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1   /*
2    * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/oac.hc3x/trunk/src/java/org/apache/commons/httpclient/HttpParser.java $
3    * $Revision: 1425331 $
4    * $Date: 2012-12-22 19:29:41 +0100 (Sat, 22 Dec 2012) $
5    *
6    * ====================================================================
7    *
8    *  Licensed to the Apache Software Foundation (ASF) under one or more
9    *  contributor license agreements.  See the NOTICE file distributed with
10   *  this work for additional information regarding copyright ownership.
11   *  The ASF licenses this file to You under the Apache License, Version 2.0
12   *  (the "License"); you may not use this file except in compliance with
13   *  the License.  You may obtain a copy of the License at
14   *
15   *      http://www.apache.org/licenses/LICENSE-2.0
16   *
17   *  Unless required by applicable law or agreed to in writing, software
18   *  distributed under the License is distributed on an "AS IS" BASIS,
19   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20   *  See the License for the specific language governing permissions and
21   *  limitations under the License.
22   * ====================================================================
23   *
24   * This software consists of voluntary contributions made by many
25   * individuals on behalf of the Apache Software Foundation.  For more
26   * information on the Apache Software Foundation, please see
27   * <http://www.apache.org/>.
28   *
29   */
30  
31  package org.apache.commons.httpclient;
32  
33  import java.io.IOException;
34  import java.io.InputStream;
35  import java.io.ByteArrayOutputStream;
36  import java.util.ArrayList;
37  
38  import org.apache.commons.httpclient.util.EncodingUtil;
39  import org.apache.commons.logging.Log;
40  import org.apache.commons.logging.LogFactory;
41  
42  /***
43   * A utility class for parsing http header values according to
44   * RFC-2616 Section 4 and 19.3.
45   * 
46   * @author Michael Becke
47   * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
48   * 
49   * @since 2.0beta1
50   */
51  public class HttpParser {
52  
53      /*** Log object for this class. */
54      private static final Log LOG = LogFactory.getLog(HttpParser.class);
55      
56      /***
57       * Constructor for HttpParser.
58       */
59      private HttpParser() { }
60  
61      /***
62       * Return byte array from an (unchunked) input stream.
63       * Stop reading when <tt>"\n"</tt> terminator encountered 
64       * If the stream ends before the line terminator is found,
65       * the last part of the string will still be returned. 
66       * If no input data available, <code>null</code> is returned.
67       *
68       * @param inputStream the stream to read from
69       *
70       * @throws IOException if an I/O problem occurs
71       * @return a byte array from the stream
72       */
73      public static byte[] readRawLine(InputStream inputStream) throws IOException {
74          LOG.trace("enter HttpParser.readRawLine()");
75  
76          ByteArrayOutputStream buf = new ByteArrayOutputStream();
77          int ch;
78          while ((ch = inputStream.read()) >= 0) {
79              buf.write(ch);
80              if (ch == '\n') { // be tolerant (RFC-2616 Section 19.3)
81                  break;
82              }
83          }
84          if (buf.size() == 0) {
85              return null;
86          }
87          return buf.toByteArray();
88      }
89  
90      /***
91       * Read up to <tt>"\n"</tt> from an (unchunked) input stream.
92       * If the stream ends before the line terminator is found,
93       * the last part of the string will still be returned.
94       * If no input data available, <code>null</code> is returned.
95       *
96       * @param inputStream the stream to read from
97       * @param charset charset of HTTP protocol elements
98       *
99       * @throws IOException if an I/O problem occurs
100      * @return a line from the stream
101      * 
102      * @since 3.0
103      */
104     public static String readLine(InputStream inputStream, String charset) throws IOException {
105         LOG.trace("enter HttpParser.readLine(InputStream, String)");
106         byte[] rawdata = readRawLine(inputStream);
107         if (rawdata == null) {
108             return null;
109         }
110         // strip CR and LF from the end
111         int len = rawdata.length;
112         int offset = 0;
113         if (len > 0) {
114             if (rawdata[len - 1] == '\n') {
115                 offset++;
116                 if (len > 1) {
117                     if (rawdata[len - 2] == '\r') {
118                         offset++;
119                     }
120                 }
121             }
122         }
123         final String result =
124             EncodingUtil.getString(rawdata, 0, len - offset, charset);
125         if (Wire.HEADER_WIRE.enabled()) {
126             String logoutput = result;
127             if (offset == 2)
128                 logoutput = result + "\r\n";
129             else if (offset == 1)
130                 logoutput = result + "\n";
131             Wire.HEADER_WIRE.input(logoutput);
132         }
133         return result;
134     }
135 
136     /***
137      * Read up to <tt>"\n"</tt> from an (unchunked) input stream.
