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

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Here is the source code for org.ebayopensource.scc.cache.CacheResultVerifier.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.FullHttpResponse;
import io.netty.handler.codec.http.HttpHeaders;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class CacheResultVerifier {
    private static boolean s_vaStrict = Boolean.valueOf(System.getProperty("coldCache.verifyCacheResult.strict"));
    private static Set<String> s_tolerantHeaders = new HashSet<>(Arrays.asList(new String[] { "DATE" }));
    protected FullHttpRequest m_req;
    protected FullHttpResponse m_cacheResp;
    protected String m_key;

    public CacheResultVerifier(String key, FullHttpRequest cr, FullHttpResponse cacheResp) {
        this.m_key = key;
        this.m_req = cr;
        this.m_cacheResp = cacheResp;
    }

    public CacheVerifiedResult fetchResult(FullHttpResponse actualResp) {
        CacheVerifiedResult result = new CacheVerifiedResult();
        String cause = match(actualResp);
        result.cause = cause;
        result.key = m_key;
        result.result = (cause == null);
        return result;
    }

    protected String match(FullHttpResponse actualResp) {
        String eTag = HttpHeaders.getHeader(m_cacheResp, "ETag");
        String actualETag = HttpHeaders.getHeader(actualResp, "ETag");
        if (actualETag != null && actualETag.equals(eTag)) {
            return null;
        } else if (actualETag != null && !actualETag.equals(eTag)) {
            return String.format("ETag mismatch: cache - %s; actual - %s", eTag, actualETag);
        } else if (actualETag == null && eTag == null) {
            // match status code
            if (actualResp.getStatus().compareTo(m_cacheResp.getStatus()) != 0) {
                return String.format("Status code mismatch: cache - %s; actual - %s",
                        m_cacheResp.getStatus().code(), actualResp.getStatus().code());
            }

            // match headers
            HttpHeaders actualHeaders = actualResp.headers();
            HttpHeaders headers = m_cacheResp.headers();
            List<String> mh = new ArrayList<>();// mismatched headers
            checkHeaderDiffer(actualHeaders, headers, mh);
            if (!mh.isEmpty()) {
                return String.format("Mismatched headers: %s", mh.toString());
            }
            checkHeaderDiffer(headers, actualHeaders, mh);
            if (!mh.isEmpty()) {
                return String.format("Mismatched headers: %s", mh.toString());
            }

            // match entity
            ByteBuf actualContent = actualResp.content();
            ByteBuf content = m_cacheResp.content();
            int len = actualContent.readableBytes();
            if (len != content.readableBytes()) {
                return "Mismatched body input stream.";
            }

            for (int i = 0; i < len; i++) {
                if (actualContent.getByte(i) != content.getByte(i)) {
                    return "Mismatched body input stream.";
                }
            }
        }
        return null;
    }

    private void checkHeaderDiffer(HttpHeaders headers1, HttpHeaders headers2, List<String> mh) {
        for (String headerName : headers1.names()) {
            if (!s_vaStrict && s_tolerantHeaders.contains(headerName.toUpperCase())) {
                continue;
            }
            String v1 = headers1.get(headerName);
            String v2 = headers2.get(headerName);
            if (!v1.equals(v2)) {
                mh.add(headerName);
            }
        }
    }

}