net.hillsdon.reviki.web.dispatching.impl.DispatcherImpl.java Source code

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Here is the source code for net.hillsdon.reviki.web.dispatching.impl.DispatcherImpl.java

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/**
 * Copyright 2008 Matthew Hillsdon
 *
 * Licensed 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 net.hillsdon.reviki.web.dispatching.impl;

import static java.lang.String.format;

import java.io.IOException;
import java.net.URI;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.hillsdon.reviki.vc.NotFoundException;
import net.hillsdon.reviki.web.common.ConsumedPath;
import net.hillsdon.reviki.web.common.RequestAttributes;
import net.hillsdon.reviki.web.common.View;
import net.hillsdon.reviki.web.dispatching.Dispatcher;
import net.hillsdon.reviki.web.handlers.JumpToWikiUrl;
import net.hillsdon.reviki.web.handlers.ListWikis;
import net.hillsdon.reviki.web.redirect.RedirectView;
import net.hillsdon.reviki.web.urls.ApplicationUrls;
import net.hillsdon.reviki.web.vcintegration.RequestCompletedHandler;
import net.hillsdon.reviki.web.vcintegration.RequestLifecycleAwareManager;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class DispatcherImpl implements Dispatcher {

    private static final Log LOG = LogFactory.getLog(DispatcherServlet.class);

    private final ListWikis _list;

    private final WikiChoiceImpl _choice;

    private final JumpToWikiUrl _jumpToWiki;

    private final ApplicationUrls _applicationUrls;

    private final RequestLifecycleAwareManager _requestLifecycleAwareManager;

    private final RequestCompletedHandler _requestCompletedHandler;

    public DispatcherImpl(final ListWikis list, final WikiChoiceImpl choice, final JumpToWikiUrl jumpToWiki,
            final ApplicationUrls applicationUrls, final RequestLifecycleAwareManager requestLifecycleAwareManager,
            final RequestCompletedHandler requestCompletedHandler) {
        _list = list;
        _choice = choice;
        _jumpToWiki = jumpToWiki;
        _applicationUrls = applicationUrls;
        _requestLifecycleAwareManager = requestLifecycleAwareManager;
        _requestCompletedHandler = requestCompletedHandler;
    }

    public void handle(final HttpServletRequest request, final HttpServletResponse response)
            throws IOException, ServletException {
        request.setCharacterEncoding("UTF-8");
        request.setAttribute(ApplicationUrls.KEY, _applicationUrls);

        // We should be able to use request.getPathInfo() as it's documented as
        // having been correctly decoded by the container,
        // however Tomcat at least fails with UTF-8.
        final String requestPath = getStrippedPath(URI.create(request.getRequestURI()));
        final String contextPath = request.getContextPath();
        ConsumedPath path = new ConsumedPath(requestPath, contextPath);

        try {
            _requestLifecycleAwareManager.requestStarted(request);
            View view = handle(path, request, response);
            if (view != null) {
                view.render(request, response);
            }
        } catch (NotFoundException ex) {
            handleException(request, response, ex, false, "Could not find the file you were looking for.", 404);
        } catch (Exception ex) {
            handleException(request, response, ex, true, null, 500);
        } finally {
            _requestCompletedHandler.requestComplete();
        }
    }

    /**
     * Return the path segment of the URI with ;jssesionid parameter stripped of
     * (if necessary).
     *
     * The container handles the jsessionid for us but unfortunately Tomcat and
     * Jetty behave differently with respect to whether they include it in
     * getRequestURI().
     *
     * @param requestURI
     * @return requestURI with the ;jsessionid path segment parameter stripped.
     * @throws AssertionError
     */
    String getStrippedPath(final URI requestURI) {
        String path = requestURI.getPath();
        int jsessionId = path.indexOf(";jsessionid");
        if (jsessionId != -1) {
            path = path.substring(0, jsessionId);
        }
        return path;
    }

    // This should be moved out of here...
    private View handle(final ConsumedPath path, final HttpServletRequest request,
            final HttpServletResponse response) throws Exception {
        final String initial = path.next();
        // An internal hack (see index.jsp) to allow us to handle "/".
        if ("root".equals(initial)) {
            return new RedirectView(_applicationUrls.list());
        } else if ("pages".equals(initial)) {
            return _choice.handle(path, request, response);
        } else if ("jump".equals(initial)) {
            return _jumpToWiki.handle(path, request, response);
        } else if ("list".equals(initial)) {
            return _list.handle(path, request, response);
        }
        throw new NotFoundException();
    }

    private void handleException(final HttpServletRequest request, final HttpServletResponse response,
            final Exception ex, final boolean logTrace, final String customMessage, final int statusCode)
            throws ServletException, IOException {
        response.setStatus(statusCode);
        String user = (String) request.getAttribute(RequestAttributes.USERNAME);
        if (user == null) {
            user = "[none]";
        }
        String queryString = request.getQueryString();
        String uri = request.getRequestURI() + (queryString == null ? "" : "?" + queryString);
        String message = format("%s for user '%s' accessing '%s'.", ex.getClass().getSimpleName(), user, uri);
        if (logTrace) {
            LOG.error(message, ex);
        } else {
            LOG.warn(message, null);
        }
        request.setAttribute("exception", ex);
        request.setAttribute("customMessage", customMessage);
        request.getRequestDispatcher("/WEB-INF/templates/Error.jsp").forward(request, response);
    }

}