HttpClient.java

/*
` *  Copyright 2011 Eric F. Savage, code@efsavage.com
 *
 *   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 com.ajah.util.net;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import com.ajah.util.data.XmlString;
import com.ajah.util.lang.StreamUtils;

/**
 * Simple HTTP client that depends only on JDK libraries. For production-level
 * code, use a more robust solution like the ajah-http library.
 * 
 * @author <a href="http://efsavage.com">Eric F. Savage</a>, <a
 *         href="mailto:code@efsavage.com">code@efsavage.com</a>.
 * 
 */
public class HttpClient {

	/**
	 * Get a byte array version of the target URL.
	 * 
	 * @param url
	 *            The URL to fetch.
	 * @return The results of the URL, if possible, or null.
	 * @throws IOException
	 *             If the file could not be fetched.
	 */
	public static byte[] getBytes(final String url) throws IOException {
		try {
			final URL ur = new URL(url);
			URLConnection conn;
			conn = ur.openConnection();
			return StreamUtils.toByteArray(conn.getInputStream());
		} catch (final MalformedURLException e) {
			return null;
		}
	}

	/**
	 * Get a string version of the target URL.
	 * 
	 * @param url
	 *            The URL to fetch.
	 * @return The results of the URL, if possible, or null.
	 * @throws IOException
	 *             If the file could not be fetched.
	 */
	public static String getString(final String url) throws IOException {
		try {
			final URL ur = new URL(url);
			URLConnection conn;
			conn = ur.openConnection();
			final Object content = conn.getContent();
			if (content instanceof String) {
				return (String) content;
			} else if (InputStream.class.isAssignableFrom(content.getClass())) {
				return new String(StreamUtils.toByteArray((InputStream) content));
			}
			return content.toString();
		} catch (final MalformedURLException e) {
			return null;
		}
	}

	/**
	 * Fetches a URL that is expected to be an XML response.
	 * 
	 * @param url
	 *            The URL to fetch, required.
	 * @return An {@link XmlString} wrapped string version of the response body.
	 * @throws IOException
	 *             If the URL could not be fetched.
	 */
	public static XmlString getXml(final String url) throws IOException {
		return new XmlString(getString(url));
	}

	/**
	 * Get an {@link InputStream} of the target URL.
	 * 
	 * @param url
	 *            The URL to fetch.
	 * @return The results of the URL, if possible, or null.
	 * @throws IOException
	 *             If the file could not be fetched.
	 */
	public static InputStream stream(final String url) throws IOException {
		try {
			final URL ur = new URL(url);
			URLConnection conn;
			conn = ur.openConnection();
			return conn.getInputStream();
		} catch (final MalformedURLException e) {
			return null;
		}
	}

}