We're trying to force the client's browser to reload static files when they change. Currently, we have our build scripts automatically creating a new directory with the build timestamp and replace the content in the code to point to that directory.
However, I feel this is hardly an optimal solution. It forces the client browser to load every single file if a new build exists, even if only 1 file changed, and build time increases considerably by scanning every file and replace every static file reference.
I know we can also set the version when we declare files (something like < link src="blahblah.css?version=1.1" />), but this forces us to change all our code to include a version placeholder and still have our build scripts replacing it.
Is there a smarter way to do this? We're using Spring MVC. Is there any option in mvc:resources that I'm not aware of to do this without changing code? Or something on web.xml?
We're using tomcat. Is there a way to do this at server level? Would it help to use a cache like Varnish or something? Or these caches only allow to set expiry times and not check that the file changed? Bear in mind I'm not comfortable at all in server and cache configuration tasks.
I found out about this project https://code.google.com/p/modpagespeed/, but since it's far from my comfort zone, I'm struggling to understand capabilities and if this helps with what I want.
Anyone has any ideas? Thanks
You can use version as a query parameter, e.g. /resources/foo.js?_version=1.0.0. If you are using Maven, it is not that hard to get version information from /META-INF/maven/{groupId}/{artifactId}/pom.properties. Of course this will force reload all scripts with every new version... but new versions are probably not deployed that often.
Then it is always a good practice to properly set HTTP caching headers. <mvc:resources> should correctly handle Last-Modified header for you. And you can set cache-period to make browser check the for resource modifications more often.