/*
* 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.
*/
package org.apache.tomcat.util.http.fileupload;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
/**
* <p> Low level API for processing file uploads.
*
* <p> This class can be used to process data streams conforming to MIME
* 'multipart' format as defined in
* <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>. Arbitrarily
* large amounts of data in the stream can be processed under constant
* memory usage.
*
* <p> The format of the stream is defined in the following way:<br>
*
* <code>
* multipart-body := preamble 1*encapsulation close-delimiter epilogue<br>
* encapsulation := delimiter body CRLF<br>
* delimiter := "--" boundary CRLF<br>
* close-delimiter := "--" boudary "--"<br>
* preamble := <ignore><br>
* epilogue := <ignore><br>
* body := header-part CRLF body-part<br>
* header-part := 1*header CRLF<br>
* header := header-name ":" header-value<br>
* header-name := <printable ascii characters except ":"><br>
* header-value := <any ascii characters except CR & LF><br>
* body-data := <arbitrary data><br>
* </code>
*
* <p>Note that body-data can contain another mulipart entity. There
* is limited support for single pass processing of such nested
* streams. The nested stream is <strong>required</strong> to have a
* boundary token of the same length as the parent stream (see {@link
* #setBoundary(byte[])}).
*
* <p>Here is an exaple of usage of this class.<br>
*
* <pre>
* try {
* MultipartStream multipartStream = new MultipartStream(input,
* boundary);
* boolean nextPart = malitPartStream.skipPreamble();
* OutputStream output;
* while(nextPart) {
* header = chunks.readHeader();
* // process headers
* // create some output stream
* multipartStream.readBodyPart(output);
* nextPart = multipartStream.readBoundary();
* }
* } catch(MultipartStream.MalformedStreamException e) {
* // the stream failed to follow required syntax
* } catch(IOException) {
* // a read or write error occurred
* }
*
* </pre>
*
* @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a>
* @author <a href="mailto:martinc@apache.org">Martin Cooper</a>
* @author Sean C. Sullivan
*
* @version $Id: MultipartStream.java 467222 2006-10-24 03:17:11Z markt $
*/
public class MultipartStream
{
// ----------------------------------------------------- Manifest constants
/**
* The maximum length of <code>header-part</code> that will be
* processed (10 kilobytes = 10240 bytes.).
*/
public static final int HEADER_PART_SIZE_MAX = 10240;
/**
* The default length of the buffer used for processing a request.
*/
protected static final int DEFAULT_BUFSIZE = 4096;
/**
* A byte sequence that marks the end of <code>header-part</code>
* (<code>CRLFCRLF</code>).
*/
protected static final byte[] HEADER_SEPARATOR = {0x0D, 0x0A, 0x0D, 0x0A};
/**
* A byte sequence that that follows a delimiter that will be
* followed by an encapsulation (<code>CRLF</code>).
*/
protected static final byte[] FIELD_SEPARATOR = { 0x0D, 0x0A };
/**
* A byte sequence that that follows a delimiter of the last
* encapsulation in the stream (<code>--</code>).
*/
protected static final byte[] STREAM_TERMINATOR = { 0x2D, 0x2D };
// ----------------------------------------------------------- Data members
/**
* The input stream from which data is read.
*/
private InputStream input;
/**
* The length of the boundary token plus the leading <code>CRLF--</code>.
*/
private int boundaryLength;
/**
* The amount of data, in bytes, that must be kept in the buffer in order
* to detect delimiters reliably.
*/
private int keepRegion;
/**
* The byte sequence that partitions the stream.
*/
private byte[] boundary;
/**
* The length of the buffer used for processing the request.
*/
private int bufSize;
/**
* The buffer used for processing the request.
*/
private byte[] buffer;
/**
* The index of first valid character in the buffer.
* <br>
* 0 <= head < bufSize
*/
private int head;
/**
* The index of last valid characer in the buffer + 1.
* <br>
* 0 <= tail <= bufSize
*/
private int tail;
/**
* The content encoding to use when reading headers.
*/
private String headerEncoding;
// ----------------------------------------------------------- Constructors
/**
* Default constructor.
*
* @see #MultipartStream(InputStream, byte[], int)
* @see #MultipartStream(InputStream, byte[])
*
*/
public MultipartStream()
{
}
/**
* <p> Constructs a <code>MultipartStream</code> with a custom size buffer.
*
* <p> Note that the buffer must be at least big enough to contain the
* boundary string, plus 4 characters for CR/LF and double dash, plus at
* least one byte of data. Too small a buffer size setting will degrade
* performance.
*
* @param input The <code>InputStream</code> to serve as a data source.
* @param boundary The token used for dividing the stream into
* <code>encapsulations</code>.
* @param bufSize The size of the buffer to be used, in bytes.
