ThemeDirective.java

/*
 * (C) Copyright 2006-2009 Nuxeo SAS (http://nuxeo.com/) and contributors.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser General Public License
 * (LGPL) version 2.1 which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/lgpl.html
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * Contributors:
 *     Jean-Marc Orliaguet, Chalmers
 *
 * $Id$
 */

package org.nuxeo.theme.webengine.fm.extensions;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.net.URL;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.nuxeo.ecm.platform.rendering.fm.extensions.BlockWriter;
import org.nuxeo.ecm.webengine.WebEngine;
import org.nuxeo.ecm.webengine.model.WebContext;
import org.nuxeo.runtime.api.Framework;
import org.nuxeo.theme.ApplicationType;
import org.nuxeo.theme.Manager;
import org.nuxeo.theme.NegotiationDef;
import org.nuxeo.theme.negotiation.NegotiationException;
import org.nuxeo.theme.themes.ThemeException;
import org.nuxeo.theme.themes.ThemeManager;
import org.nuxeo.theme.types.TypeFamily;
import org.nuxeo.theme.webengine.negotiation.WebNegotiator;

import freemarker.core.Environment;
import freemarker.template.SimpleScalar;
import freemarker.template.Template;
import freemarker.template.TemplateDirectiveBody;
import freemarker.template.TemplateDirectiveModel;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;

/**
 * @author <a href="mailto:jmo@chalmers.se">Jean-Marc Orliaguet</a>
 */
public class ThemeDirective implements TemplateDirectiveModel {

    private static final Log log = LogFactory.getLog(ThemeDirective.class);

    private final Map<URL, String> cachedThemes = new HashMap<URL, String>();

    private final Map<URL, Long> lastRefreshedMap = new HashMap<URL, Long>();

    public void execute(Environment env, Map params, TemplateModel[] loopVars,
            TemplateDirectiveBody body) throws TemplateException, IOException {

        if (loopVars.length != 0) {
            throw new TemplateModelException(
                    "This directive doesn't allow loop variables.");
        }
        if (body == null) {
            throw new TemplateModelException("Expecting a body");
        }

        WebContext ctx = WebEngine.getActiveContext();
        if (ctx == null) {
            throw new IllegalStateException("Not In a Web Context");
        }

        String strategy = null;
        SimpleScalar strategyModel = (SimpleScalar) params.get("strategy");
        if (strategyModel != null) {
            strategy = strategyModel.getAsString();
        }

        final URL themeUrl = getThemeUrlAndSetupRequest(ctx, strategy);
        if (themeUrl == null) {
            return;
        }

        String rendered = "";
        try {
            rendered = renderTheme(themeUrl);
        } catch (ThemeException e) {
            log.error("Theme rendering failed", e);
            return;
        }

        // Render <@block> content
        BlockWriter writer = (BlockWriter) env.getOut();
        writer.setSuppressOutput(true);
        body.render(writer);
        writer.setSuppressOutput(false);

        // Apply the theme template
        BufferedReader reader = new BufferedReader(new StringReader(rendered));
        Template tpl = new Template(themeUrl.toString(), reader,
                env.getConfiguration(), env.getTemplate().getEncoding());
        env.include(tpl);

        reader.close();
    }

    public String renderTheme(URL themeUrl) throws ThemeException {
        if (!needsToBeRefreshed(themeUrl) && cachedThemes.containsKey(themeUrl)) {
            return cachedThemes.get(themeUrl);
        }
        String result = ThemeManager.renderElement(themeUrl);
        if (result != null) {
            cachedThemes.put(themeUrl, result);
            lastRefreshedMap.put(themeUrl, new Date().getTime());
        }
        return result;
    }

    protected boolean needsToBeRefreshed(URL themeUrl) {
        if (themeUrl == null) {
            return false;
        }
        if (Framework.isDevModeSet()) {
            return true;
        }
        if (themeUrl.getProtocol().equals("nxtheme")) {
            Long lastRefreshed = lastRefreshedMap.get(themeUrl);
            if (lastRefreshed == null) {
                lastRefreshed = 0L;
            }
            try {
                if (themeUrl.openConnection().getLastModified() >= lastRefreshed) {
                    return true;
                }
            } catch (IOException e) {
                return false;
            }
        }
        return false;
    }

    private static URL getThemeUrlAndSetupRequest(WebContext context,
            String strategy) throws IOException {
        HttpServletRequest request = context.getRequest();
        URL themeUrl = (URL) request.getAttribute("org.nuxeo.theme.url");
        if (themeUrl != null) {
            return themeUrl;
        }

        final ApplicationType application = (ApplicationType) Manager.getTypeRegistry().lookup(
                TypeFamily.APPLICATION, context.getModulePath(),
                context.getModule().getName());

        if (application == null) {
            log.error(getErrorMessage("Application not set for: ", context));
            return null;
        }

        final NegotiationDef negotiation = application.getNegotiation();
        if (negotiation == null) {
            log.error(getErrorMessage("Negotiation not set for: ", context));
            return null;
        }

        request.setAttribute("org.nuxeo.theme.default.theme",
                negotiation.getDefaultTheme());
        request.setAttribute("org.nuxeo.theme.default.engine",
                negotiation.getDefaultEngine());
        request.setAttribute("org.nuxeo.theme.default.perspective",
                negotiation.getDefaultPerspective());
        if (strategy == null) {
            strategy = negotiation.getStrategy();
        }

        if (strategy == null) {
            log.error(getErrorMessage("Negotiation strategy not set for: ",
                    context));
            return null;
        }

        try {
            final String spec = new WebNegotiator(strategy, context, request).getSpec();
            themeUrl = new URL(spec);
        } catch (NegotiationException e) {
            log.error(getErrorMessage(
                    "Could not get negotiation information for: ", context));
            return null;
        }

        request.setAttribute("org.nuxeo.theme.url", themeUrl);
        return themeUrl;
    }

    private static String getErrorMessage(String message, WebContext context) {
        return context.getModulePath() + "," + context.getModule().getName();
    }
}