话接上篇。 在发现经过squid的刷新请求头不带If-None-Match后，向squid-user发邮件询问。Amos回复如下：
On Mon, 02 Aug 2010 07:56:09 +0800, Gemmy chenryn@163.com wrote:
Hi~ > I have a nginx webserver adding the static-etags module and a > squid2.6.23 before the nginx. When I access to the nginx directly, I can > see the ETag in response header and If-None-Match in the request header > after refresh. But when I access to the squid, ETag header still > exist,If-None-Match header disappeared! > The squid.conf have most basic configuration items, nothing about cache. > Why does this happen?
Squid-2 has problems with If-None-Match. http://bugs.squid-cache.org/show_bug.cgi?id=2112
Please upgrade to Squid-2.7. It will behave a lot better regarding ETags in general and http://bugs.squid-cache.org/show_bug.cgi?id=2112 has some patches on 2.7 that you may want to try.
Amos
赶紧看看bug2112报告《Squid does not send If-None-Match tag for cache revalidation》，原来是http.c里，虽然 httpBuildRequestHeader定义了if-none-match，但却忘了定义接下来向源站发送的request-etags！ 重新下载squid2.7.9，编译完成后开始测试。访问动作和相应的日志记录如下： 第一次访问： 1280803634.566 65 59.108.42.242 TCP_MISS/200 19127 GET http://club.china.com/data/thread/1011/2716/16/81/5_1.html - ROUNDROBIN_PARENT/127.0.0.1 text/html “http://club.china.com/” “Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2” F5刷新有新内容： 1280803714.220 488 59.108.42.242 TCP_REFRESH_MISS/200 19127 GET http://club.china.com/data/thread/1011/2716/16/81/5_1.html - ROUNDROBIN_PARENT/127.0.0.1 text/html “http://club.china.com/” “Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2” F5刷新没新内容： 1280805207.149 3 59.108.42.242 TCP_REFRESH_HIT/304 309 GET http://club.china.com/data/threads/1011/1.html - ROUNDROBIN_PARENT/127.0.0.1 text/html “-“ “Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30)” 回复后返回新内容： 1280803803.696 20 59.108.42.242 TCP_REFRESH_HIT/200 19126 GET http://club.china.com/data/thread/1011/2716/16/81/5_1.html - ROUNDROBIN_PARENT/127.0.0.1 text/html “http://r.club.china.com/jsp/pub/replyAutoJump.jsp?url=http%3A%2F%2Fclub.china.com%2Fdata%2Fthread%2F1011%2F2716%2F16%2F81%2F5_1.html&forumid=1011&message=&picmessage=” “Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2” Ctrl+F5刷新： 1280803821.731 12 59.108.42.242 TCP_CLIENT_REFRESH_MISS/200 19127 GET http://club.china.com/data/thread/1011/2716/16/81/5_1.html - ROUNDROBIN_PARENT/127.0.0.1 text/html “http://r.club.china.com/jsp/pub/replyAutoJump.jsp?url=http%3A%2F%2Fclub.china.com%2Fdata%2Fthread%2F1011%2F2716%2F16%2F81%2F5_1.html&forumid=1011&message=&picmessage=” “Mozilla/5.0 (Windows; Windows NT 5.1; rv:2.0b2) Gecko/20100720 Firefox/4.0b2”
