<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On 22 Sep 2010, at 22:10, Philipp Serafin wrote:</div><blockquote type="cite"><div>One disadvantage I think the version-in-URI approach has is that it's<br>completely transparent to the HTTP caching system. In particular, it<br>doesn't give caches any information about when a resource is expired.<br>This isn't really an issue if you really know for sure that your<br>resource in question only changes very rarely. However if you have a<br>resource that you would like to cache but where you cannot reliably<br>predict how fast it will change, this might become a problem. If your<br>resource changes too fast, this will clog up caches with dozens of old<br>versions which cannot be deleted because of their long-lived expiry<br>header. (Concrete example: Consider the avatar images of an internet<br>message board. Most users only set their avatar once when they register,<br>though a few may change them based on mood, holidays, etc.)<br></div></blockquote></div><div><br></div><div>Cached items can be cleared at any time, even if the cache headers indicate that they are still fresh. Browsers and caching proxies already do this.</div><div><br></div>Regards,<div><br></div><div>Adrian Sutton.<br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><span class="Apple-style-span" style="font-family: Verdana, Helvetica, Arial; font-size: 9px; ">______________________<br><font color="#07007E">Adrian Sutton, CTO<br></font><font color="#06007D">UK: +44 1 628 353 032 </font><font color="#07007E">US: +1 (650) 292 9659 x717<br></font><font color="#08007F">Ephox </font><font color="#0000FF"><u><a href="http://www.ephox.com/">http://www.ephox.com/</a></u></font><font color="#08007F"><br>Ephox Blogs<span class="Apple-converted-space"> </span></font><font color="#0000FF"><u><a href="http://people.ephox.com/">http://people.ephox.com/</a></u></font><font color="#08007F">, Personal Blog<span class="Apple-converted-space"> </span></font><font color="#0000FF"><u><a href="http://www.symphonious.net/">http://www.symphonious.net/</a></u></font></span></div><div><font class="Apple-style-span" color="#08007F" face="Verdana, Helvetica, Arial" size="1"><span class="Apple-style-span" style="font-size: 9px; "><br></span></font></div></div></span></div></span></div></span></div></span></div></span><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline">
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