+without support for compression but when OpenSSL requires ZLIB anyway :
$ make TARGET=linux26 ARCH=i386 USE_OPENSSL=1 ADDLIB=-lz