138      * If the stream ends before the line terminator is found,
139      * the last part of the string will still be returned.
140      * If no input data available, <code>null</code> is returned
141      *
142      * @param inputStream the stream to read from
143      *
144      * @throws IOException if an I/O problem occurs
145      * @return a line from the stream
146      * 
147      * @deprecated use #readLine(InputStream, String)
148      */
149 
150     public static String readLine(InputStream inputStream) throws IOException {
151         LOG.trace("enter HttpParser.readLine(InputStream)");
152         return readLine(inputStream, "US-ASCII");
153     }
154     
155     /***
156      * Parses headers from the given stream.  Headers with the same name are not
157      * combined.
158      * 
159      * @param is the stream to read headers from
160      * @param charset the charset to use for reading the data
161      * 
162      * @return an array of headers in the order in which they were parsed
163      * 
164      * @throws IOException if an IO error occurs while reading from the stream
165      * @throws HttpException if there is an error parsing a header value
166      * 
167      * @since 3.0
168      */
169     public static Header[] parseHeaders(InputStream is, String charset) throws IOException, HttpException {
170         LOG.trace("enter HeaderParser.parseHeaders(InputStream, String)");
171 
172         ArrayList headers = new ArrayList();
173         String name = null;
174         StringBuffer value = null;
175         for (; ;) {
176             String line = HttpParser.readLine(is, charset);
177             if ((line == null) || (line.trim().length() < 1)) {
178                 break;
179             }
180 
181             // Parse the header name and value
182             // Check for folded headers first
183             // Detect LWS-char see HTTP/1.0 or HTTP/1.1 Section 2.2
184             // discussion on folded headers
185             if ((line.charAt(0) == ' ') || (line.charAt(0) == '\t')) {
186                 // we have continuation folded header
187                 // so append value
188                 if (value != null) {
189                     value.append(' ');
190                     value.append(line.trim());
191                 }
192             } else {
193                 // make sure we save the previous name,value pair if present
194                 if (name != null) {
195                     headers.add(new Header(name, value.toString()));
196                 }
197 
198                 // Otherwise we should have normal HTTP header line
199                 // Parse the header name and value
200                 int colon = line.indexOf(":");
201                 if (colon < 0) {
202                     throw new ProtocolException("Unable to parse header: " + line);
203                 }
204                 name = line.substring(0, colon).trim();
205                 value = new StringBuffer(line.substring(colon + 1).trim());
206             }
207 
208         }
209 
210         // make sure we save the last name,value pair if present
211         if (name != null) {
212             headers.add(new Header(name, value.toString()));
213         }
214         
215         return (Header[]) headers.toArray(new Header[headers.size()]);    
216     }
217 
218     /***
219      * Parses headers from the given stream.  Headers with the same name are not
220      * combined.
221      * 
222      * @param is the stream to read headers from
223      * 
224      * @return an array of headers in the order in which they were parsed
225      * 
226      * @throws IOException if an IO error occurs while reading from the stream
227      * @throws HttpException if there is an error parsing a header value
228      * 
229      * @deprecated use #parseHeaders(InputStream, String)
230      */
231     public static Header[] parseHeaders(InputStream is) throws IOException, HttpException {
232         LOG.trace("enter HeaderParser.parseHeaders(InputStream, String)");
233         return parseHeaders(is, "US-ASCII");
234     }
235 }