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I have a CentOS box running Apache 2.2.3 and compression is working fine on HTTP connections, with the relevant information being logged to a separate deflate log. However, no information is being logged for HTTPS connections. I believe this is because the compression is being negotiated at the SSL layer but I'm not completely certain.

Compression over HTTPS has been tested and verified using information from this site, so I know it's working. Of course that test doesn't really tell me anything useful about how well compression is working or for which browsers. As the site in question has no static content it's not easily tested without using a browser, so just faking user agent strings won't help much.

Is there a way I can get information about compression logged for HTTPS connections?

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up vote 2 down vote accepted

Yeah, it's almost certainly due to the compression negotiated by mod_ssl.

You should be able to get the info on whether compression is actually happening for a given client with the SSL_COMPRESS_METHOD environment variable; but the nice statistical logging seems to be out of reach when letting SSL do the compression.

If you're really needing those nice statistics, one option would be to recompile openssl without zlib (there's got to be a better way to do this...), and get mod_deflate doing the compression instead.

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