org.apache.tomcat.util.http.fileupload.MultipartStream Maven / Gradle / Ivy
/*
* 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;
/**
* Low level API for processing file uploads.
*
*
This class can be used to process data streams conforming to MIME
* 'multipart' format as defined in
* RFC 1867. Arbitrarily
* large amounts of data in the stream can be processed under constant
* memory usage.
*
*
The format of the stream is defined in the following way:
*
*
* multipart-body := preamble 1*encapsulation close-delimiter epilogue
* encapsulation := delimiter body CRLF
* delimiter := "--" boundary CRLF
* close-delimiter := "--" boudary "--"
* preamble := <ignore>
* epilogue := <ignore>
* body := header-part CRLF body-part
* header-part := 1*header CRLF
* header := header-name ":" header-value
* header-name := <printable ascii characters except ":">
* header-value := <any ascii characters except CR & LF>
* body-data := <arbitrary data>
*
*
*
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 required to have a
* boundary token of the same length as the parent stream (see {@link
* #setBoundary(byte[])}).
*
*
Here is an exaple of usage of this class.
*
*
* 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
* }
*
*
*
* @author Rafal Krzewski
* @author Martin Cooper
* @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 header-part 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 header-part
* (CRLFCRLF).
*/
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 (CRLF).
*/
protected static final byte[] FIELD_SEPARATOR = { 0x0D, 0x0A };
/**
* A byte sequence that that follows a delimiter of the last
* encapsulation in the stream (--).
*/
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 CRLF--.
*/
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.
*
* 0 <= head < bufSize
*/
private int head;
/**
* The index of last valid characer in the buffer + 1.
*
* 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()
{
}
/**
* Constructs a MultipartStream with a custom size buffer.
*
*
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 InputStream to serve as a data source.
* @param boundary The token used for dividing the stream into
* encapsulations.
* @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;
}
/**
*
Constructs a MultipartStream with a default size buffer.
*
* @param input The InputStream to serve as a data source.
* @param boundary The token used for dividing the stream into
* encapsulations.
*
* @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 null, 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 null, 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 buffer, 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 boundary token, and checks whether more
* encapsulations are contained in the stream.
*
* @return true if there are more encapsulations in
* this stream; false 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;
}
/**
*
Changes the boundary token used for partitioning the stream.
*
*
This method allows single pass processing of nested multipart
* streams.
*
*
The boundary token of the nested stream is required
* to be of the same length as the boundary token in parent stream.
*
*
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 boundary
* 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);
}
/**
*
Reads the header-part of the current
* encapsulation.
*
*
Headers are returned verbatim to the input stream, including the
* trailing CRLF marker. Parsing is left to the
* application.
*
*
TODO allow limiting maximum header size to
* protect against abuse.
*
* @return The header-part 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;
}
/**
*
Reads body-data from the current
* encapsulation and writes its contents into the
* output Stream.
*
*
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 Stream 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;
}
/**
*
Reads body-data from the current
* encapsulation and discards it.
*
*
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 encapsulation.
*
* @return true if an encapsulation 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 count first bytes in the arrays
* a and b.
*
* @param a The first array to compare.
* @param b The second array to compare.
* @param count How many bytes should be compared.
*
* @return true if count first bytes in arrays
* a and b 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 buffer,
* starting at the specified position.
*
* @param value The value to find.
* @param pos The starting position for searching.
*
* @return The position of byte found, counting from beginning of the
* buffer, or -1 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 boundary in the buffer
* region delimited by head and tail.
*
* @return The position of the boundary found, counting from the
* beginning of the buffer, or -1 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 MalformedStreamException with no
* detail message.
*/
public MalformedStreamException()
{
super();
}
/**
* Constructs an MalformedStreamException 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 IllegalBoundaryException with no
* detail message.
*/
public IllegalBoundaryException()
{
super();
}
/**
* Constructs an IllegalBoundaryException 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