001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005// http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.internal.services;
014
015import org.apache.tapestry5.beanmodel.services.*;
016import org.apache.tapestry5.commons.util.UnknownValueException;
017import org.apache.tapestry5.http.services.Request;
018import org.apache.tapestry5.internal.InternalConstants;
019import org.apache.tapestry5.internal.structure.Page;
020import org.apache.tapestry5.services.ComponentEventRequestParameters;
021import org.apache.tapestry5.services.ComponentRequestFilter;
022import org.apache.tapestry5.services.ComponentRequestHandler;
023import org.apache.tapestry5.services.PageRenderRequestParameters;
024
025import java.io.IOException;
026
027/**
028 * A filter, used only in production mode, that does a "pre-flight check" that the indicated component
029 * actually exists. If it does not, then the handling of the component event is aborted and other
030 * hooks will ensure that request ultimately becomes a 404.
031 *
032 * @since 5.4
033 */
034public class ProductionModeUnknownComponentFilter implements ComponentRequestFilter
035{
036    private final Request request;
037
038    private final RequestPageCache cache;
039
040    public ProductionModeUnknownComponentFilter(Request request, RequestPageCache cache)
041    {
042        this.request = request;
043        this.cache = cache;
044    }
045
046    @Override
047    public void handleComponentEvent(ComponentEventRequestParameters parameters, ComponentRequestHandler handler) throws IOException
048    {
049        Page containerPage = cache.get(parameters.getContainingPageName());
050
051        try
052        {
053            containerPage.getComponentElementByNestedId(parameters.getNestedComponentId());
054
055            handler.handleComponentEvent(parameters);
056
057        } catch (UnknownValueException ex)
058        {
059            request.setAttribute(InternalConstants.REFERENCED_COMPONENT_NOT_FOUND, true);
060        }
061    }
062
063    @Override
064    public void handlePageRender(PageRenderRequestParameters parameters, ComponentRequestHandler handler) throws IOException
065    {
066        // Pass these through to the default handler.
067        handler.handlePageRender(parameters);
068    }
069}