Browser tries to download download.gz instead of showing the page

Hello @hydrogriff,
I am sorry about the issue you are experiencing with download.gz but I am happy to assist you with this.
W3TC_PAGECACHE_STORE_COMPRESSION_OFF constant allows not to generate
_gzip and similar files. It helps in the cases when server configuration
doesn’t allow mime type overwrites so cached content ends up with browser
download action.
It’s located in /wp-content/plugins/w3-total-cache/PgCache_ContentGrabber.php line 1191

if ( defined( 'W3TC_PAGECACHE_STORE_COMPRESSION_OFF' ) ) {
			return $compressions;
		}

You just need to add define('W3TC_PAGECACHE_STORE_COMPRESSION_OFF', true);

to the wp-config.php file.

I hope this helps

Thank you for the detailed response Marko. I would like to know what is the issue here. Should I add the fix in the wp-config (which I assume will stop W3TC from storing .gzip files)? Or should I configure my server to allow MIME type overrides?

If it’s the latter, could you show me a hint on how to do that?

Loaded Modules:
 core_module (static)
 so_module (static)
 watchdog_module (static)
 http_module (static)
 log_config_module (static)
 logio_module (static)
 version_module (static)
 unixd_module (static)
 access_compat_module (shared)
 alias_module (shared)
 auth_basic_module (shared)
 authn_core_module (shared)
 authn_file_module (shared)
 authz_core_module (shared)
 authz_host_module (shared)
 authz_user_module (shared)
 autoindex_module (shared)
 deflate_module (shared)
 dir_module (shared)
 env_module (shared)
 expires_module (shared)
 filter_module (shared)
 headers_module (shared)
 mime_module (shared)
 mpm_prefork_module (shared)
 negotiation_module (shared)
 php7_module (shared)
 reqtimeout_module (shared)
 rewrite_module (shared)
 setenvif_module (shared)
 socache_shmcb_module (shared)
 ssl_module (shared)
 status_module (shared)

These are the active modules from one of the servers.

• This reply was modified 5 years, 4 months ago by hydrogriff.
• This reply was modified 5 years, 4 months ago by hydrogriff.

Hi. Kindly check my previous reply. As I edited it to add a code snippet, the spam filter caught it into moderation. I have added some info.

Hello @hydrogriff,

The fix I provided will solve your download.gz issue. As for the server, you should contact your host/server admin for assistance.

Thanks.

As I mentioned in the previous response, I would like to know what the issue is. Does the fix disable gzip compression totally? What does the fix do?

And about the server, I am the one who maintains it. I see that mime_module is installed. Just not sure where should I start looking for the config. I am a junior developer and I have little experience with core server configs. If it’s not too much to ask, can you point me to the documentation that deals with MIME handling configs – so that I can reproduce the issue in a test server and check if I can find what’s causing the issue.

Hello @hydrogriff,

The problem with downloading gzip files is probably that there already is a configuration in the setup that handles gzip files. If you enable gzip in Performance => Browser Cache => HTML & XML, the configuration gets messed up and the browser will download a gzip file in situations like yours. Disabling the gzip option in Performance => Browser Cache => HTML & XML will probably solve this issue.

Thank you for the clarification.