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

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Here is the source code for org.ebayopensource.scc.cache.BaseResponseSerializer.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.HttpHeaders;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseStatus;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;

import org.ebayopensource.scc.cache.CacheResponse.CacheEntry;

public abstract class BaseResponseSerializer<T> implements ISerializer<CacheResponse, T> {

    public BaseResponseSerializer() {
        super();
    }

    protected abstract HttpResponse getHttpResponse(Object obj);

    protected abstract List<Entry<String, String>> getTrailingHeaders(Object obj);

    protected abstract ByteBuf[] getContent(Object obj);

    public CacheResponse serialize(Object obj) {
        if (!getType().isAssignableFrom(obj.getClass())) {
            return null;
        }
        CacheResponse cacheResp = createCacheResponse(getHttpResponse(obj));
        copyTrailingHeaders(cacheResp, getTrailingHeaders(obj));
        copyBody(cacheResp, getContent(obj));
        return cacheResp;
    }

    protected void copyBody(CacheResponse cacheResp, ByteBuf... chunks) {
        int totalSize = 0;
        for (ByteBuf c : chunks) {
            if (c.isReadable()) {
                totalSize += c.readableBytes();
            }
        }

        ByteBuffer nioBuffer = ByteBuffer.allocate(totalSize);
        for (ByteBuf c : chunks) {
            if (c.isReadable()) {
                c.getBytes(c.readerIndex(), nioBuffer);
            }
        }

        if (nioBuffer.hasArray()) {
            cacheResp.setContent(nioBuffer.array());
        }

        // reset Content-Length
        List<CacheEntry<String, String>> headers = cacheResp.getHeaders();
        for (Iterator<CacheEntry<String, String>> it = headers.iterator(); it.hasNext();) {
            CacheEntry<String, String> header = it.next();
            if (HttpHeaders.Names.CONTENT_LENGTH.equals(header.getKey())) {
                it.remove();
            }
        }
        headers.add(new CacheEntry<String, String>(HttpHeaders.Names.CONTENT_LENGTH, String.valueOf(totalSize)));
    }

    protected void copyTrailingHeaders(CacheResponse cacheResp, List<Entry<String, String>> trailingHeaders) {
        List<CacheEntry<String, String>> cacheTrailingHeaders = cacheResp.getTrailingHeaders();
        for (Entry<String, String> entry : trailingHeaders) {
            cacheTrailingHeaders.add(new CacheEntry<String, String>(entry.getKey(), entry.getValue()));
        }
    }

    protected CacheResponse createCacheResponse(HttpResponse resp) {
        String protocolVersion = resp.getProtocolVersion().text();
        HttpResponseStatus status = resp.getStatus();
        int code = status.code();
        String reasonPhrase = status.reasonPhrase();

        List<Entry<String, String>> headers = resp.headers().entries();
        List<CacheEntry<String, String>> cacheHeaders = new ArrayList<>(headers.size());
        for (Entry<String, String> entry : headers) {
            cacheHeaders.add(new CacheEntry<String, String>(entry.getKey(), entry.getValue()));
        }

        return new CacheResponse(protocolVersion, code, reasonPhrase, cacheHeaders,
                new ArrayList<CacheEntry<String, String>>());
    }

}