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apache.htaccessgzipcpanelwhm

Compression (gzip) is not working when an htaccess redirect is applied

I have an Linux web server running WHM/cPanel.

This has a page uploaded in the /public_html folder called compression.php This is accessed with http://www.example.com/compression.php

Within cPanel, in 'Optimize Website', the 'Compress All Content' option is selected and the .htaccess file does have a mod_gzip block - see below:

<ifModule mod_gzip.c>
    mod_gzip_on Yes
    mod_gzip_dechunk Yes
    mod_gzip_item_include file .(html?|txt|css|js|php|pl)$
    mod_gzip_item_include handler ^cgi-script$
    mod_gzip_item_include mime ^text/.*
    mod_gzip_item_include mime ^application/x-javascript.*
    mod_gzip_item_exclude mime ^image/.*
    mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*
</ifModule>

Using https://www.whatsmyip.org/http-compression-test/ to test, I can see that the page IS being compressed as expected.

There is a /public_html/public folder which also has a file called compression.php (with slightly different content to differentiate it). When I access this using http://www.example.com/public/compression.php, the page is also compressed.

But, if I want to redirect ALL traffic to the /public_html/public folder in the .htaccess file, I add the following:

<IfModule mod_rewrite.c>
    Options +FollowSymlinks
    RewriteEngine On

    # Rewrite to 'public' folder
    RewriteCond %{HTTP_HOST} ^dev43.360ss.com$
    RewriteCond %{REQUEST_URI} !public/
    RewriteRule (.*) public/$1 [L]
</IfModule>

The page in /public loads on the http://www.example.com/compression.php URL & shows the correct content, but it's not compressed any more.

As suggested by cPanel support, I've tried having the mod_gzip block ABOVE the mod_rewrite block in the htaccess.

Because it's compressed without the htaccess redirect, we know gzip is installed & working. And I've tested that the same happens no matter what version of PHP is used (I've tested 7.1, 7.2 & 7.3). I've also tested with php files and an image file - no difference.

Does anyone have any ideas?

Thanks

Solution

  • Turns out, this was the 'Backend Compression' setting in the ModSecurity™ Configuration set to Disabled instead of Enabled!