Allow GWC publishing formats to be contributed by a properties file

src/gwc/src/main/java/org/geoserver/gwc/GWC.java

@@ -9,11 +9,14 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Throwables.getRootCause;
 import static com.google.common.base.Throwables.propagate;
+import static com.google.common.collect.Iterators.forEnumeration;
+import static com.google.common.collect.Lists.newArrayList;
 import static org.geowebcache.grid.GridUtil.findBestMatchingGrid;
 import static org.geowebcache.seed.GWCTask.TYPE.TRUNCATE;
 
 import java.io.IOException;
 import java.lang.reflect.Method;
+import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -22,6 +25,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Properties;
 import java.util.Set;
 import java.util.TreeSet;
 import java.util.logging.Level;
@@ -39,6 +43,7 @@
 import org.geoserver.catalog.LayerGroupInfo;
 import org.geoserver.catalog.LayerInfo;
 import org.geoserver.catalog.NamespaceInfo;
+import org.geoserver.catalog.PublishedType;
 import org.geoserver.catalog.ResourceInfo;
 import org.geoserver.catalog.StyleInfo;
 import org.geoserver.gwc.config.GWCConfig;
@@ -121,6 +126,7 @@
 import org.springframework.context.ApplicationContextAware;
 
 import com.google.common.base.Predicate;
+import com.google.common.base.Splitter;
 import com.google.common.base.Throwables;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Sets;
@@ -2059,4 +2065,62 @@ public void setApplicationContext(ApplicationContext applicationContext) throws
         this.applicationContext = applicationContext;
     }
 
+    /**
+     * Returns the list of {@link MimeType#getFormat() MIME Type formats} advertised as valid for
+     * caching for the given type of published kind of layer.
+     * <p>
+     * Handles the case where some tile formats may be appropriate for vector layers but not for
+     * raster layers, or vice-versa.
+     * <p>
+     * Loads all resources in the classpath named
+     * {@code /org/geoserver/gwc/advertised_formats.properties} so other modules can contribute
+     * advertised formats without introducing unneeded dependencies.
+     * <p>
+     * {@code /org/geoserver/gwc/advertised_formats.properties} has entries for the following keys,
+     * whose values are a comma separated list of GWC MIME format names: {@code formats.vector},
+     * {@code formats.raster}, and {@code formats.group}
+     * 
+     * @param type the kind of geoserver published resource the tile layer is tied to.
+     * @return the set of advertised mime types for the given kind of tile layer origin
+     */
+    public Set<String> getAdvertisedCachedFormats(final PublishedType type) {
+
+        final String resourceName = "org/geoserver/gwc/advertised_formats.properties";
+        final String formatsKey;
+
+        switch (type) {
+        case VECTOR: // local vector layer
+        case REMOTE: // remote WFS
+            formatsKey = "formats.vector";
+            break;
+        case RASTER: // local raster layer
+        case WMS: // remote WMS raster
+            formatsKey = "formats.raster";
+            break;
+        case GROUP:
+            formatsKey = "formats.layergroup";
+            break;
+        default:
+            throw new IllegalArgumentException("Unknown published type: " + type);
+        }
+        Set<String> formats = new TreeSet<String>();
+        try {
+            ClassLoader classLoader = getClass().getClassLoader();
+            ArrayList<URL> urls = newArrayList(forEnumeration(classLoader.getResources(resourceName)));
+            for (URL url : urls) {
+                Properties props = new Properties();
+                props.load(url.openStream());
+                String commaSeparatedFormats = props.getProperty(formatsKey);
+                if (commaSeparatedFormats != null) {
+                    List<String> splitToList = Splitter.on(",").omitEmptyStrings().trimResults()
+                            .splitToList(commaSeparatedFormats);
+                    formats.addAll(splitToList);
+                }
+            }
+        } catch (IOException e) {
+            throw Throwables.propagate(e);
+        }
+        return formats;
+    }
+
 }

src/gwc/src/main/resources/org/geoserver/gwc/advertised_formats.properties

@@ -0,0 +1,10 @@
+#
+# A resource meant to contribute GWC tile encoding formats to the
+# configuration UI through the org.geoserver.gwc.GWC.getAdvertisedCachedFormats(PublishedType)
+# method, so that format options can be contributed by other modules
+# without introducing unneeded dependencies. Multiple resources names like this
+# one can exist in other jar files and GWC will take care of loading them
+#
+formats.vector = image/png, image/png8, image/jpeg, image/gif
+formats.raster = image/png, image/png8, image/jpeg, image/gif
+formats.layergroup = image/png, image/png8, image/jpeg, image/gif

src/web/gwc/src/main/java/org/geoserver/gwc/web/layer/GeoServerTileLayerEditor.java

@@ -39,6 +39,8 @@
 import org.geoserver.catalog.LayerGroupInfo;
 import org.geoserver.catalog.LayerInfo;
 import org.geoserver.catalog.MetadataMap;
+import org.geoserver.catalog.PublishedInfo;
+import org.geoserver.catalog.PublishedType;
 import org.geoserver.catalog.ResourceInfo;
 import org.geoserver.catalog.impl.ModificationProxy;
 import org.geoserver.gwc.ConfigurableBlobStore;
@@ -58,6 +60,7 @@
 import org.geowebcache.storage.blobstore.memory.CacheProvider;
 
 import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
 
 /**
  * Edit panel for a {@link GeoServerTileLayerInfo} (used to edit caching options for both
@@ -140,7 +143,7 @@ class GeoServerTileLayerEditor extends FormComponentPanel<GeoServerTileLayerInfo
      * @param tileLayerModel must be a {@link GeoServerTileLayerInfoModel}
      */
     public GeoServerTileLayerEditor(final String id,
-            final IModel<? extends CatalogInfo> layerModel,
+            final IModel<? extends PublishedInfo> layerModel,
             final IModel<GeoServerTileLayerInfo> tileLayerModel) {
         super(id);
         checkArgument(tileLayerModel instanceof GeoServerTileLayerInfoModel);
@@ -150,7 +153,7 @@ public GeoServerTileLayerEditor(final String id,
         final GWC mediator = GWC.get();
         final IModel<String> createTileLayerLabelModel;
 
-        final CatalogInfo info = layerModel.getObject();
+        final PublishedInfo info = layerModel.getObject();
         final GeoServerTileLayerInfo tileLayerInfo = tileLayerModel.getObject();
 
         if (info instanceof LayerInfo) {
@@ -254,8 +257,8 @@ public GeoServerTileLayerEditor(final String id,
         cacheFormats.setLabel(new ResourceModel("cacheFormats"));
         configs.add(cacheFormats);
 
-        final List<String> formats = Arrays.asList("image/png", "image/png8", "image/jpeg",
-                "image/gif", "application/json;type=topojson");
+        final List<String> formats;
+        formats = Lists.newArrayList(GWC.get().getAdvertisedCachedFormats(info.getType()));
 
         ListView<String> cacheFormatsList = new ListView<String>("cacheFormats", formats) {
             private static final long serialVersionUID = 1L;