KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > commons > httpclient > HttpParser


1 /*
2  * $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/HttpParser.java,v 1.7.2.1 2004/02/22 18:21:13 olegk Exp $
3  * $Revision: 1.7.2.1 $
4  * $Date: 2004/02/22 18:21:13 $
5  *
6  * ====================================================================
7  *
8  * Copyright 1999-2004 The Apache Software Foundation
9  *
10  * Licensed under the Apache License, Version 2.0 (the "License");
11  * you may not use this file except in compliance with the License.
12  * You may obtain a copy of the License at
13  *
14  * http://www.apache.org/licenses/LICENSE-2.0
15  *
16  * Unless required by applicable law or agreed to in writing, software
17  * distributed under the License is distributed on an "AS IS" BASIS,
18  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19  * See the License for the specific language governing permissions and
20  * limitations under the License.
21  * ====================================================================
22  *
23  * This software consists of voluntary contributions made by many
24  * individuals on behalf of the Apache Software Foundation. For more
25  * information on the Apache Software Foundation, please see
26  * <http://www.apache.org/>.
27  *
28  * [Additional notices, if required by prior licensing conditions]
29  *
30  */
31
32 package org.apache.commons.httpclient;
33
34 import java.io.IOException JavaDoc;
35 import java.io.InputStream JavaDoc;
36 import java.io.ByteArrayOutputStream JavaDoc;
37 import java.util.ArrayList JavaDoc;
38
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.
44  *
45  * @author Michael Becke
46  * @author <a HREF="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
47  *
48  * @since 2.0beta1
49  */
50 public class HttpParser {
51
52     /** Log object for this class. */
53     private static final Log LOG = LogFactory.getLog(HttpParser.class);
54     
55     /**
56      * Constructor for HttpParser.
57      */
58     private HttpParser() { }
59
60     /**
61      * Return byte array from an (unchunked) input stream.
62      * Stop reading when <tt>"\n"</tt> terminator encountered
63      * If the stream ends before the line terminator is found,
64      * the last part of the string will still be returned.
65      * If no input data available, <code>null</code> is returned
66      *
67      * @param inputStream the stream to read from
68      *
69      * @throws IOException if an I/O problem occurs
70      * @return a byte array from the stream
71      */
72     public static byte[] readRawLine(InputStream JavaDoc inputStream) throws IOException JavaDoc {
73         LOG.trace("enter HttpParser.readRawLine()");
74
75         ByteArrayOutputStream JavaDoc buf = new ByteArrayOutputStream JavaDoc();
76         int ch;
77         while ((ch = inputStream.read()) >= 0) {
78             buf.write(ch);
79             if (ch == '\n') {
80                 break;
81             }
82         }
83         if (buf.size() == 0) {
84             return null;
85         }
86         return buf.toByteArray();
87     }
88
89     /**
90      * Read up to <tt>"\n"</tt> from an (unchunked) input stream.
91      * If the stream ends before the line terminator is found,
92      * the last part of the string will still be returned.
93      * If no input data available, <code>null</code> is returned
94      *
95      * @param inputStream the stream to read from
96      *
97      * @throws IOException if an I/O problem occurs
98      * @return a line from the stream
99      */
100
101     public static String JavaDoc readLine(InputStream JavaDoc inputStream) throws IOException JavaDoc {
102         LOG.trace("enter HttpParser.readLine()");
103         byte[] rawdata = readRawLine(inputStream);
104         if (rawdata == null) {
105             return null;
106         }
107         int len = rawdata.length;
108         int offset = 0;
109         if (len > 0) {
110             if (rawdata[len - 1] == '\n') {
111                 offset++;
112                 if (len > 1) {
113                     if (rawdata[len - 2] == '\r') {
114                         offset++;
115                     }
116                 }
117             }
118         }
119         return HttpConstants.getString(rawdata, 0, len - offset);
120     }
121
122     /**
123      * Parses headers from the given stream. Headers with the same name are not
124      * combined.
125      *
126      * @param is the stream to read headers from
127      *
128      * @return an array of headers in the order in which they were parsed
129      *
130      * @throws IOException if an IO error occurs while reading from the stream
131      * @throws HttpException if there is an error parsing a header value
132      */
133     public static Header[] parseHeaders(InputStream JavaDoc is) throws IOException JavaDoc, HttpException {
134         LOG.trace("enter HeaderParser.parseHeaders(HttpConnection, HeaderGroup)");
135
136         ArrayList JavaDoc headers = new ArrayList JavaDoc();
137         String JavaDoc name = null;
138         StringBuffer JavaDoc value = null;
139         for (; ;) {
140             String JavaDoc line = HttpParser.readLine(is);
141             if ((line == null) || (line.length() < 1)) {
142                 break;
143             }
144
145             // Parse the header name and value
146 // Check for folded headers first
147 // Detect LWS-char see HTTP/1.0 or HTTP/1.1 Section 2.2
148 // discussion on folded headers
149 if ((line.charAt(0) == ' ') || (line.charAt(0) == '\t')) {
150                 // we have continuation folded header
151 // so append value
152 if (value != null) {
153                     value.append(' ');
154                     value.append(line.trim());
155                 }
156             } else {
157                 // make sure we save the previous name,value pair if present
158 if (name != null) {
159                     headers.add(new Header(name, value.toString()));
160                 }
161
162                 // Otherwise we should have normal HTTP header line
163 // Parse the header name and value
164 int colon = line.indexOf(":");
165                 if (colon < 0) {
166                     throw new HttpException("Unable to parse header: " + line);
167                 }
168                 name = line.substring(0, colon).trim();
169                 value = new StringBuffer JavaDoc(line.substring(colon + 1).trim());
170             }
171
172         }
173
174         // make sure we save the last name,value pair if present
175 if (name != null) {
176             headers.add(new Header(name, value.toString()));
177         }
178         
179         return (Header[]) headers.toArray(new Header[headers.size()]);
180     }
181     
182 }
183
Popular Tags