org.sakaiproject.nakamura.files.pool.GetAlternativeContentPoolStreamServlet.java Source code

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Here is the source code for org.sakaiproject.nakamura.files.pool.GetAlternativeContentPoolStreamServlet.java

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/**
 * Licensed to the Sakai Foundation (SF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The SF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.sakaiproject.nakamura.files.pool;

import org.apache.commons.lang.StringUtils;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Service;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.request.RequestPathInfo;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
import org.sakaiproject.nakamura.api.files.FilesConstants;
import org.sakaiproject.nakamura.api.lite.ClientPoolException;
import org.sakaiproject.nakamura.api.lite.StorageClientException;
import org.sakaiproject.nakamura.api.lite.accesscontrol.AccessDeniedException;
import org.sakaiproject.nakamura.api.lite.content.Content;
import org.sakaiproject.nakamura.api.lite.content.ContentManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.HashSet;
import java.util.Set;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;

/**
 *
 */
@Service(value = DefaultServletDelegate.class)
@Component(immediate = true, enabled = true, metatype = true)
public class GetAlternativeContentPoolStreamServlet extends SlingSafeMethodsServlet
        implements DefaultServletDelegate {
    /**
     *
     */
    private static final Logger LOGGER = LoggerFactory.getLogger(GetAlternativeContentPoolStreamServlet.class);
    private static final long serialVersionUID = 6605017133790005483L;
    private static final Set<String> RESERVED_SELECTORS = new HashSet<String>();
    static {
        RESERVED_SELECTORS.add("selector-used-elsewhere");
    }

    public void doDelegateGet(SlingHttpServletRequest request, SlingHttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

    @Override
    protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response)
            throws ServletException, IOException {
        try {
            Resource resource = request.getResource();
            Content node = resource.adaptTo(Content.class);
            ContentManager contentManager = resource.adaptTo(ContentManager.class);
            String alternativeStream = getAlternativeStream(request);

            StreamHelper streamHelper = new StreamHelper();

            ServletContext sc = null;
            try {
                sc = getServletContext();
            } catch (IllegalStateException e) {
                LOGGER.debug(e.getMessage(), e);
            }

            streamHelper.stream(request, contentManager, node, alternativeStream, response, resource, sc);
        } catch (ClientPoolException e) {
            LOGGER.warn(e.getMessage(), e);
            throw new ServletException(e.getMessage(), e);
        } catch (StorageClientException e) {
            LOGGER.warn(e.getMessage(), e);
            throw new ServletException(e.getMessage(), e);
        } catch (AccessDeniedException e) {
            LOGGER.warn(e.getMessage(), e);
            throw new ServletException(e.getMessage(), e);
        }
    }

    private String getAlternativeStream(SlingHttpServletRequest request) {
        // be sure to keep this logic in sync with accepts
        RequestPathInfo rpi = request.getRequestPathInfo();
        Resource resource = request.getResource();
        String fileName = null;
        if (resource != null) {
            Content content = resource.adaptTo(Content.class);
            if (content != null) {
                fileName = (String) content.getProperty(FilesConstants.POOLED_CONTENT_FILENAME);
            }
        }
        String alternativeStream = null;
        String[] selectors = rpi.getSelectors();
        if ((selectors == null || selectors.length == 0) && rpi.getExtension() == null) {
            String[] lastPieces = parseResourcePath(rpi, fileName);
            if (lastPieces != null && lastPieces.length == 3 && !RESERVED_SELECTORS.contains(lastPieces[1])) {
                alternativeStream = lastPieces[1];
            }
        }
        return alternativeStream;
    }

    /**
     * Do not interfere with the default servlet's handling of streaming data, which kicks
     * in if no extension has been specified was specified in the request. (Sling servlet
     * resolution uses a servlet's declared list of "extensions" for score weighing, not for
     * filtering.)
     *
     * @see org.apache.sling.api.servlets.OptingServlet#accepts(org.apache.sling.api.SlingHttpServletRequest)
     */
    public boolean accepts(SlingHttpServletRequest request) {
        return getAlternativeStream(request) != null;
    }

    private String[] parseResourcePath(RequestPathInfo rpi, String fileName) {
        String[] lastPieces = null;
        String path = rpi.getResourcePath();
        int lastSlash = path.lastIndexOf('/');
        if (lastSlash > 0 && lastSlash < path.length() - 1) {
            String resourcePathEnding = path.substring(lastSlash + 1);
            if (fileName == null || !fileName.equals(resourcePathEnding)) {
                lastPieces = StringUtils.split(resourcePathEnding, ".", 4);
            }
        }
        return lastPieces;
    }
}