*
*
* @see #MultipartStream()
* @see #MultipartStream(InputStream, byte[])
*
*/
public MultipartStream(InputStream input,
byte[] boundary,
int bufSize)
{
this.input = input;
this.bufSize = bufSize;
this.buffer = new byte[bufSize];
// We prepend CR/LF to the boundary to chop trailng CR/LF from
// body-data tokens.
this.boundary = new byte[boundary.length + 4];
this.boundaryLength = boundary.length + 4;
this.keepRegion = boundary.length + 3;
this.boundary[0] = 0x0D;
this.boundary[1] = 0x0A;
this.boundary[2] = 0x2D;
this.boundary[3] = 0x2D;
System.arraycopy(boundary, 0, this.boundary, 4, boundary.length);
head = 0;
tail = 0;
}
/**
* <p> Constructs a <code>MultipartStream</code> with a default size buffer.
*
* @param input The <code>InputStream</code> to serve as a data source.
* @param boundary The token used for dividing the stream into
* <code>encapsulations</code>.
*
* @exception IOException when an error occurs.
*
* @see #MultipartStream()
* @see #MultipartStream(InputStream, byte[], int)
*
*/
public MultipartStream(InputStream input,
byte[] boundary)
throws IOException
{
this(input, boundary, DEFAULT_BUFSIZE);
}
// --------------------------------------------------------- Public methods
/**
* Retrieves the character encoding used when reading the headers of an
* individual part. When not specified, or <code>null</code>, the platform
* default encoding is used.
*
* @return The encoding used to read part headers.
*/
public String getHeaderEncoding()
{
return headerEncoding;
}
/**
* Specifies the character encoding to be used when reading the headers of
* individual parts. When not specified, or <code>null</code>, the platform
* default encoding is used.
*
* @param encoding The encoding used to read part headers.
*/
public void setHeaderEncoding(String encoding)
{
headerEncoding = encoding;
}
/**
* Reads a byte from the <code>buffer</code>, and refills it as
* necessary.
*
* @return The next byte from the input stream.
*
* @exception IOException if there is no more data available.
*/
public byte readByte()
throws IOException
{
// Buffer depleted ?
if (head == tail)
{
head = 0;
// Refill.
tail = input.read(buffer, head, bufSize);
if (tail == -1)
{
// No more data available.
throw new IOException("No more data is available");
}
}
return buffer[head++];
}
/**
* Skips a <code>boundary</code> token, and checks whether more
* <code>encapsulations</code> are contained in the stream.
*
* @return <code>true</code> if there are more encapsulations in
* this stream; <code>false</code> otherwise.
*
* @exception MalformedStreamException if the stream ends unexpecetedly or
* fails to follow required syntax.
*/
public boolean readBoundary()
throws MalformedStreamException
{
byte[] marker = new byte[2];
boolean nextChunk = false;
head += boundaryLength;
try
{
marker[0] = readByte();
marker[1] = readByte();
if (arrayequals(marker, STREAM_TERMINATOR, 2))
{
nextChunk = false;
}
else if (arrayequals(marker, FIELD_SEPARATOR, 2))
{
nextChunk = true;
}
else
{
throw new MalformedStreamException(
"Unexpected characters follow a boundary");
}
}
catch (IOException e)
{
throw new MalformedStreamException("Stream ended unexpectedly");
}
return nextChunk;
}
/**
* <p>Changes the boundary token used for partitioning the stream.
*
* <p>This method allows single pass processing of nested multipart
* streams.
*
* <p>The boundary token of the nested stream is <code>required</code>
* to be of the same length as the boundary token in parent stream.
*
* <p>Restoring the parent stream boundary token after processing of a
* nested stream is left to the application.
*
* @param boundary The boundary to be used for parsing of the nested
* stream.
*
* @exception IllegalBoundaryException if the <code>boundary</code>
* has a different length than the one
* being currently parsed.
*/
public void setBoundary(byte[] boundary)
throws IllegalBoundaryException
{
if (boundary.length != boundaryLength - 4)
{
throw new IllegalBoundaryException(
"The length of a boundary token can not be changed");
}
System.arraycopy(boundary, 0, this.boundary, 4, boundary.length);
}
/**
* <p>Reads the <code>header-part</code> of the current
* <code>encapsulation</code>.
*
* <p>Headers are returned verbatim to the input stream, including the
* trailing <code>CRLF</code> marker. Parsing is left to the
* application.
*
* <p><strong>TODO</strong> allow limiting maximum header size to
* protect against abuse.
*
* @return The <code>header-part</code> of the current encapsulation.
*
* @exception MalformedStreamException if the stream ends unexpecetedly.
