Hi Lasse, I'll take a look in the coming days!
Martin Grigorov Wicket Training and Consulting https://twitter.com/mtgrigorov On Wed, May 18, 2016 at 11:43 AM, Lars Törner <[email protected]> wrote: > Hi Martin! > > We have now implemented this solution and we're using bootstrap-less - > thanks for that! > > But we have a little problem... > The browser does not recognize when the css has changed, the cause seems to > be that the newly generated css is placed in a file with the same name as > before. The name has a hashsum in the name that is generated from the > less-file and the less file has not changed. > > What happens is: > A less-variable (put in a separate file) gets a new value. > This triggers the less compiler to re-generate css > The name of the file with generated css has the same name as before so the > browser decides to use its cached version instead. > > (I'm not the developer of this issue, but hopefully I got it right...) > > Any suggestions? > > Cheers > Lasse > > > > 2016-03-01 13:02 GMT+01:00 Lars Törner <[email protected]>: > > > Thanks for your quick answer Martin! We will look into your suggestions > > and get back to you if we have more questions! > > > > 2016-03-01 11:49 GMT+01:00 Martin Grigorov <[email protected]>: > > > >> Hi Lasse, > >> > >> I think the easiest would be to save the generated CSS in memory, e.g. > in > >> YourApplication. > >> Once you receive an update from the other system you should just delete > >> the > >> cache (entry). I guess you will have to use read lock when serving the > >> response and write lock when updating it. > >> Wicket uses AbstractResource#dataNeedsToBeWritten() > >> < > >> > https://github.com/apache/wicket/blob/ffa34c6bfbd2ccd8340e23ff1601edd3e0e941d6/wicket-core/src/main/java/org/apache/wicket/request/resource/AbstractResource.java#L433 > >> > > >> method to decide whether the client/browser has the latest version. I.e. > >> when the browser makes a request for the CSS you should first check > >> whether > >> there is a cached entry for this CSS file. If there is no such then > >> generate it, save it in the cache and serve it back. If there is such > >> cache > >> entry then let Wicket check its last modification time against the > request > >> header value for 'If-Modified-Since'. > >> > >> Additionally you may want to pre-build the CSS resources at application > >> start time, or even preserve the current build-time solution, so it is > >> faster for the first users of the application before any changes in the > >> variables. > >> I've had an issue with similar setup in the past - we were using CDN > >> (Akamai) and their request timed out while waiting for the Less > >> compilation. For requests from normal browsers this shouldn't be a > problem > >> though. > >> > >> You may also check Wicket Bootstrap Less > >> < > >> > https://github.com/l0rdn1kk0n/wicket-bootstrap/tree/master/bootstrap-less > >> >. > >> It is a module of Wicket-Bootstrap project but could be used without the > >> other modules. > >> It provides most of the features you need. You just need to see how to > >> plug > >> the update of the variables. > >> > >> Martin Grigorov > >> Wicket Training and Consulting > >> https://twitter.com/mtgrigorov > >> > >> On Tue, Mar 1, 2016 at 10:45 AM, Lars Törner <[email protected]> > >> wrote: > >> > >> > Hi! > >> > > >> > We would like to be able to set new colors in our gui at runtime, i.e. > >> > change the theme. > >> > We use less on component basis. To day we compile the less files to > css > >> at > >> > buildtime and these becom packacke resources. > >> > > >> > Now we would like to change the colors by altering the appropriate > >> > less-variables. We want to set the colors (just values as - > themeColor = > >> > #000000) in our legacy application. Our web app lives in another > >> > servletcontainer than the legacy applicaton, so one apporach is to > fetch > >> > the new colors by REST (for example check for new colors once a > minute) > >> and > >> > get them as json in our wicket-web-app. > >> > > >> > Now we're thinking of using dynamic resources. i.e. do not compile the > >> > less-files at build-time, instead generate css-files fom the less > files > >> > (hooking in a less-preprocessor) per component at runtime when > >> requested. > >> > > >> > We don't want to generate the css-resource and send it to the client > if > >> > it's already cached in browser and not updated on server. > >> > We don't want to generate the css if it has already been done for the > >> > component and new colors hasn't been set, i.e once a dynamic resource > is > >> > generated, a cached version should be given as response for all > clients > >> > that request the component. > >> > > >> > Now the question is if the right way to do this is by implementing a > >> > dynamic resource by extending AbstractResource and to cache the css > >> (output > >> > a css-file on disk?, cache in application?) when once generated? > >> > > >> > Any drawbacks? Performance issues? Is there a better way to do it? > >> > > >> > Cheers > >> > Lasse > >> > > >> > > > > >
