How output data with gzip header and not deflate header - php

Question

I'm testing compression of html files.
I have 2 HTML files:
Not compressed HTML file ( content will change )
Compressed HTML file .gz ( content won't change )
Using PHP I'm trying to output compressed files data and here begins.
test with already compressed html file.
//header gzip
$data = getfile($name); // custom function packed with fopen fread
header(Content-Encoding: gzip); // header works perfect
echo $data; // output OK
//header deflate
$data = getfile($name); // custom function packed with fopen fread
header(Content-Encoding: deflate); // file was gzip compressed so error is normal
echo $data; // fireFox : Content Encoding Error
test with not compressed html file
//header gzip using gzcompress();
$data = gzcompress(getfile($name), 9);
header(Content-Encoding: gzip); // somehow header is bad
echo $data; // fireFox : Content Encoding Error , but IE 9 output OK
but here we got magic
//header deflate using gzcompress();
$data = gzcompress(getfile($name), 9);
header(Content-Encoding: deflate); // header works perfect
echo $data; // Firefox output OK, but IE output ERROR
How fix this crazy thing and send all data as gzip with gzip header not defalte? maybe someone have any idea what is wrong?
Thank you

Answer 1

The HTTP spec. (RFC2616) says:
gzip
An encoding format produced by the file compression program
"gzip" (GNU zip) as described in RFC 1952 [25].
compress
The encoding format produced by the common UNIX file compression
program "compress".
deflate
The "zlib" format defined in RFC 1950 [31] in combination with
the "deflate" compression mechanism described in RFC 1951 [29].
The PHP docs say:
gzcompress
For details on the ZLIB compression algorithm see the document
"ZLIB Compressed Data Format Specification version 3.3"
(RFC 1950).
gzdeflate
For details on the DEFLATE compression algorithm see the document
"DEFLATE Compressed Data Format Specification version 1.3"
(RFC 1951).
gzencode
For more information on the GZIP file format, see the document:
GZIP file format specification version 4.3 (RFC 1952).
From this, one can come to the conclusion that gzencode() must be used with gzip, and gzcompress() (with the DEFLATE encoding) must be used with deflate.
The first combination works for me. I haven't tried the second; don't know why it wouldn't work with IE. A URL might help to trouble-shoot that problem.