org.n52.oxf.util.web.GzipEnabledHttpClient.java Source code

Introduction

Here is the source code for org.n52.oxf.util.web.GzipEnabledHttpClient.java

Source

/**
 * Copyright (C) 2012-2015 52North Initiative for Geospatial Open Source
 * Software GmbH
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as publishedby the Free
 * Software Foundation.
 *
 * If the program is linked with libraries which are licensed under one of the
 * following licenses, the combination of the program with the linked library is
 * not considered a "derivative work" of the program:
 *
 *     - Apache License, version 2.0
 *     - Apache Software License, version 1.0
 *     - GNU Lesser General Public License, version 3
 *     - Mozilla Public License, versions 1.0, 1.1 and 2.0
 *     - Common Development and Distribution License (CDDL), version 1.0
 *
 * Therefore the distribution of the program linked with libraries licensed under
 * the aforementioned licenses, is permitted by the copyright holders if the
 * distribution is compliant with both the GNU General Public License version 2
 * and the aforementioned licenses.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU General Public License for more details.
 */
package org.n52.oxf.util.web;

import java.io.IOException;

import org.apache.http.Header;
import org.apache.http.HeaderElement;
import org.apache.http.HttpEntity;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.HttpResponse;
import org.apache.http.HttpResponseInterceptor;
import org.apache.http.client.entity.GzipDecompressingEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HttpContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class GzipEnabledHttpClient extends HttpClientDecorator {

    private static final Logger LOGGER = LoggerFactory.getLogger(GzipEnabledHttpClient.class);

    private static final String GZIP_ENCODING_VALUE = "gzip";

    private static final String ENCODING_HEADER_NAME = "Accept-Encoding";

    public GzipEnabledHttpClient(HttpClient httpclient) {
        super(httpclient);
        addGzipInterceptors(getHttpClientToDecorate());
    }

    private void addGzipInterceptors(DefaultHttpClient httpclient) {
        httpclient.addRequestInterceptor(new GzipRequestInterceptor());
        httpclient.addResponseInterceptor(new GzipResponseInterceptor());
    }

    private final class GzipResponseInterceptor implements HttpResponseInterceptor {
        public void process(HttpResponse response, HttpContext context) throws HttpException, IOException {
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                Header header = entity.getContentEncoding();
                if (header != null) {
                    HeaderElement[] codecs = header.getElements();
                    for (int i = 0; i < codecs.length; i++) {
                        if (codecs[i].getName().equalsIgnoreCase(GZIP_ENCODING_VALUE)) {
                            response.setEntity(new GzipDecompressingEntity(response.getEntity()));
                            return;
                        }
                    }
                }
            }
        }
    }

    private final class GzipRequestInterceptor implements HttpRequestInterceptor {
        public void process(HttpRequest request, HttpContext context) throws HttpException, IOException {
            if (!request.containsHeader(ENCODING_HEADER_NAME)) {
                LOGGER.trace("add gzip header.");
                request.addHeader(ENCODING_HEADER_NAME, GZIP_ENCODING_VALUE);
            }
        }
    }

}