有没有办法让GoogleImageProxy荣幸Cache-Control / expiration头文件?

我突然被谷歌的图像代理服务器的请求淹没,看起来像下面这样:

66.249.81.250 - - [04/May/2015:06:55:54 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.93.170 - - [04/May/2015:06:56:31 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.93.170 - - [04/May/2015:06:56:31 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.83.202 - - [04/May/2015:06:56:44 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 64.233.173.224 - - [04/May/2015:06:56:45 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.81.244 - - [04/May/2015:06:56:49 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.83.196 - - [04/May/2015:06:57:19 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 64.233.173.218 - - [04/May/2015:06:57:27 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.83.208 - - [04/May/2015:06:57:30 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.88.250 - - [04/May/2015:06:57:32 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 66.249.88.252 - - [04/May/2015:06:57:32 +0000] "GET /images/image_1.jpg HTTP/1.1" 200 93394 "-" "Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko Firefox/11.0 (via ggpht.com GoogleImageProxy)" 

正如你所看到的,我的服务器(Apache 2.2.22)正在响应满200,并为每个请求重新发送图像。 当我在浏览器中做出同样的请求时,我得到了一个304响应和以下头文件:

 Cache-Control:max-age=5184000 Date:Mon, 04 May 2015 06:43:00 GMT Expires:Fri, 03 Jul 2015 06:43:00 GMT 

是否有一些原因,谷歌图像代理不尊重这些,有什么我可以做的,除了打开像Cloudflare之类的东西,希望最好的? 我明白…

Apache日志充斥着连接 – “(通过ggpht.com GoogleImageProxy)”

…这是“正常”的stream量,但我不乐意每次都要重新提供整个100kb的文件。

Goolge图像代理正在caching。
您可以通过将图像embedded到电子邮件中并将其发送到您可以控制的Gmail帐户来轻松进行testing。
重新加载页面几次(当然,丢弃caching)。
caching命中,您的服务器将不会收到任何请求。

目前还不清楚是否同一个caching的URL /文件被提供给多个用户。
也许这就是你所看到的。

但无论如何:如果你发送一封电子邮件给10个人,并在其中embedded一个图像,你应该期望你的服务器不得不提供10个请求。
我不明白这是如何泛滥。