DoNotCacheZeroSizeResponse.java

/*
 * #%L
 * ACS AEM Commons Bundle
 * %%
 * Copyright (C) 2015 Adobe
 * %%
 * 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.
 * #L%
 */package com.adobe.acs.commons.httpcache.rule.impl;

import com.adobe.acs.commons.httpcache.config.HttpCacheConfig;
import com.adobe.acs.commons.httpcache.engine.CacheContent;
import com.adobe.acs.commons.httpcache.rule.AbstractHttpCacheHandlingRule;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Service;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;

/**
 * ACS AEM Commons - HTTP Cache - Rule: Do not cache response which is size zero. Cancel the caching of response when it
 * has no bytes.
 */
@Component
@Service
public class DoNotCacheZeroSizeResponse extends AbstractHttpCacheHandlingRule {

    @Override
    public boolean onResponseCache(SlingHttpServletRequest request, SlingHttpServletResponse response,
                                   HttpCacheConfig cacheConfig, CacheContent cacheContent) {

        // Cancel the caching if no bytes in the sink.
        if ((null != cacheContent.getTempSink()) && (0 == cacheContent.getTempSink().length())) {
            return false;
        }
        return true;
    }
}