process timestamps at build time

src/main/java/com/commafeed/frontend/resources/TimestampProcessor.java

@@ -0,0 +1,29 @@
+package com.commafeed.frontend.resources;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.io.Writer;
+import java.util.Calendar;
+
+import org.apache.commons.io.IOUtils;
+
+import ro.isdc.wro.model.resource.Resource;
+import ro.isdc.wro.model.resource.ResourceType;
+import ro.isdc.wro.model.resource.SupportedResourceType;
+import ro.isdc.wro.model.resource.processor.ResourcePreProcessor;
+
+@SupportedResourceType(ResourceType.JS)
+public class TimestampProcessor implements ResourcePreProcessor {
+
+	private static final String NOW = ""
+			+ Calendar.getInstance().getTimeInMillis();
+
+	@Override
+	public void process(Resource resource, Reader reader, Writer writer)
+			throws IOException {
+		String content = IOUtils.toString(reader);
+		content = content.replace("${timestamp}", NOW);
+		writer.write(content);
+	}
+
+}

src/main/java/com/commafeed/frontend/resources/WroAdditionalProvider.java

@@ -12,13 +12,14 @@ import com.google.api.client.util.Maps;
  * Build-time solution
  *
  */
-public class WroSassProvider implements ProcessorProvider {
+public class WroAdditionalProvider implements ProcessorProvider {
 
 	@Override
 	public Map<String, ResourcePreProcessor> providePreProcessors() {
 		Map<String, ResourcePreProcessor> map = Maps.newHashMap();
 		map.put("sassOnlyProcessor", new SassOnlyProcessor());
 		map.put("sassImport", new SassImportProcessor());
+		map.put("timestamp", new TimestampProcessor());
 		return map;
 	}
 

src/main/java/com/commafeed/frontend/resources/WroManagerFactory.java

@@ -15,6 +15,7 @@ public class WroManagerFactory extends ConfigurableWroManagerFactory {
 	protected void contributePreProcessors(Map<String, ResourcePreProcessor> map) {
 		map.put("sassOnlyProcessor", new SassOnlyProcessor());
 		map.put("sassImport", new SassImportProcessor());
+		map.put("timestamp", new TimestampProcessor());
 	}
 
 }