org.ebayopensource.scc.cache.RequestKeyGenerator.java Source code

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Here is the source code for org.ebayopensource.scc.cache.RequestKeyGenerator.java

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/*******************************************************************************
 * Copyright (c) 2016 eBay Software Foundation.
 *
 * 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.
 *******************************************************************************/
package org.ebayopensource.scc.cache;

import io.netty.buffer.ByteBuf;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpHeaders;
import io.netty.handler.codec.http.HttpMethod;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import org.ebayopensource.scc.cache.policy.CacheDecisionObject;
import org.ebayopensource.scc.config.AppConfiguration;
import org.ebayopensource.scc.util.Checksum;
import org.ebayopensource.scc.util.WildcardMatcher;

public class RequestKeyGenerator implements IKeyGenerator<FullHttpRequest> {

    private Set<String> m_skipHeaders;
    private AppConfiguration m_appConfig;
    private boolean m_uriMatchEnabled;
    private List<Map<String, Object>> m_uriMatchOnly;

    @SuppressWarnings("unchecked")
    public RequestKeyGenerator(AppConfiguration appConfig) {
        m_appConfig = appConfig;
        List<Object> list = appConfig.getList("requestKeyGenerator.skipHeaders");
        m_skipHeaders = new HashSet<>(list.size());
        for (Object obj : list) {
            if (obj != null) {
                m_skipHeaders.add(obj.toString());
            }
        }

        Object subConfig = m_appConfig.getConfig().get("uriMatchOnly");
        if (subConfig != null && subConfig instanceof List) {
            m_uriMatchOnly = (List<Map<String, Object>>) subConfig;
            m_uriMatchEnabled = !m_uriMatchOnly.isEmpty();
        }
    }

    @Override
    public String generateKey(FullHttpRequest req) {
        String rHash = getRequestHash(req);
        if (rHash == null) {
            return null;
        }

        String key = getRequestURI(req) + '|' + rHash;
        return key;
    }

    private String getRequestURI(FullHttpRequest request) {
        String uri = request.getUri();
        if (uri.startsWith("/")) {
            String host = HttpHeaders.getHost(request);
            if (host != null && !host.isEmpty()) {
                uri = "https://" + host + uri;
            }
        }
        return uri;
    }

    private String getRequestHash(FullHttpRequest request) {
        HttpHeaders headers = request.headers();
        String requestURI = getRequestURI(request);
        HttpMethod requestMethod = request.getMethod();
        Set<String> skipHeaders = m_skipHeaders;
        boolean skipRequestContent = m_uriMatchEnabled && WildcardMatcher.isPatternCanBeMatchedIn(m_uriMatchOnly,
                new CacheDecisionObject(requestURI, requestMethod.name()));
        if (skipRequestContent) {
            skipHeaders = new HashSet<>(m_skipHeaders);
            skipHeaders.add(HttpHeaders.Names.CONTENT_LENGTH.toUpperCase());
        }

        int uriHashcode = requestURI.hashCode();
        int methodHashCode = requestMethod.hashCode();
        List<Entry<String, String>> entries = headers.entries();
        List<String> hashList = new ArrayList<>();
        for (Iterator<Entry<String, String>> it = entries.iterator(); it.hasNext();) {
            Entry<String, String> entry = it.next();
            if (skipHeaders.contains(entry.getKey().toUpperCase())) {
                continue;
            }
            hashList.add(entry.getKey());
            hashList.add(entry.getValue());
        }

        int headersHashcode = hashList.hashCode();

        StringBuilder sb = new StringBuilder(4);
        sb.append(uriHashcode).append(methodHashCode).append(headersHashcode);

        if (!skipRequestContent) {
            ByteBuf content = request.content();
            sb.append(content.hashCode());
        }

        return Checksum.checksum(sb.toString());
    }

}