Fabio, We're achieving a good cache result by using mod_proxy and its built in proxy cache.
We have: Front servers that do caching and backservers that runs the tomcat. The fron servers runs apache and mod_proxy. Any request coming in to example www.foo.com/index.jsp is proxied through to the back hosts where another apache is listening on port 80. The apache on the back host uses mod_jk to connect to Tomcat which serves the page. mod_proxy on the fron hosts has a proxy cache which can be used to cache our jsp pages. There are some simple rules to follow when you want a jsp to be cached in a generic web cache (see HTTP protocol for details on web caches). We got it sorted so that a request that comes into the front hosts, will only result in a revalidation (If-Modified-Since) to the back hosts. The jsp page can be coded to deal with this type of request and can then tell the front hosts to serve the cached page or return a new one. Martin > -----Original Message----- > From: Fabio Salvi [mailto:[EMAIL PROTECTED]] > Sent: 29 January 2003 10:43 > To: [EMAIL PROTECTED] > Subject: Ap..cache > > > Hi all, > > recently I've been thinking about a way to implement a cache > mechanism in Apache-Tomcat interaction (e.g. ajp13). I'd be > really grateful if you gave me some suggestions or advice on > the matter. Below I shortly describe what I've built as a > kind of prototype. > > To sum up, I've modified mod_jk (win2000) in some points in > order to make it cache-aware. I've introduced in httpd.conf > the following directives: > > # > # normal jk directives > # > JkMount /*.jsp ajp13 > > #Cache extensions > JkCache on > JkCacheDirectory C:\cache > > This is, basically, the collaboration diagram I've implemented: > > . mod_jk intercepts request for /pippo/cachetest.jsp; > . mod_jk asks Tomcat, at the moment actually a WebApp > controller, for a list of dirty items in cache folder; > . then, mod_jk deletes dirty-bit pages in the cache; > . now mod_jk manages current request. If it finds the > page in the cache it returns static file to Apache. > . Otherwise it requires the resource back to the WebApp > controller. The latter knows if the page is to be cached and > puts a special tag on the byte stream in response, after > having dynamically built it; > . mod_jk receives the response and if it does contain the > above mentioned tag, mod_jk writes it in the cache folder > before sending it to Apache. If there's a query string, it'll > include it in the static resource name. > > The second and third steps are an overload respect to normal > interaction, but that permits to save a lot of elaborating > time and network roundtrips when you ask for a very heavy > resource (e.g a jsp which loads many non-volatile and quite > stable data from a db). All that seems to work > fine...According to your opinion is a worth-to-develop idea? > > Thanks in advance for your advise! > Fabio > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
