Thanks, Scott, Yeah, I thought it was going to be complicated ;-/ I actually was looking at ASP and PHP code to see if I could write something in Witango that would kind of do the same thing.
I was looking at this from a Googlebot point of view. When Gbot comes, if the requested page hasn't been modified since the last request it won't crawl the page. Google recommends that you use this... "You should configure your server to return this response (called the If-Modified-Since HTTP header) when a page hasn't changed since the last time the requestor asked for it. This saves you bandwidth and overhead because your server can tell Googlebot that a page hasn't changed since the last time it was crawled." 'Dude -----Original Message----- From: Scott Cadillac [mailto:[EMAIL PROTECTED] Sent: Friday, August 22, 2008 9:51 AM To: [email protected] Subject: Re: Witango-Talk: 304 last-modified Hey Dude, Unfortunately HTTP caching takes a lot more consideration than just globally setting a custom HTTP response header. When you set a custom header for caching purposes, this process is entirely dependent on receiving some specific request HTTP header properties (i.e., If-Modified-Since and/or If-None-Match), in order to conditionally set a corresponding expiry date, an ETag number and a 304 response (for the subsequent responses), as opposed to the custom 200 response (on the first response). And depending on the version of tango you are running - you may not have access to these HTTP properties. In addition, HTTP caching is managed by matching the entire URL of the file in question, this includes the argument names and values, so if your GET arguments are changing, then your caching is overridden. POST requests generally always override cache checks as well. And of course it should be mentioned that although browsers and proxies do adhere to the HTTP standards, these applications and devices are sometimes unpredictable as to "when" they implement cache rules. I've built systems with HTTP caching, and I hope I can save you some time by giving you some advice - don't bother. The headache, unpredictability and limited results is usually not worth it. There'll be times where you can easily waste hours chasing your code in circles just to discover that all the bugs and weird behavior is the result of something happening off the server (where you have no control). I would recommend you pursue methods for caching whatever essential data you need in memory on the Server to save on performance issues - or check out load balancing. Or possibly an appliance of some kind that handles the caching outside of your server. And please note, your tango code example is for deliberately turning "off" caching. I hope this helps, good luck. Scott, On Aug-22-2008, at 10:55 AM, WebDude wrote: > Hi All, > > I am a bit confused as to how to implement a caching scheme in which I > can show whether or not a page has been updated or not. This is for a > forum that stores the last update by date. I would like to change the > response http to show the last-modified date if possible. > Unfortunately, I am a novice on http headers and would like some help > on how to implement this. If I set the expiry to > > <@ASSIGN Local$httpHeader VALUE="Content-Type: text/html<@CRLF>Cache- > Control: no-cache, max-age=0, must-revalidate,proxy > revalidate<@CRLF>Pragma: no- > cache<@CRLF><@USERREFERENCECOOKIE><@CRLF>"> > > Will this generat what I need for the request? I am looking for the > reponse to be something like this... > > HTTP/1.0 200 OK > Server: Microsoft-IIS/5.0 > Content-Location: http://www.xyz.taf > Date: Fri, 22 Aug 2008 18:22:39 GMT > Content-Type: text/html > Accept-Ranges: bytes > Last-Modified: Wed, 020 Aug 2008 13:30:23 GMT > ETag: "801395163ec21:8a9" > Content-Length: 751 > > And I am confused as to the ETag. > > Can I set this globally for all tafs? or would that really take a > performance hit? > > Can someone shed some light on this, please? > > Thanks! > > > > ______________________________________________________________________ > __ TO UNSUBSCRIBE: Go to http://www.witango.com/developer/maillist.taf ________________________________________________________________________ TO UNSUBSCRIBE: Go to http://www.witango.com/developer/maillist.taf ________________________________________________________________________ TO UNSUBSCRIBE: Go to http://www.witango.com/developer/maillist.taf
