krysalis-update/src/java/org/krysalis/depot/update/util/net/http HttpClientUserAgent.java,NONE,1.1

Update of /cvsroot/krysalis/krysalis-update/src/java/org/krysalis/depot/update/util/net/http
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv24726/src/java/org/krysalis/depot/update/util/net/http

Added Files:
	HttpClientUserAgent.java 
Log Message:
Copied from the apache incubator.

--- NEW FILE: HttpClientUserAgent.java ---
/*
 * Copyright  2004 The Apache 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.krysalis.depot.update.util.net.http;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.MultiThreadedHttpConnectionManager;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.HeadMethod;
import org.apache.commons.httpclient.util.HttpURLConnection;
import org.krysalis.depot.common.log.Logger;
import org.krysalis.depot.common.util.SystemUtils;
import org.krysalis.depot.common.util.io.IOUtils;

/**
 * @author arb_jack
 * 
 * A simple UserAgent
 *  
 */
public class HttpClientUserAgent {
	private HttpClient m_client = null;

	public HttpClientUserAgent() {
		m_client = new HttpClient(new MultiThreadedHttpConnectionManager());

		//
		// Enable a timeout
		//
		// :TODO: Restore when a release has this
		// m_client.getParams().setConnectionManagerTimeout(30000);
	}

	/**
	 * Test if a URL 'exists' by performing an HTTP HEAD and testing the status
	 * code response.
	 * 
	 * @param url
	 * @return
	 */
	public boolean exists(String url) throws Exception {
		boolean exists = false;

		HeadMethod head = null;

		try {
			head = getHead(url);
			int resultCode = m_client.executeMethod(head);
			exists = (HttpURLConnection.HTTP_OK == resultCode);
		} catch (Exception ex) {
			Logger.getLogger().error("Failed to HTTP HEAD [" + url + "]", ex);
			throw ex;
		} finally {
			if (null != head)
				head.releaseConnection();
		}

		return exists;
	}

	/**
	 * Return the contents of a GET to a URL as a String
	 * 
	 * @param url
	 * @return
	 */
	public String getContents(String url) throws Exception {
		String content = null;

		GetMethod get = null;

		try {
			get = getGet(url);
			int resultCode = m_client.executeMethod(get);
			if (HttpURLConnection.HTTP_OK == resultCode)
				content = get.getResponseBodyAsString();
		} catch (Exception ex) {
			Logger.getLogger().error("Failed to HTTP GET [" + url + "]", ex);
			throw ex;
		} finally {
			if (null != get)
				get.releaseConnection();
		}

		return content;
	}

	/**
	 * Copy the contents of a GET of a URL to another stream
	 * 
	 * @param url
	 * @param output
	 */
	public void transferContents(String url, OutputStream output)
			throws Exception {
		GetMethod get = null;

		try {
			get = getGet(url);

			int resultCode = m_client.executeMethod(get);

			if (HttpURLConnection.HTTP_OK == resultCode) {

				InputStream input = get.getResponseBodyAsStream();
				IOUtils.transfer(input, output);
				IOUtils.close(input);
			}
		} catch (Exception ex) {
			Logger.getLogger().error("Failed to HTTP GET [" + url + "]", ex);

			throw ex;
		} finally {
			if (null != get)
				get.releaseConnection();
		}

	}

	/**
	 * Return a configured HEAD method to a URL
	 * 
	 * @param url
	 * @return
	 */
	private GetMethod getGet(String url) {
		GetMethod get = new GetMethod(url);
		configureMethod(get);
		return get;
	}

	/**
	 * Return a configured HEAD method to a URL
	 * 
	 * @param url
	 * @return
	 */
	private HeadMethod getHead(String url) {
		HeadMethod head = new HeadMethod(url);
		configureMethod(head);
		return head;
	}

	/**
	 * 
	 * Prepares a method with out standard preferences.
	 *  
	 */
	private void configureMethod(HttpMethod method) {

		//
		method.setFollowRedirects(true);

		//
		// Identify use (in case we upset any folks).
		//
		method.setRequestHeader("User-Agent", "Apache-Depot-Update/"
				+ org.apache.acorn.version.version.Version.getInstance().getLongVersion());

	}

	public static void main(String args[]) throws Exception {
		HttpClientUserAgent agent = new HttpClientUserAgent();

		String url = "http://www.ibiblio.org/maven/junit/jars";
		if (args.length > 0)
			url = args[0];

		PrintWriter out = SystemUtils.getSystemOut();

		if (agent.exists(url)) {
			out.println("Exists: " + url);
			out.println("Contents : " + agent.getContents(url));
		}
	}
}


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