ZF-4632: Zend_Cache_Frontend_Page cannot handle contents with client dependend content-encodings
I deliver the page content in gzipped format, if the browser supports this. So every page can have to versions, a standard version and a gzipped one. The problem is, that you'll see the gzipped content instead of the webpage if the browser doesn't support this encoding (but the browser before supported it, so that the content has been cached gzipped).
At the moment it's not possible to tell Zend_Cache_Frontend_Page to differ between both versions, as the info if gzip encoding is supported is contained in the $_SERVER variable - and there's no option to use the $_SERVER variable for the cache key generation.
I don't know what would be best - an option to include the client encoding, the complete $_SERVER variable or a general option to set own variables, to influence the cache key. At the moment I use a workaround by setting an additional $_GET variable.
To test this, simply save an gzip encoded page in the cache and reload the page with a manipulated header (e.g. by changing "network.http.accept-encoding" in the Firfox configuration). Of course also the "content-encoding" has to be added to the "memorize_headers" option.