I have two files named test.html and test.php on my server, having the same content:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
<title>TEMPLATE</title>
</head>
<body>
TEXT
</body>
</html>
Besides that I have a .htaccess-files with the following content:
RewriteEngine On
RewriteBase /
RewriteRule ^(.*)\.(php3|php4|php5|php6|html|htm) $1\.php
AddType x-mapp-php5.5 .php
AddHandler x-mapp-php5.5 .php
<IfModule mod_deflate.c>
AddOutputFilterByType DEFLATE text/html
</Ifmodule>
Requesting test.html returns the following headers:
Connection: Keep-Alive
Content-Type: text/html
Date: Fri, 01 Jul 2016 08:32:04 GMT
Keep-Alive: timeout=2, max=200
Server: Apache
Transfer-Encoding: chunked
x-powered-by: PHP/5.5.36
After uncommenting the rewrite part (thus using HTML without beeing processed by PHP), the response headers are:
Accept-Ranges: bytes
Connection: Keep-Alive
Content-Encoding: gzip
Content-Length: 186
Content-Type: text/html
Date: Fri, 01 Jul 2016 08:42:22 GMT
Etag: "xxxxxxxx-xx-xxxxxxxxxxxxx"
Keep-Alive: timeout=2, max=200
Last-Modified: Fri, 01 Jul 2016 08:42:03 GMT
Server: Apache
Vary: Accept-Encoding
It's exactly the same content and exactly the same header, but why is the content not compressed, when it is returned by PHP?
Add the following line in your .htaccess
php_value zlib.output_compression 1
to enable PHP output compression.
More information at http://php.net/manual/en/zlib.configuration.php#ini.zlib.output-compression