/*
 * Copyright 2004 Sun Microsystems, Inc.
 *
 * 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.sun.syndication.fetcher.impl;

import java.net.URLConnection;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Utility class to help deal with HTTP responses
 *
 */
public class ResponseHandler {
	public static final String defaultCharacterEncoding = "ISO-8859-1";
	
	private final static Pattern characterEncodingPattern = Pattern.compile("charset=([.[^; ]]*)");
	
	public static String getCharacterEncoding(URLConnection connection) {
		return getCharacterEncoding(connection.getContentType());
	}
	
	/**
	 * 
	 * <p>Gets the character encoding of a response. (Note that this is different to
	 * the content-encoding)</p>
	 * 
	 * @param contentTypeHeader the value of the content-type HTTP header eg: text/html; charset=ISO-8859-4
	 * @return the character encoding, eg: ISO-8859-4
	 */
	public static String getCharacterEncoding(String contentTypeHeader) {
		if (contentTypeHeader == null) {
			return defaultCharacterEncoding;
		}
		
		Matcher m = characterEncodingPattern.matcher(contentTypeHeader);
		//if (!m.matches()) {
		if (!m.find()) {
			return defaultCharacterEncoding;
		} else {
			return m.group(1);
		}
	}
}
