AjaxProxyComponent.java

/*
 * (C) Copyright 2006-2009 Nuxeo SA (http://nuxeo.com/) and others.
 *
 * 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.
 *
 * Contributors:
 *     Nuxeo - initial API and implementation
 *
 * $Id$
 */

package org.nuxeo.ecm.platform.web.common.ajax.service;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.nuxeo.ecm.platform.web.common.requestcontroller.service.LRUCachingMap;
import org.nuxeo.runtime.model.ComponentInstance;
import org.nuxeo.runtime.model.DefaultComponent;

/**
 * Simple Runtime component to manage proxyable url configuration via Extension Points
 *
 * @author tiry
 */
public class AjaxProxyComponent extends DefaultComponent implements AjaxProxyService {

    public static final String PROXY_URL_EP = "proxyableURL";

    protected static final Map<String, ProxyableURLDescriptor> urlDescriptors = new HashMap<String, ProxyableURLDescriptor>();

    protected static final Map<String, ProxyURLConfigEntry> urlCache = new LRUCachingMap<String, ProxyURLConfigEntry>(
            250);

    protected static final ReentrantReadWriteLock cacheLock = new ReentrantReadWriteLock();

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

    @Override
    public void registerContribution(Object contribution, String extensionPoint, ComponentInstance contributor) {
        if (PROXY_URL_EP.equals(extensionPoint)) {
            ProxyableURLDescriptor desc = (ProxyableURLDescriptor) contribution;
            registerProxyURL(desc);
        } else {
            log.error("Unknown ExtensionPoint " + extensionPoint);
        }
    }

    protected void registerProxyURL(ProxyableURLDescriptor desc) {
        if (urlDescriptors.containsKey(desc.getName())) {
            urlDescriptors.get(desc.getName()).merge(desc);
        } else {
            urlDescriptors.put(desc.getName(), desc);
        }
    }

    public ProxyURLConfigEntry getConfigForURL(String targetUrl) {
        ProxyURLConfigEntry entry = null;

        try {
            cacheLock.readLock().lock();
            entry = urlCache.get(targetUrl);
        } finally {
            cacheLock.readLock().unlock();
        }
        if (entry == null) {
            entry = computeConfigForURL(targetUrl);
            try {
                cacheLock.writeLock().lock();
                urlCache.put(targetUrl, entry);
            } finally {
                cacheLock.writeLock().unlock();
            }
        }
        return entry;
    }

    public ProxyURLConfigEntry computeConfigForURL(String targetUrl) {
        for (ProxyableURLDescriptor desc : urlDescriptors.values()) {
            if (desc.isEnabled()) {
                Pattern pat = desc.getCompiledPattern();
                Matcher m = pat.matcher(targetUrl);
                if (m.matches()) {
                    return new ProxyURLConfigEntry(true, desc);
                }
            }
        }
        // return deny by default
        return new ProxyURLConfigEntry();
    }

}