org.sakaiproject.jsf.app.SakaiViewHandlerWrapper.java Source code

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/**********************************************************************************
 * $URL$
 * $Id$
 **********************************************************************************
 *
 * Copyright (c) 2003, 2004, 2005, 2006, 2008 The Sakai Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ECL-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.jsf.app;

import java.io.IOException;
import java.util.Locale;

import javax.faces.FacesException;
import javax.faces.application.ViewHandler;
import javax.faces.application.ViewHandlerWrapper;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.sakaiproject.tool.api.Tool;
import org.sakaiproject.util.ResourceLoader;
import org.sakaiproject.util.Web;

/**
 * <p>
 * SakaiViewHandlerWrapper extends the basic ViewHandlerWrapper functionality
 * 
 * @author University of Murcia
 * @version $Revision$
 */
public class SakaiViewHandlerWrapper extends ViewHandlerWrapper {
    // TODO: Note, these two values must match those in jsf-tool's JsfTool

    /** Request attribute we set to help the return URL know what path we add (does not need to be in the URL. */
    public static final String URL_PATH = "sakai.jsf.tool.URL.path";

    /** Request attribute we set to help the return URL know what extension we (or jsf) add (does not need to be in the URL. */
    public static final String URL_EXT = "sakai.jsf.tool.URL.ext";

    /** Our log (commons). */
    private static Log M_log = LogFactory.getLog(SakaiViewHandler.class);

    /** The wrapped ViewHandler. */
    private ViewHandler m_wrapped = null;

    /** Resource bundle using current language locale. */
    private ResourceLoader rb;

    public SakaiViewHandlerWrapper(ViewHandler wrapped) {
        m_wrapped = wrapped;
        rb = new ResourceLoader();
    }

    @Override
    public ViewHandler getWrapped() {
        return m_wrapped;
    }

    public String getActionURL(FacesContext context, String viewId) {
        HttpServletRequest req = (HttpServletRequest) context.getExternalContext().getRequest();

        if (req.getAttribute(URL_EXT) == null) {
            // If the request didn't go through JsfTool (the JSF is accessed directly from its webapp, 
            // not as a Sakai tool), then don't do Sakai's special action URL handling.
            return getWrapped().getActionURL(context, viewId);
        }

        // get the path that got us here (from the tool's point of view)
        String path = viewId;

        // modify the path to remove things that were added by Sakai navigation to get here (prefix path, suffix extension)
        String prefix = (String) req.getAttribute(URL_PATH);
        if ((prefix != null) && path.startsWith(prefix))
            path = path.substring(prefix.length());

        Object extensions = req.getAttribute(URL_EXT);
        String[] exts = extensions instanceof String ? new String[] { (String) extensions } : (String[]) extensions;
        for (String ext : exts) {
            if ((ext != null) && path.endsWith(ext))
                path = path.substring(0, path.length() - ext.length());
        }

        // make sure the URL processing uses the Sakai, not Native the request object so we can get at the URL information setup by the invoker
        req.removeAttribute(Tool.NATIVE_URL);

        // form our return URL
        String rv = Web.returnUrl(req, path);

        // restore (if needed)
        req.setAttribute(Tool.NATIVE_URL, Tool.NATIVE_URL);

        M_log.debug("action url for view: " + viewId + " = " + rv);

        return rv;
    }

    /** Methods delegated to default ViewHandler */

    public Locale calculateLocale(FacesContext arg0) {
        return rb.getLocale();
    }

    public String calculateRenderKitId(FacesContext arg0) {
        return getWrapped().calculateRenderKitId(arg0);
    }

    public UIViewRoot createView(FacesContext arg0, String arg1) {
        UIViewRoot root = getWrapped().createView(arg0, arg1);

        if (root != null) {
            // restore messages
            MessageSaver.restoreMessages(arg0);
        }

        return root;
    }

    public String getResourceURL(FacesContext arg0, String arg1) {
        return getWrapped().getResourceURL(arg0, arg1);
    }

    public void renderView(FacesContext context, UIViewRoot root) throws IOException, FacesException {
        // SAK-20286 start
        // Get the request
        HttpServletRequest req = (HttpServletRequest) context.getExternalContext().getRequest();
        String requestURI = req.getRequestURI();
        // Make the attribute name unique to the request 
        String attrName = "sakai.jsf.tool.URL.loopDetect.viewId-" + requestURI;
        // Try to fetch the attribute
        Object attribute = req.getAttribute(attrName);
        // If the attribute is null, this is the first request for this view
        if (attribute == null) {
            req.setAttribute(attrName, "true");
        } else if ("true".equals(attribute)) { // A looping request is detected.
            HttpServletResponse res = (HttpServletResponse) context.getExternalContext().getResponse();
            // Send a 404
            res.sendError(404, "File not found: " + requestURI);
        }
        // SAK-20286 end
        getWrapped().renderView(context, root);
    }

    public UIViewRoot restoreView(FacesContext arg0, String arg1) {
        UIViewRoot root = getWrapped().restoreView(arg0, arg1);

        if (root != null) {
            // restore messages
            MessageSaver.restoreMessages(arg0);
        }

        return root;
    }

    public void writeState(FacesContext arg0) throws IOException {
        getWrapped().writeState(arg0);
    }

}