Molindo Techblog

/* $Revision$ */

/* $Revision: 1234 $ */

protected void init()
{
  // snip
  mountVersionedResource("/css/", CssScope.class, "all.css");
}
 
protected ResourceReference mountVersionedResource(String prefix,
  Class scope, String path)
{
  String unversionedPath = prefix + path;
  String versionedPath = prefix + getVersionedPath(scope, path);
 
  ResourceReference ref = getResourceRef(scope, path);
  mountSharedResource(versionedPath, ref.getSharedResourceKey());
 
  // redirect all.css to all-1234.css, just to be safe
  if (!unversionedPath.equals(versionedPath))
  {
    mount(new RedirectStrategy(unversionedPath, WebPage.class,
      null, versionedPath));
  }
  return ref;
}
 
private final class RedirectStrategy
  extends BookmarkablePageRequestTargetUrlCodingStrategy
{
  private final String _redirectPath;
 
  private RedirectStrategy(String mountPath, Class pageClass,
    String pageMapName, String redirectPath)
  {
    super(mountPath, pageClass, pageMapName);
    _redirectPath = redirectPath;
  }
 
  public IRequestTarget decode(final RequestParameters params)
  {
    return new RedirectRequestTarget(_redirectPath);
  }
 
  String getVersionedPath(Class scope, String path){
    // snip: removed for simplicity, i'll provide code if desired
  }
 
  protected ResourceReference getResourceRef(Class scope,String path)
  {
    ResourceReference ref;
    if (path.endsWith(".js"))
    {
      ref = new ResourceReference(scope, path)
      {
        protected Resource newResource()
        {
          return new JavascriptPackageResource(scope,path,null,null)
          {
            protected int getCacheDuration()
            {
              return CACHE_DURATION;
            }
          };
        }
      };
    } else if (path.endsWith(".css")) {
      // snip: choose appropriate resource references
    }
    ref.bind(this);
    return ref;
  }
}

public MyPanel(String id)
{
  super(id);
  add(HeaderContributor.forCss(CssScope.class, "all.css"));
  // snip
}

Responses

1. victori says:
   

   August 20th, 2008 at 3:19 pm (#)

   Not sure if you know this but, you can also setup your resources with a GET parameter which will force the browser to re-download the file, for example:/css/foo.css?v=0.1 … foo.css?v=0.2

2. Stefan Fußenegger says:
   

   August 20th, 2008 at 3:31 pm (#)

   in deed, using parameters is just another way of creating a unique URL for a particular resource version. However, I’m not aware of a Wicket-way to do this. How would you do this? It could probably be done by changing getVersionedPath(..) in my implementation to return a different string, but that’s probably not what you meant.

3. Anonymous says:
   

   August 25th, 2008 at 9:18 am (#)

   Hi StefanI just write something about caching on my blog too, it goes well in hand with what you’ve written:http://ninomartinez.wordpress.com/2008/08/25/pump-your-java-with-caching/

4. Jörn Zaefferer says:
   

   August 27th, 2008 at 10:22 am (#)

   According to Steve Souders, putting the version into the filename has certain advantages.In that regards: Would you mind posting your getVersionedPath implementation?ThanksJörn

5. Stefan Fußenegger says:
   

   August 27th, 2008 at 10:49 am (#)

   Hi Nino, Jörn,Thanks for your comments and links.@Nino:Server-side and client-side go well in hand in deed. However, one should note that these are completely different topics.@Jörn;Here is my implementation: molindo.at/files/Version.java. It isn’t a valid Java class though, just some code snippets pasted together. Anyway, I hope it helps!Best regards, Stefan

6. Jörn Zaefferer says:
   

   August 27th, 2008 at 11:30 am (#)

   Thanks Stefan, that helps a lot!Yet missing are the methods getResourcePath and getResourceRef and the class CssScope – I have no idea what that does.

7. Bert says:
   

   April 2nd, 2009 at 8:47 am (#)

   Thank you. That helped a lot.

   After reading your post I came to this part of code:

   protected void mountVersionedResource(String prefix, Class scope, String path)
   {
   String versionedPath = prefix + getVersionedPath( path, System.currentTimeMillis() );
   ResourceReference ref = new ResourceReference(scope,path);
   mountSharedResource(versionedPath, ref.getSharedResourceKey());
   WebResource resource = new CompressedPackageResource(scope, versionedPath, null, null)
   {
   @Override
   protected int getCacheDuration()
   {
   return 3600 * 24 * 7; // one week
   }
   };
   getSharedResources().add(scope, path, null, null, resource);
   }

   protected String getVersionedPath(final String filePath, final long version)
   {
   return Strings.beforeLast(filePath, ‘.’) + “-” + version + “.” + Strings.afterLast(filePath, ‘.’);
   }

8. Todd says:
   

   July 12th, 2011 at 3:04 am (#)

   Hi Stefan,
   Thanks for your blog post. It was very helpful. I’m looking at doing something similar, exception I’m going to name the file names in the format of _sha256sum.. However, I would like to make this the default behavior for all requested components. I’ve overridden the ResourceLoader to calculate the sums for each resource as it’s loaded. However I can’t seem to find a global hook into resource creation short of an instantiation listener. Is there any other way to create the mapping for the resource without requiring the developer to call the custom code?

   Thanks,
   Todd

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