eionet.gdem.utils.HttpUtils.java Source code

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Here is the source code for eionet.gdem.utils.HttpUtils.java

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/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is XMLCONV.
 *
 * The Initial Owner of the Original Code is European Environment
 * Agency.  Portions created by Tieto Eesti are Copyright
 * (C) European Environment Agency.  All Rights Reserved.
 *
 * Contributor(s):
 * Enriko Ksper, Tieto Estonia
 */

package eionet.gdem.utils;

import java.io.IOException;
import java.io.InputStream;
import org.apache.commons.io.IOUtils;

import eionet.gdem.dcm.BusinessConstants;
import eionet.gdem.exceptions.DCMException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * HTTP Utilities.
 * TODO: Check if we can replace this with an open source library
 * @author Enriko Ksper, Tieto Estonia HttpUtils
 */

public final class HttpUtils {

    /**
     * Private constructor
     */
    private HttpUtils() {
        // do nothing
    }

    /** */
    private static final Logger LOGGER = LoggerFactory.getLogger(HttpUtils.class);

    /**
     * Downloads remote file
     * @param url URL
     * @return Downloaded file
     * @throws DCMException If an error occurs.
     * @throws IOException If an error occurs.
     */
    public static byte[] downloadRemoteFile(String url) throws DCMException, IOException {
        byte[] responseBody = null;
        CloseableHttpClient client = HttpClients.createDefault();

        // Create a method instance.
        HttpGet method = new HttpGet(url);
        // Execute the method.
        CloseableHttpResponse response = null;
        try {
            response = client.execute(method);
            HttpEntity entity = response.getEntity();
            int statusCode = response.getStatusLine().getStatusCode();

            if (statusCode != HttpStatus.SC_OK) {
                LOGGER.error("Method failed: " + response.getStatusLine().getReasonPhrase());
                throw new DCMException(BusinessConstants.EXCEPTION_SCHEMAOPEN_ERROR,
                        response.getStatusLine().getReasonPhrase());
            }

            // Read the response body.
            InputStream instream = entity.getContent();
            responseBody = IOUtils.toByteArray(instream);

            // Deal with the response.
            // Use caution: ensure correct character encoding and is not binary data
            // System.out.println(new String(responseBody));
            /*catch (HttpException e) {
            LOGGER.error("Fatal protocol violation: " + e.getMessage());
            e.printStackTrace();
            throw e;*/
        } catch (IOException e) {
            LOGGER.error("Fatal transport error: " + e.getMessage());
            e.printStackTrace();
            throw e;
        } finally {
            // Release the connection.
            response.close();
            method.releaseConnection();
            client.close();
        }
        return responseBody;
    }

    /**
     * Method checks whether the resource behind the given URL exist. The method calls HEAD request and if the resonse code is 200,
     * then returns true. If exception is thrown or response code is something else, then the result is false.
     *
     * @param url URL
     * @return True if resource behind the url exists.
     */
    public static boolean urlExists(String url) {

        CloseableHttpClient client = HttpClients.createDefault();

        // Create a method instance.
        HttpHead method = new HttpHead(url);
        CloseableHttpResponse response = null;
        try {
            // Execute the method.
            response = client.execute(method);
            int statusCode = response.getStatusLine().getStatusCode();
            return statusCode == HttpStatus.SC_OK;
            /*} catch (HttpException e) {
                LOGGER.error("Fatal protocol violation: " + e.getMessage());
                e.printStackTrace();
                return false;*/
        } catch (IOException e) {
            LOGGER.error("Fatal transport error: " + e.getMessage());
            e.printStackTrace();
            return false;
        } finally {
            // Release the connection.
            method.releaseConnection();
            try {
                response.close();
            } catch (IOException e) {
                // do nothing
            }
        }
    }
}