Generating module.cache.js instead of module.nocache.js

[Alexander Orlov]

The default behavior of GWT is to generate the module.nocache.js versions. But how can I generate a module.cache.js version of a module? I've found some information about this issue but it seems to be obsolete. Also what does cache.js mean exactly? Can't I achieve the same result by adding *.nocache.js to HTML5's App Cache?

[Thomas Broyer]

*.cache.* and *.nocache.* are just naming conventions adopted by GWT to help setup the "perfect caching" configurations.

If you enable caching for the *.nocache.js file, then you explicitly allow intermediate servers/proxies, and browsers, to serve/use a possibly obsolete version of you app, without necessarily checking for a fresher on at your server. That means your servlets have to be prepared receiving requests from such versions even after you pushed an update to your server.

[Alexander Orlov]

On Friday, September 16, 2011 12:00:59 PM UTC+2, Thomas Broyer wrote:

*.cache.* and *.nocache.* are just naming conventions adopted by GWT to help setup the "perfect caching" configurations.

Really useful insights!

 

If you enable caching for the *.nocache.js file, then you explicitly allow intermediate servers/proxies, and browsers, to serve/use a possibly obsolete version of you app, without necessarily checking for a fresher on at your server. That means your servlets have to be prepared receiving requests from such versions even after you pushed an update to your server.

That's also what I had in mind. I just wondered why so many Google apps use the *.cache.js version. Ok, if the content ist pretty static and for a very high number of reqs/s it may be a viable solution.

[Thomas Broyer]

AFAICT, most Google Apps do on the server side what the *.nocache.js does on the client side in a "default" setup (i.e. choose the right permutation, i.e. the right *.cache.* file, to load for a given user agent, locale, whatever combination).

They use the xsiframe (or actually probably a custom linker, similar to xsiframe) that generates *.cache.js instead of *.cache.html so they can include a <script src="…"></script> to it in the generated HTML. I believe their linker generates some sort of JSP code or similar, instead of the *.nocache.js that the other linkers output.

That way, they save one round-trip to the server, and given that the host page is already non-cacheable due to authentication, they don't lose anything (in a "default" setup, the host page is a static HTML page, so you can generally enable some level of caching on it; what matters being that the *.nocache.js is non-cacheable).