au.org.ala.bhl.service.WebServiceHelper.java Source code

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Here is the source code for au.org.ala.bhl.service.WebServiceHelper.java

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/*******************************************************************************
 * Copyright (C) 2011 Atlas of Living Australia
 * All Rights Reserved.
 *   
 * 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.
 ******************************************************************************/
package au.org.ala.bhl.service;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.codehaus.jackson.JsonNode;
import org.codehaus.jackson.map.ObjectMapper;

/**
 * Utility class for extracting data from web service (i.e. http GET) calls
 * @author baird
 *
 */
public class WebServiceHelper {

    /**
     * Performs a GET on the specified URI, and expects that the output is well formed JSON. The output is parsed into a JsonNode for consumption
     * 
     * @param uri
     * @return
     * @throws IOException
     */
    public static JsonNode getJSON(String uri) throws IOException {
        HttpClient httpclient = new DefaultHttpClient();
        HttpGet httpget = new HttpGet(uri);
        httpget.setHeader("Accept", "application/json");
        HttpResponse response = httpclient.execute(httpget);
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            InputStream instream = entity.getContent();
            @SuppressWarnings("unchecked")
            List<String> lines = IOUtils.readLines(instream, "utf-8");
            String text = StringUtils.join(lines, "\n");
            try {
                JsonNode root = new ObjectMapper().readValue(text, JsonNode.class);
                return root;
            } catch (Exception ex) {
                log("Error parsing results for request: %s\n%s\n", uri, text);
                ex.printStackTrace();
            }

        }
        return null;
    }

    /**
     * Log a message
     */
    private static void log(String format, Object... args) {
        LogService.log(WebServiceHelper.class, format, args);
    }

    /**
     * Performs a GET on the specified URI, and returns the body without any transformation
     * 
     * @param uri
     * @return
     * @throws IOException
     */
    public static String getText(String uri) throws IOException {
        HttpClient httpclient = new DefaultHttpClient();
        HttpGet httpget = new HttpGet(uri);
        httpget.setHeader("Accept", "application/text");
        HttpResponse response = httpclient.execute(httpget);
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            InputStream instream = entity.getContent();
            @SuppressWarnings("unchecked")
            List<String> lines = IOUtils.readLines(instream, "utf-8");
            return StringUtils.join(lines, "\n");
        }
        return null;
    }

}