001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.wicket.core.util.resource;
018
019import java.io.FileNotFoundException;
020import java.io.IOException;
021import java.io.InputStream;
022import java.net.URL;
023import java.time.Instant;
024import javax.servlet.ServletContext;
025import org.apache.wicket.Application;
026import org.apache.wicket.protocol.http.WebApplication;
027import org.apache.wicket.util.io.Connections;
028import org.apache.wicket.util.io.IOUtils;
029import org.apache.wicket.util.lang.Bytes;
030import org.apache.wicket.util.resource.AbstractResourceStream;
031import org.apache.wicket.util.resource.ResourceStreamNotFoundException;
032import org.slf4j.Logger;
033import org.slf4j.LoggerFactory;
034
035/**
036 * An {@link org.apache.wicket.util.resource.IResourceStream} that reads data from a file in the web application
037 *
038 * @author <a href="mailto:jbq@apache.org">Jean-Baptiste Quenot</a>
039 */
040public class WebExternalResourceStream extends AbstractResourceStream
041{
042        private static final Logger log = LoggerFactory.getLogger(WebExternalResourceStream.class);
043        private static final long serialVersionUID = 1L;
044
045        transient InputStream in;
046
047        /** the relative url of the external resource. */
048        private final String url;
049
050        /**
051         * Construct.
052         *
053         * @param url
054         *            the relative url of the external resource
055         */
056        public WebExternalResourceStream(String url)
057        {
058                if (url == null)
059                {
060                        throw new IllegalArgumentException("Argument url must be not null");
061                }
062
063                this.url = url;
064        }
065
066        @Override
067        public Bytes length()
068        {
069                return null;
070        }
071
072        @Override
073        public void close() throws IOException
074        {
075                // getInputStream() is not always called (WICKET-790)
076                IOUtils.close(in);
077        }
078
079        @Override
080        public Instant lastModifiedTime()
081        {
082                try
083                {
084                        final ServletContext context = ((WebApplication)Application.get()).getServletContext();
085                        final URL resourceURL = context.getResource(url);
086                        if (resourceURL == null)
087                        {
088                                throw new FileNotFoundException("Unable to find resource '" + url +
089                                        "' in the servlet context");
090                        }
091
092                        return Connections.getLastModified(resourceURL);
093                }
094                catch (IOException e)
095                {
096                        log.warn("failed to retrieve last modified timestamp", e);
097                        return null;
098                }
099        }
100
101        @Override
102        public String getContentType()
103        {
104                return WebApplication.get().getServletContext().getMimeType(url);
105        }
106
107        @Override
108        public InputStream getInputStream() throws ResourceStreamNotFoundException
109        {
110                final ServletContext context = ((WebApplication)Application.get()).getServletContext();
111
112                in = context.getResourceAsStream(url);
113                if (in == null)
114                {
115                        throw new ResourceStreamNotFoundException("The requested resource was not found: " +
116                                url);
117                }
118                return in;
119        }
120}