Java tutorial
/* * Digital Audio Access Protocol (DAAP) Library * Copyright (C) 2004-2010 Roger Kapsi * * 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.ardverk.daap.bio; /* * $HeadURL$ * $Revision$ * $Date$ * * ==================================================================== * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.ProtocolException; import java.util.ArrayList; import java.util.List; import org.apache.http.Header; import org.apache.http.HttpException; import org.apache.http.message.BasicHeader; import org.apache.http.util.EncodingUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * A utility class for parsing http header values according to RFC-2616 Section * 4 and 19.3. * * @author Michael Becke * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a> * * @since 2.0beta1 */ public class HttpParser { /** Log object for this class. */ private static final Logger LOG = LoggerFactory.getLogger(HttpParser.class); /** * Constructor for HttpParser. */ private HttpParser() { } /** * Return byte array from an (unchunked) input stream. Stop reading when * <tt>"\n"</tt> terminator encountered If the stream ends before the line * terminator is found, the last part of the string will still be returned. * If no input data available, <code>null</code> is returned. * * @param inputStream * the stream to read from * * @throws IOException * if an I/O problem occurs * @return a byte array from the stream */ public static byte[] readRawLine(InputStream inputStream) throws IOException { LOG.trace("enter HttpParser.readRawLine()"); ByteArrayOutputStream buf = new ByteArrayOutputStream(); int ch; while ((ch = inputStream.read()) >= 0) { buf.write(ch); if (ch == '\n') { // be tolerant (RFC-2616 Section 19.3) break; } } if (buf.size() == 0) { return null; } return buf.toByteArray(); } /** * Read up to <tt>"\n"</tt> from an (unchunked) input stream. If the stream * ends before the line terminator is found, the last part of the string * will still be returned. If no input data available, <code>null</code> is * returned. * * @param inputStream * the stream to read from * @param charset * charset of HTTP protocol elements * * @throws IOException * if an I/O problem occurs * @return a line from the stream * * @since 3.0 */ public static String readLine(InputStream inputStream, String charset) throws IOException { LOG.trace("enter HttpParser.readLine(InputStream, String)"); byte[] rawdata = readRawLine(inputStream); if (rawdata == null) { return null; } // strip CR and LF from the end int len = rawdata.length; int offset = 0; if (len > 0) { if (rawdata[len - 1] == '\n') { offset++; if (len > 1) { if (rawdata[len - 2] == '\r') { offset++; } } } } final String result = EncodingUtils.getString(rawdata, 0, len - offset, charset); return result; } /** * Read up to <tt>"\n"</tt> from an (unchunked) input stream. If the stream * ends before the line terminator is found, the last part of the string * will still be returned. If no input data available, <code>null</code> is * returned * * @param inputStream * the stream to read from * * @throws IOException * if an I/O problem occurs * @return a line from the stream * * @deprecated use #readLine(InputStream, String) */ public static String readLine(InputStream inputStream) throws IOException { LOG.trace("enter HttpParser.readLine(InputStream)"); return readLine(inputStream, "US-ASCII"); } /** * Parses headers from the given stream. Headers with the same name are not * combined. * * @param is * the stream to read headers from * @param charset * the charset to use for reading the data * * @return an array of headers in the order in which they were parsed * * @throws IOException * if an IO error occurs while reading from the stream * @throws HttpException * if there is an error parsing a header value * * @since 3.0 */ public static Header[] parseHeaders(InputStream is, String charset) throws IOException, HttpException { LOG.trace("enter HeaderParser.parseHeaders(InputStream, String)"); List<Header> headers = new ArrayList<Header>(); String name = null; StringBuffer value = null; for (;;) { String line = HttpParser.readLine(is, charset); if ((line == null) || (line.trim().length() < 1)) { break; } // Parse the header name and value // Check for folded headers first // Detect LWS-char see HTTP/1.0 or HTTP/1.1 Section 2.2 // discussion on folded headers if ((line.charAt(0) == ' ') || (line.charAt(0) == '\t')) { // we have continuation folded header // so append value if (value != null) { value.append(' '); value.append(line.trim()); } } else { // make sure we save the previous name,value pair if present if (name != null) { headers.add(new BasicHeader(name, value.toString())); } // Otherwise we should have normal HTTP header line // Parse the header name and value int colon = line.indexOf(":"); if (colon < 0) { throw new ProtocolException("Unable to parse header: " + line); } name = line.substring(0, colon).trim(); value = new StringBuffer(line.substring(colon + 1).trim()); } } // make sure we save the last name,value pair if present if (name != null) { headers.add(new BasicHeader(name, value.toString())); } return (Header[]) headers.toArray(new Header[headers.size()]); } /** * Parses headers from the given stream. Headers with the same name are not * combined. * * @param is * the stream to read headers from * * @return an array of headers in the order in which they were parsed * * @throws IOException * if an IO error occurs while reading from the stream * @throws HttpException * if there is an error parsing a header value * * @deprecated use #parseHeaders(InputStream, String) */ public static Header[] parseHeaders(InputStream is) throws IOException, HttpException { LOG.trace("enter HeaderParser.parseHeaders(InputStream, String)"); return parseHeaders(is, "US-ASCII"); } }