View Javadoc

    1   /*
    2    * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/ChunkedInputStream.java,v 1.24 2004/10/10 15:18:55 olegk Exp $
    3    * $Revision: 480424 $
    4    * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
    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.ByteArrayOutputStream;
    34  import java.io.IOException;
    35  import java.io.InputStream;
    36
    37  import org.apache.commons.httpclient.util.EncodingUtil;
    38  import org.apache.commons.httpclient.util.ExceptionUtil;
    39  import org.apache.commons.logging.Log;
    40  import org.apache.commons.logging.LogFactory;
    41
    42
    43  /**
    44   * <p>Transparently coalesces chunks of a HTTP stream that uses
    45   * Transfer-Encoding chunked.</p>
    46   *
    47   * <p>Note that this class NEVER closes the underlying stream, even when close
    48   * gets called.  Instead, it will read until the "end" of its chunking on close,
    49   * which allows for the seamless invocation of subsequent HTTP 1.1 calls, while
    50   * not requiring the client to remember to read the entire contents of the
    51   * response.</p>
    52   *
    53   * @author Ortwin Glueck
    54   * @author Sean C. Sullivan
    55   * @author Martin Elwin
    56   * @author Eric Johnson
    57   * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
    58   * @author Michael Becke
    59   * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
    60   *
    61   * @since 2.0
    62   *
    63   */
    64  public class ChunkedInputStream extends InputStream {
    65      /** The inputstream that we're wrapping */
    66      private InputStream in;
    67
    68      /** The chunk size */
    69      private int chunkSize;
    70
    71      /** The current position within the current chunk */
    72      private int pos;
    73
    74      /** True if we'are at the beginning of stream */
    75      private boolean bof = true;
    76
    77      /** True if we've reached the end of stream */
    78      private boolean eof = false;
    79
    80      /** True if this stream is closed */
    81      private boolean closed = false;
    82
    83      /** The method that this stream came from */
    84      private HttpMethod method = null;
    85
    86      /** Log object for this class. */
    87      private static final Log LOG = LogFactory.getLog(ChunkedInputStream.class);
    88
    89      /**
    90       * ChunkedInputStream constructor that associates the chunked input stream with a
    91       * {@link HttpMethod HTTP method}. Usually it should be the same {@link HttpMethod
    92       * HTTP method} the chunked input stream originates from. If chunked input stream
    93       * contains any footers (trailing headers), they will be added to the associated
    94       * {@link HttpMethod HTTP method}.
    95       *
    96       * @param in the raw input stream
    97       * @param method the HTTP method to associate this input stream with. Can be <tt>null</tt>.
    98       *
    99       * @throws IOException If an IO error occurs
    100      */
    101     public ChunkedInputStream(
    102         final InputStream in, final HttpMethod method) throws IOException {
    103
    104     	if (in == null) {
    105     		throw new IllegalArgumentException("InputStream parameter may not be null");
    106     	}
    107         this.in = in;
    108         this.method = method;
    109         this.pos = 0;
    110     }
    111
    112     /**
    113      * ChunkedInputStream constructor
    114      *
    115      * @param in the raw input stream
    116      *
    117      * @throws IOException If an IO error occurs
    118      */
    119     public ChunkedInputStream(final InputStream in) throws IOException {
    120     	this(in, null);
    121     }
    122
    123     /**
    124      * <p> Returns all the data in a chunked stream in coalesced form. A chunk
    125      * is followed by a CRLF. The method returns -1 as soon as a chunksize of 0
    126      * is detected.</p>
    127      *
    128      * <p> Trailer headers are read automcatically at the end of the stream and
    129      * can be obtained with the getResponseFooters() method.</p>
    130      *
    131      * @return -1 of the end of the stream has been reached or the next data
    132      * byte
    133      * @throws IOException If an IO problem occurs
    134      *
    135      * @see HttpMethod#getResponseFooters()
    136      */
    137     public int read() throws IOException {
    138
    139         if (closed) {
    140             throw new IOException("Attempted read from closed stream.");
    141         }
    142         if (eof) {
    143             return -1;
    144         }
    145         if (pos >= chunkSize) {
    146             nextChunk();
    147             if (eof) {
    148                 return -1;
    149             }
    150         }
    151         pos++;
    152         return in.read();
    153     }
    154
    155     /**
    156      * Read some bytes from the stream.
    157      * @param b The byte array that will hold the contents from the stream.
    158      * @param off The offset into the byte array at which bytes will start to be
    159      * placed.
    160      * @param len the maximum number of bytes that can be returned.
    161      * @return The number of bytes returned or -1 if the end of stream has been
    162      * reached.
    163      * @see java.io.InputStream#read(byte[], int, int)
    164      * @throws IOException if an IO problem occurs.
    165      */
    166     public int read (byte[] b, int off, int len) throws IOException {
    167
    168         if (closed) {
    169             throw new IOException("Attempted read from closed stream.");
    170         }
    171
    172         if (eof) {
    173             return -1;
    174         }
    175         if (pos >= chunkSize) {
    176             nextChunk();
    177             if (eof) {
    178                 return -1;
    179             }
    180         }
    181         len = Math.min(len, chunkSize - pos);
    182         int count = in.read(b, off, len);
    183         pos += count;
    184         return count;
    185     }
    186
    187     /**
    188      * Read some bytes from the stream.
    189      * @param b The byte array that will hold the contents from the stream.
    190      * @return The number of bytes returned or -1 if the end of stream has been
    191      * reached.
    192      * @see java.io.InputStream#read(byte[])
    193      * @throws IOException if an IO problem occurs.
