kmi.taa.core.SPARQLHTTPClient.java Source code

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Here is the source code for kmi.taa.core.SPARQLHTTPClient.java

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/*
 * (C) Copyright 2017 Shuangyan Liu
 * Shuangyan.Liu@open.ac.uk 
 * Knowledge Media Institute
 * The Open University, United Kingdom
 * 
 * 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 kmi.taa.core;

import java.io.IOException;
import java.nio.charset.StandardCharsets;

import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class SPARQLHTTPClient {

    public String httpGet(String url, String proxy) throws ClientProtocolException, IOException {
        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpGet httpget = new HttpGet(url);
        String responseBody;
        try {
            if (!proxy.isEmpty()) {
                String[] str = proxy.split(":");
                int port = Integer.parseInt(str[1]);
                HttpHost host = new HttpHost(str[0], port, str[2]);
                RequestConfig config = RequestConfig.custom().setProxy(host).build();
                httpget.setConfig(config);
            }

            ResponseHandler<String> responseHandler = new ResponseHandler<String>() {
                public String handleResponse(final HttpResponse response)
                        throws ClientProtocolException, IOException {
                    int status = response.getStatusLine().getStatusCode();
                    if (status >= 200 && status < 300) {
                        try {
                            HttpEntity entity = response.getEntity();
                            return entity != null ? EntityUtils.toString(entity, StandardCharsets.UTF_8) : null;
                        } catch (ClientProtocolException e) {
                            return "";
                        }
                    }
                    return "";
                }

            };

            responseBody = httpclient.execute(httpget, responseHandler);
        } finally {
            httpclient.close();
        }

        return responseBody;
    }

}