core/src/main/java/org/apache/sling/cms/core/internal/filters/LocaleFilter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.sling.cms.core.internal.filters;

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

import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.Value;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.jsp.jstl.core.Config;
import javax.servlet.jsp.jstl.fmt.LocalizationContext;

import org.apache.jackrabbit.api.JackrabbitSession;
import org.apache.jackrabbit.api.security.user.User;
import org.apache.jackrabbit.api.security.user.UserManager;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.cms.Site;
import org.apache.sling.cms.SiteManager;
import org.osgi.service.component.annotations.Component;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Sets the locale for the request based on the containing site.
 */
@Component(service = { Filter.class }, immediate = true, property = { "sling.filter.scope=request" })
public class LocaleFilter implements Filter {

    private static final Logger log = LoggerFactory.getLogger(LocaleFilter.class);

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // Nothing required
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {

        if (request instanceof SlingHttpServletRequest) {
            Locale locale = null;
            SlingHttpServletRequest slingRequest = (SlingHttpServletRequest) request;
            SiteManager mgr = slingRequest.getResource().adaptTo(SiteManager.class);
            if (mgr != null) {
                Site site = mgr.getSite();
                if (site != null) {
                    log.debug("Setting bundle for {}", site.getLocaleString());
                    locale = site.getLocale();
                } else {
                    log.trace("No site for {}", slingRequest);

                }
            } else {
                log.trace("No site manager found for {}", slingRequest);
            }

            if (locale == null) {
                locale = loadUserLocale(locale, slingRequest);
            }
            if (locale == null) {
                locale = Locale.getDefault(Category.DISPLAY);
            }
            setLocale(locale, slingRequest);
        }

        chain.doFilter(request, response);
    }

    private Locale loadUserLocale(Locale locale, SlingHttpServletRequest slingRequest) {
        try {
            JackrabbitSession session = (JackrabbitSession) slingRequest.getResourceResolver()
                    .adaptTo(Session.class);
            if (session != null) {
                final UserManager userManager = session.getUserManager();
                if (userManager.getAuthorizable(slingRequest.getResourceResolver().getUserID()) != null) {
                    User user = (User) userManager
                            .getAuthorizable(slingRequest.getResourceResolver().getUserID());
                    Value[] value = user.getProperty("profile/locale");
                    if (value != null && value.length > 0) {
                        locale = Locale.forLanguageTag(value[0].getString());
                    }
                }
            }
        } catch (RepositoryException e) {
            log.warn("Failed to load locale from current user", e);
        }
        return locale;
    }

    private void setLocale(Locale locale, SlingHttpServletRequest slingRequest) {
        ResourceBundle bundle = slingRequest.getResourceBundle(locale);
        Config.set(slingRequest, "javax.servlet.jsp.jstl.fmt.localizationContext",
                new LocalizationContext(bundle, slingRequest.getLocale()));
    }

    @Override
    public void destroy() {
        // Nothing required
    }

}