    194      */
    195     public int read (byte[] b) throws IOException {
    196         return read(b, 0, b.length);
    197     }
    198
    199     /**
    200      * Read the CRLF terminator.
    201      * @throws IOException If an IO error occurs.
    202      */
    203     private void readCRLF() throws IOException {
    204         int cr = in.read();
    205         int lf = in.read();
    206         if ((cr != '\r') || (lf != '\n')) {
    207             throw new IOException(
    208                 "CRLF expected at end of chunk: " + cr + "/" + lf);
    209         }
    210     }
    211
    212
    213     /**
    214      * Read the next chunk.
    215      * @throws IOException If an IO error occurs.
    216      */
    217     private void nextChunk() throws IOException {
    218         if (!bof) {
    219             readCRLF();
    220         }
    221         chunkSize = getChunkSizeFromInputStream(in);
    222         bof = false;
    223         pos = 0;
    224         if (chunkSize == 0) {
    225             eof = true;
    226             parseTrailerHeaders();
    227         }
    228     }
    229
    230     /**
    231      * Expects the stream to start with a chunksize in hex with optional
    232      * comments after a semicolon. The line must end with a CRLF: "a3; some
    233      * comment\r\n" Positions the stream at the start of the next line.
    234      *
    235      * @param in The new input stream.
    236      * @param required <tt>true<tt/> if a valid chunk must be present,
    237      *                 <tt>false<tt/> otherwise.
    238      *
    239      * @return the chunk size as integer
    240      *
    241      * @throws IOException when the chunk size could not be parsed
    242      */
    243     private static int getChunkSizeFromInputStream(final InputStream in)
    244       throws IOException {
    245
    246         ByteArrayOutputStream baos = new ByteArrayOutputStream();
    247         // States: 0=normal, 1=\r was scanned, 2=inside quoted string, -1=end
    248         int state = 0;
    249         while (state != -1) {
    250         int b = in.read();
    251             if (b == -1) {
    252                 throw new IOException("chunked stream ended unexpectedly");
    253             }
    254             switch (state) {
    255                 case 0:
    256                     switch (b) {
    257                         case '\r':
    258                             state = 1;
    259                             break;
    260                         case '\"':
    261                             state = 2;
    262                             /* fall through */
    263                         default:
    264                             baos.write(b);
    265                     }
    266                     break;
    267
    268                 case 1:
    269                     if (b == '\n') {
    270                         state = -1;
    271                     } else {
    272                         // this was not CRLF
    273                         throw new IOException("Protocol violation: Unexpected"
    274                             + " single newline character in chunk size");
    275                     }
    276                     break;
    277
    278                 case 2:
    279                     switch (b) {
    280                         case '\\':
    281                             b = in.read();
    282                             baos.write(b);
    283                             break;
    284                         case '\"':
    285                             state = 0;
    286                             /* fall through */
    287                         default:
    288                             baos.write(b);
    289                     }
    290                     break;
    291                 default: throw new RuntimeException("assertion failed");
    292             }
    293         }
    294
    295         //parse data
    296         String dataString = EncodingUtil.getAsciiString(baos.toByteArray());
    297         int separator = dataString.indexOf(';');
    298         dataString = (separator > 0)
    299             ? dataString.substring(0, separator).trim()
    300             : dataString.trim();
    301
    302         int result;
    303         try {
    304             result = Integer.parseInt(dataString.trim(), 16);
    305         } catch (NumberFormatException e) {
    306             throw new IOException ("Bad chunk size: " + dataString);
    307         }
    308         return result;
    309     }
    310
    311     /**
    312      * Reads and stores the Trailer headers.
    313      * @throws IOException If an IO problem occurs
    314      */
    315     private void parseTrailerHeaders() throws IOException {
    316         Header[] footers = null;
    317         try {
    318             String charset = "US-ASCII";
    319             if (this.method != null) {
    320                 charset = this.method.getParams().getHttpElementCharset();
    321             }
    322             footers = HttpParser.parseHeaders(in, charset);
    323         } catch(HttpException e) {
    324             LOG.error("Error parsing trailer headers", e);
    325             IOException ioe = new IOException(e.getMessage());
    326             ExceptionUtil.initCause(ioe, e);
    327             throw ioe;
    328         }
    329         if (this.method != null) {
    330             for (int i = 0; i < footers.length; i++) {
    331                 this.method.addResponseFooter(footers[i]);
    332             }
    333         }
    334     }
    335
    336     /**
    337      * Upon close, this reads the remainder of the chunked message,
    338      * leaving the underlying socket at a position to start reading the
    339      * next response without scanning.
    340      * @throws IOException If an IO problem occurs.
    341      */
    342     public void close() throws IOException {
    343         if (!closed) {
    344             try {
    345                 if (!eof) {
    346                     exhaustInputStream(this);
    347                 }
    348             } finally {
    349                 eof = true;
    350                 closed = true;
    351             }
    352         }
    353     }
    354
    355     /**
    356      * Exhaust an input stream, reading until EOF has been encountered.
    357      *
    358      * <p>Note that this function is intended as a non-public utility.
    359      * This is a little weird, but it seemed silly to make a utility
    360      * class for this one function, so instead it is just static and
    361      * shared that way.</p>
    362      *
    363      * @param inStream The {@link InputStream} to exhaust.
    364      * @throws IOException If an IO problem occurs
    365      */
    366     static void exhaustInputStream(InputStream inStream) throws IOException {
    367         // read and discard the remainder of the message
    368         byte buffer[] = new byte[1024];
    369         while (inStream.read(buffer) >= 0) {
    370             ;
    371         }
    372     }
    373 }