/*
* $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/ChunkedInputStream.java,v 1.16.2.2 2004/02/22 18:21:13 olegk Exp $
* $Revision: 1.16.2.2 $
* $Date: 2004/02/22 18:21:13 $
*
* ====================================================================
*
* Copyright 2002-2004 The Apache Software Foundation
*
* 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.
* ====================================================================
*
* 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/>.
*
* [Additional notices, if required by prior licensing conditions]
*
*/
package org.apache.commons.httpclient;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* <p>Transparently coalesces chunks of a HTTP stream that uses
* Transfer-Encoding chunked.</p>
*
* <p>Note that this class NEVER closes the underlying stream, even when close
* gets called. Instead, it will read until the "end" of its chunking on close,
* which allows for the seamless invocation of subsequent HTTP 1.1 calls, while
* not requiring the client to remember to read the entire contents of the
* response.</p>
*
* @see ResponseInputStream
*
* @author Ortwin Gl�ck
* @author Sean C. Sullivan
* @author Martin Elwin
* @author Eric Johnson
* @author <a href="mailto:[email protected]">Mike Bowler</a>
* @author Michael Becke
* @author <a href="mailto:[email protected]">Oleg Kalnichevski</a>
*
* @since 2.0
*
*/
public class ChunkedInputStream extends InputStream {
/** The inputstream that we're wrapping */
private InputStream in;
/** The chunk size */
private int chunkSize;
/** The current position within the current chunk */
private int pos;
/** True if we'are at the beginning of stream */
private boolean bof = true;
/** True if we've reached the end of stream */
private boolean eof = false;
/** True if this stream is closed */
private boolean closed = false;
/** The method that this stream came from */
private HttpMethod method;
/**
*
*
* @param in must be non-null
* @param method must be non-null
*
* @throws IOException If an IO error occurs
*/
public ChunkedInputStream(
final InputStream in, final HttpMethod method) throws IOException {
if (in == null) {
throw new IllegalArgumentException("InputStream parameter may not be null");
}
if (method == null) {
throw new IllegalArgumentException("HttpMethod parameter may not be null");
}
this.in = in;
this.method = method;
this.pos = 0;
}
/**
* <p> Returns all the data in a chunked stream in coalesced form. A chunk
* is followed by a CRLF. The method returns -1 as soon as a chunksize of 0
* is detected.</p>
*
* <p> Trailer headers are read automcatically at the end of the stream and
* can be obtained with the getResponseFooters() method.</p>
*
* @return -1 of the end of the stream has been reached or the next data
* byte
* @throws IOException If an IO problem occurs
*
* @see HttpMethod#getResponseFooters()
*/
public int read() throws IOException {
if (closed) {
throw new IOException("Attempted read from closed stream.");
}
if (eof) {
return -1;
}
if (pos >= chunkSize) {
nextChunk();
if (eof) {
return -1;
}
}
pos++;
return in.read();
}
/**
* Read some bytes from the stream.
* @param b The byte array that will hold the contents from the stream.
* @param off The offset into the byte array at which bytes will start to be
* placed.
* @param len the maximum number of bytes that can be returned.
* @return The number of bytes returned or -1 if the end of stream has been
* reached.
* @see java.io.InputStream#read(byte[], int, int)
* @throws IOException if an IO problem occurs.
*/
public int read (byte[] b, int off, int len) throws IOException {
if (closed) {
throw new IOException("Attempted read from closed stream.");
}
if (eof) {
return -1;
}
if (pos >= chunkSize) {
nextChunk();
if (eof) {
return -1;
}
}
len = Math.min(len, chunkSize - pos);
int count = in.read(b, off, len);
pos += count;
return count;
}
/**
* Read some bytes from the stream.
* @param b The byte array that will hold the contents from the stream.
* @return The number of bytes returned or -1 if the end of stream has been
* reached.
* @see java.io.InputStream#read(byte[])
* @throws IOException if an IO problem occurs.
*/
public int read (byte[] b) throws IOException {
return read(b, 0, b.length);
}
/**
* Read the CRLF terminator.
* @throws IOException If an IO error occurs.
*/
private void readCRLF() throws IOException {
int cr = in.read();
int lf = in.read();
if ((cr != '\r') || (lf != '\n')) {
throw new IOException(
"CRLF expected at end of chunk: " + cr + "/" + lf);
}
}
/**
* Read the next chunk.
* @throws IOException If an IO error occurs.
*/
private void nextChunk() throws IOException {
if (!bof) {
readCRLF();
}
chunkSize = getChunkSizeFromInputStream(in);
bof = false;
pos = 0;
if (chunkSize == 0) {
eof = true;
parseTrailerHeaders();
}
}
/**
* Expects the stream to start with a chunksize in hex with optional
* comments after a semicolon. The line must end with a CRLF: "a3; some
* comment\r\n" Positions the stream at the start of the next line.
*
* @param in The new input stream.
*
* @return the chunk size as integer
*
* @throws IOException when the chunk size could not be parsed
*/
private static int getChunkSizeFromInputStream(final InputStream in)
throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
// States: 0=normal, 1=\r was scanned, 2=inside quoted string, -1=end
int state = 0;
while (state != -1) {
int b = in.read();
if (b == -1) {
throw new IOException("chunked stream ended unexpectedly");
}
switch (state) {
case 0:
switch (b) {
case '\r':
state = 1;
break;
case '\"':
state = 2;
/* fall through */
default:
baos.write(b);
}
break;
case 1:
if (b == '\n') {
state = -1;
} else {
// this was not CRLF
throw new IOException("Protocol violation: Unexpected"
+ " single newline character in chunk size");
}
break;
case 2:
switch (b) {
case '\\':
b = in.read();
baos.write(b);
break;
case '\"':
state = 0;
/* fall through */
default:
baos.write(b);
}
break;
default: throw new RuntimeException("assertion failed");
}
}
//parse data
String dataString = HttpConstants.getString(baos.toByteArray());
int separator = dataString.indexOf(';');
dataString = (separator > 0)
? dataString.substring(0, separator).trim()
: dataString.trim();
int result;
try {
result = Integer.parseInt(dataString.trim(), 16);
} catch (NumberFormatException e) {
throw new IOException ("Bad chunk size: " + dataString);
}
return result;
}
/**
* Reads and stores the Trailer headers.
* @throws IOException If an IO problem occurs
*/
private void parseTrailerHeaders() throws IOException {
Header[] footers = HttpParser.parseHeaders(in);
for (int i = 0; i < footers.length; i++) {
method.addResponseFooter(footers[i]);
}
}
/**
* Upon close, this reads the remainder of the chunked message,
* leaving the underlying socket at a position to start reading the
* next response without scanning.
* @throws IOException If an IO problem occurs.
*/
public void close() throws IOException {
if (!closed) {
try {
if (!eof) {
exhaustInputStream(this);
}
} finally {
eof = true;
closed = true;
}
}
}
/**
* Exhaust an input stream, reading until EOF has been encountered.
*
* <p>Note that this function is intended as a non-public utility.
* This is a little weird, but it seemed silly to make a utility
* class for this one function, so instead it is just static and
* shared that way.</p>
*
* @param inStream The {@link InputStream} to exhaust.
* @throws IOException If an IO problem occurs
*/
static void exhaustInputStream(InputStream inStream) throws IOException {
// read and discard the remainder of the message
byte buffer[] = new byte[1024];
while (inStream.read(buffer) >= 0) {
;
}
}
}
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