» CloudFlare ersetzt gegen Incapsula

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Hi,

all my static files have unlimited expiration so Incapsula doesn't need to check for changes. Is it possible that Incapsula ignores "pragma:no-cache" to avoid bypassing the incapsula cache?

regards,
Marc

Hello, Marc

If you would have specify an http header such as max-age or other cache related instructions,
your static resources can be cached without the need of the Proxies to learn what resources should be cached or not.

Thank you,
Incapsula Support Team

Hi,

all my images response with max-age, but this won't help if the request
header includes "pragma:no-cache". Then your proxy ignores max-age (this
is an usual setting of all proxies).

You can test it here:
http://www.maxrev.de/html/avatar-benchmark-cdn.html

Normal request time is 2-4 seconds. Now reload the page by hitting CTRL
+ F5 to force the browser to send the "pragma:no-cache"-header. Now the
loading time raises to 15-20 seconds.

This is because your server fetches the images again. It bypasses the
cache and probably overwrites the cached files. But this is unnecessary
and costs overall performance.

Only the webmaster should be able to reset the cache.

gruss / regards

Marc Gutt

Hello Marc,

Did you had a look at what my colleague wrote you on ticket #5110?

Thank you,
Incapsula Support Team

Hi Taly,

Yes, but the explanations in #5110 means something else. Dafna explained the different headers my server is able to set to activate / avoid Incapsula caching. I mean the request headers the visitor is sending.

There are three different locations that are able to set HTTP headers:

V = Visitor (my client)
P = Incapsula (your proxy)
S = maxrev (my server)

Explanation how the system works:

1. The first V requests a file. P fetches the file from S incl. the max-age header, saves it in the cache and forwards it to V.
2. The next V request a file. P has it already in the cache and serves it. No request is send to S.
3. The first V has deleted his browser cache and is requesting the file again. Same as in 2.)

Up this point everything is fine.

Now the problem:
3.) One V reloads the page by pressing F5 or CTRL+F5 (depends on browser) and now his http request header contains "pragma:no-cache". P fetches the file again from S incl. the max-age header, saves it in the cache and forwards it to V.

And this is not necessary. It costs your and my performance. The cache should be static as long max-age is not expired.

Note: Because of that all Performance-Tests through http://tools.pingdom.com/ are slow as well because their server send "pragma:no-cache" as well. Take a look:
(pingdom screenshot)

gruss / regards

Marc Gutt

Zitat

Hi Marc,

Well, even if you could control the proxy behaviour regarding the "pragma:no-cache" header, The maximum time length the proxies serves files from cache is, 5 minutes maximum & 20 seconds at minimum.

Thank you,
Incapsula Support Team

Mach mit!