*/
public String readHeaders()
throws MalformedStreamException
{
int i = 0;
byte b[] = new byte[1];
// to support multi-byte characters
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int sizeMax = HEADER_PART_SIZE_MAX;
int size = 0;
while (i < 4)
{
try
{
b[0] = readByte();
}
catch (IOException e)
{
throw new MalformedStreamException("Stream ended unexpectedly");
}
size++;
if (b[0] == HEADER_SEPARATOR[i])
{
i++;
}
else
{
i = 0;
}
if (size <= sizeMax)
{
baos.write(b[0]);
}
}
String headers = null;
if (headerEncoding != null)
{
try
{
headers = baos.toString(headerEncoding);
}
catch (UnsupportedEncodingException e)
{
// Fall back to platform default if specified encoding is not
// supported.
headers = baos.toString();
}
}
else
{
headers = baos.toString();
}
return headers;
}
/**
* <p>Reads <code>body-data</code> from the current
* <code>encapsulation</code> and writes its contents into the
* output <code>Stream</code>.
*
* <p>Arbitrary large amounts of data can be processed by this
* method using a constant size buffer. (see {@link
* #MultipartStream(InputStream,byte[],int) constructor}).
*
* @param output The <code>Stream</code> to write data into.
*
* @return the amount of data written.
*
* @exception MalformedStreamException if the stream ends unexpectedly.
* @exception IOException if an i/o error occurs.
*/
public int readBodyData(OutputStream output)
throws MalformedStreamException,
IOException
{
boolean done = false;
int pad;
int pos;
int bytesRead;
int total = 0;
while (!done)
{
// Is boundary token present somewere in the buffer?
pos = findSeparator();
if (pos != -1)
{
// Write the rest of the data before the boundary.
output.write(buffer, head, pos - head);
total += pos - head;
head = pos;
done = true;
}
else
{
// Determine how much data should be kept in the
// buffer.
if (tail - head > keepRegion)
{
pad = keepRegion;
}
else
{
pad = tail - head;
}
// Write out the data belonging to the body-data.
output.write(buffer, head, tail - head - pad);
// Move the data to the beging of the buffer.
total += tail - head - pad;
System.arraycopy(buffer, tail - pad, buffer, 0, pad);
// Refill buffer with new data.
head = 0;
bytesRead = input.read(buffer, pad, bufSize - pad);
// [pprrrrrrr]
if (bytesRead != -1)
{
tail = pad + bytesRead;
}
else
{
// The last pad amount is left in the buffer.
// Boundary can't be in there so write out the
// data you have and signal an error condition.
output.write(buffer, 0, pad);
output.flush();
total += pad;
throw new MalformedStreamException(
"Stream ended unexpectedly");
}
}
}
output.flush();
return total;
}
/**
* <p> Reads <code>body-data</code> from the current
* <code>encapsulation</code> and discards it.
*
* <p>Use this method to skip encapsulations you don't need or don't
* understand.
*
* @return The amount of data discarded.
*
* @exception MalformedStreamException if the stream ends unexpectedly.
* @exception IOException if an i/o error occurs.
*/
public int discardBodyData()
throws MalformedStreamException,
IOException
{
boolean done = false;
int pad;
int pos;
int bytesRead;
int total = 0;
while (!done)
{
// Is boundary token present somewere in the buffer?
pos = findSeparator();
if (pos != -1)
{
// Write the rest of the data before the boundary.
total += pos - head;
head = pos;
done = true;
}
else
{
// Determine how much data should be kept in the
// buffer.
if (tail - head > keepRegion)
{
pad = keepRegion;
}
else
{
pad = tail - head;
}
total += tail - head - pad;
// Move the data to the beging of the buffer.
System.arraycopy(buffer, tail - pad, buffer, 0, pad);
// Refill buffer with new data.
head = 0;
bytesRead = input.read(buffer, pad, bufSize - pad);
// [pprrrrrrr]
if (bytesRead != -1)
{
tail = pad + bytesRead;
}
else
{
// The last pad amount is left in the buffer.
// Boundary can't be in there so signal an error
// condition.
total += pad;
throw new MalformedStreamException(
"Stream ended unexpectedly");
}
}
}
return total;
}
/**
* Finds the beginning of the first <code>encapsulation</code>.
*
* @return <code>true</code> if an <code>encapsulation</code> was found in
* the stream.
*
* @exception IOException if an i/o error occurs.
*/
public boolean skipPreamble()
throws IOException
{
// First delimiter may be not preceeded with a CRLF.
System.arraycopy(boundary, 2, boundary, 0, boundary.length - 2);
boundaryLength = boundary.length - 2;
try
{
// Discard all data up to the delimiter.
discardBodyData();
// Read boundary - if succeded, the stream contains an
// encapsulation.
return readBoundary();
}
catch (MalformedStreamException e)
{
return false;
}
finally
{
// Restore delimiter.
System.arraycopy(boundary, 0, boundary, 2, boundary.length - 2);
boundaryLength = boundary.length;
boundary[0] = 0x0D;
boundary[1] = 0x0A;
}
}
/**
* Compares <code>count</code> first bytes in the arrays
* <code>a</code> and <code>b</code>.
*
* @param a The first array to compare.
* @param b The second array to compare.
* @param count How many bytes should be compared.
*
* @return <code>true</code> if <code>count</code> first bytes in arrays
* <code>a</code> and <code>b</code> are equal.
*/
public static boolean arrayequals(byte[] a,
byte[] b,
int count)
{
for (int i = 0; i < count; i++)
{
if (a[i] != b[i])
{
return false;
}
}
return true;
}
/**
* Searches for a byte of specified value in the <code>buffer</code>,
* starting at the specified <code>position</code>.
*
* @param value The value to find.
* @param pos The starting position for searching.
*
* @return The position of byte found, counting from beginning of the
* <code>buffer</code>, or <code>-1</code> if not found.
*/
protected int findByte(byte value,
int pos)
{
for (int i = pos; i < tail; i++)
{
if (buffer[i] == value)
{
return i;
}
}
return -1;
}
/**
* Searches for the <code>boundary</code> in the <code>buffer</code>
* region delimited by <code>head</code> and <code>tail</code>.
*
* @return The position of the boundary found, counting from the
* beginning of the <code>buffer</code>, or <code>-1</code> if
* not found.
*/
protected int findSeparator()
{
int first;
int match = 0;
int maxpos = tail - boundaryLength;
for (first = head;
(first <= maxpos) && (match != boundaryLength);
first++)
{
first = findByte(boundary[0], first);
if (first == -1 || (first > maxpos))
{
return -1;
}
for (match = 1; match < boundaryLength; match++)
{
if (buffer[first + match] != boundary[match])
{
break;
}
}
}
if (match == boundaryLength)
{
return first - 1;
}
return -1;
}
/**
* Returns a string representation of this object.
*
* @return The string representation of this object.
*/
public String toString()
{
StringBuffer sbTemp = new StringBuffer();
sbTemp.append("boundary='");
sbTemp.append(String.valueOf(boundary));
sbTemp.append("'\nbufSize=");
sbTemp.append(bufSize);
return sbTemp.toString();
}
/**
* Thrown to indicate that the input stream fails to follow the
* required syntax.
*/
public class MalformedStreamException
extends IOException
{
/**
* Constructs a <code>MalformedStreamException</code> with no
* detail message.
*/
public MalformedStreamException()
{
super();
}
/**
* Constructs an <code>MalformedStreamException</code> with
* the specified detail message.
*
* @param message The detail message.
*/
public MalformedStreamException(String message)
{
super(message);
}
}
/**
* Thrown upon attempt of setting an invalid boundary token.
*/
public class IllegalBoundaryException
extends IOException
{
/**
* Constructs an <code>IllegalBoundaryException</code> with no
* detail message.
*/
public IllegalBoundaryException()
{
super();
}
/**
* Constructs an <code>IllegalBoundaryException</code> with
* the specified detail message.
*
* @param message The detail message.
*/
public IllegalBoundaryException(String message)
{
super(message);
}
}
// ------------------------------------------------------ Debugging methods
// These are the methods that were used to debug this stuff.
/*
// Dump data.
protected void dump()
{
System.out.println("01234567890");
byte[] temp = new byte[buffer.length];
for(int i=0; i<buffer.length; i++)
{
if (buffer[i] == 0x0D || buffer[i] == 0x0A)
{
temp[i] = 0x21;
}
else
{
temp[i] = buffer[i];
}
}
System.out.println(new String(temp));
int i;
for (i=0; i<head; i++)
System.out.print(" ");
System.out.println("h");
for (i=0; i<tail; i++)
System.out.print(" ");
System.out.println("t");
System.out.flush();
}
// Main routine, for testing purposes only.
//
// @param args A String[] with the command line arguments.
// @exception Exception, a generic exception.
public static void main( String[] args )
throws Exception
{
File boundaryFile = new File("boundary.dat");
int boundarySize = (int)boundaryFile.length();
byte[] boundary = new byte[boundarySize];
FileInputStream input = new FileInputStream(boundaryFile);
input.read(boundary,0,boundarySize);
input = new FileInputStream("multipart.dat");
MultipartStream chunks = new MultipartStream(input, boundary);
int i = 0;
String header;
OutputStream output;
boolean nextChunk = chunks.skipPreamble();
while (nextChunk)
{
header = chunks.readHeaders();
System.out.println("!"+header+"!");
System.out.println("wrote part"+i+".dat");
output = new FileOutputStream("part"+(i++)+".dat");
chunks.readBodyData(output);
nextChunk = chunks.readBoundary();
}
}
*/
}
|
