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Commons FileUpload example source code file (MultipartStream.java)

This example Commons FileUpload source code file (MultipartStream.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons FileUpload tags/keywords

cr, dash, illegalboundaryexception, io, ioexception, ioexception, iteminputstream, lf, lf, malformedstreamexception, malformedstreamexception, multipartstream, multipartstream, progressnotifier, string, util

The Commons FileUpload MultipartStream.java source code

/*
 * 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.commons.fileupload;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;

import org.apache.commons.fileupload.util.Closeable;
import org.apache.commons.fileupload.util.Streams;

/**
 * <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. 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:
* * <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 to have a * boundary token of the same length as the parent stream (see {@link * #setBoundary(byte[])}). * * <p>Here is an example of usage of this class.
* * <pre> * try { * MultipartStream multipartStream = new MultipartStream(input, * boundary); * boolean nextPart = multipartStream.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 * @author <a href="mailto:martinc@apache.org">Martin Cooper * @author Sean C. Sullivan * * @version $Id: MultipartStream.java 551000 2007-06-27 00:59:16Z jochen $ */ public class MultipartStream { /** * Internal class, which is used to invoke the * {@link ProgressListener}. */ static class ProgressNotifier { /** The listener to invoke. */ private final ProgressListener listener; /** Number of expected bytes, if known, or -1. */ private final long contentLength; /** Number of bytes, which have been read so far. */ private long bytesRead; /** Number of items, which have been read so far. */ private int items; /** Creates a new instance with the given listener * and content length. * @param pListener The listener to invoke. * @param pContentLength The expected content length. */ ProgressNotifier(ProgressListener pListener, long pContentLength) { listener = pListener; contentLength = pContentLength; } /** Called to indicate that bytes have been read. * @param pBytes Number of bytes, which have been read. */ void noteBytesRead(int pBytes) { /* Indicates, that the given number of bytes have been read from * the input stream. */ bytesRead += pBytes; notifyListener(); } /** Called to indicate, that a new file item has been detected. */ void noteItem() { ++items; } /** Called for notifying the listener. */ private void notifyListener() { if (listener != null) { listener.update(bytesRead, contentLength, items); } } } // ----------------------------------------------------- Manifest constants /** * The Carriage Return ASCII character value. */ public static final byte CR = 0x0D; /** * The Line Feed ASCII character value. */ public static final byte LF = 0x0A; /** * The dash (-) ASCII character value. */ public static final byte DASH = 0x2D; /** * The maximum length of <code>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 <code>header-part * (<code>CRLFCRLF). */ protected static final byte[] HEADER_SEPARATOR = { CR, LF, CR, LF }; /** * A byte sequence that that follows a delimiter that will be * followed by an encapsulation (<code>CRLF). */ protected static final byte[] FIELD_SEPARATOR = { CR, LF}; /** * A byte sequence that that follows a delimiter of the last * encapsulation in the stream (<code>--). */ protected static final byte[] STREAM_TERMINATOR = { DASH, DASH}; /** * A byte sequence that precedes a boundary (<code>CRLF--). */ protected static final byte[] BOUNDARY_PREFIX = { CR, LF, DASH, DASH}; // ----------------------------------------------------------- Data members /** * The input stream from which data is read. */ private final InputStream input; /** * The length of the boundary token plus the leading <code>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 final int bufSize; /** * The buffer used for processing the request. */ private final 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; /** * The progress notifier, if any, or null. */ private final ProgressNotifier notifier; // ----------------------------------------------------------- Constructors /** * Creates a new instance. * @deprecated Use {@link #MultipartStream(InputStream, byte[], * org.apache.commons.fileupload.MultipartStream.ProgressNotifier)}, * or {@link #MultipartStream(InputStream, byte[], int, * org.apache.commons.fileupload.MultipartStream.ProgressNotifier)} */ public MultipartStream() { this(null, null, null); } /** * <p> Constructs a MultipartStream with a custom size buffer * and no progress notifier. * * <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 to serve as a data source. * @param boundary The token used for dividing the stream into * <code>encapsulations. * @param bufSize The size of the buffer to be used, in bytes. * * @see #MultipartStream(InputStream, byte[], ProgressNotifier) * @deprecated Use {@link #MultipartStream(InputStream, byte[], int, * org.apache.commons.fileupload.MultipartStream.ProgressNotifier)}. */ public MultipartStream(InputStream input, byte[] boundary, int bufSize) { this(input, boundary, bufSize, null); } /** * <p> Constructs a MultipartStream 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 to serve as a data source. * @param boundary The token used for dividing the stream into * <code>encapsulations. * @param bufSize The size of the buffer to be used, in bytes. * @param pNotifier The notifier, which is used for calling the * progress listener, if any. * * @see #MultipartStream(InputStream, byte[], ProgressNotifier) */ MultipartStream(InputStream input, byte[] boundary, int bufSize, ProgressNotifier pNotifier) { this.input = input; this.bufSize = bufSize; this.buffer = new byte[bufSize]; this.notifier = pNotifier; // We prepend CR/LF to the boundary to chop trailng CR/LF from // body-data tokens. this.boundary = new byte[boundary.length + BOUNDARY_PREFIX.length]; this.boundaryLength = boundary.length + BOUNDARY_PREFIX.length; this.keepRegion = this.boundary.length; System.arraycopy(BOUNDARY_PREFIX, 0, this.boundary, 0, BOUNDARY_PREFIX.length); System.arraycopy(boundary, 0, this.boundary, BOUNDARY_PREFIX.length, boundary.length); head = 0; tail = 0; } /** * <p> Constructs a MultipartStream with a default size buffer. * * @param input The <code>InputStream to serve as a data source. * @param boundary The token used for dividing the stream into * <code>encapsulations. * @param pNotifier An object for calling the progress listener, if any. * * * @see #MultipartStream(InputStream, byte[], int, ProgressNotifier) */ MultipartStream(InputStream input, byte[] boundary, ProgressNotifier pNotifier) { this(input, boundary, DEFAULT_BUFSIZE, pNotifier); } /** * <p> Constructs a MultipartStream with a default size buffer. * * @param input The <code>InputStream to serve as a data source. * @param boundary The token used for dividing the stream into * <code>encapsulations. * * @deprecated Use {@link #MultipartStream(InputStream, byte[], * ProgressNotifier)}. * @see #MultipartStream(InputStream, byte[], int, ProgressNotifier) */ public MultipartStream(InputStream input, byte[] boundary) { this(input, boundary, DEFAULT_BUFSIZE, null); } // --------------------------------------------------------- Public methods /** * Retrieves the character encoding used when reading the headers of an * individual part. When not specified, or <code>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 <code>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 <code>buffer, and refills it as * necessary. * * @return The next byte from the input stream. * * @throws 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"); } if(notifier != null) { notifier.noteBytesRead(tail); } } return buffer[head++]; } /** * Skips a <code>boundary token, and checks whether more * <code>encapsulations are contained in the stream. * * @return <code>true if there are more encapsulations in * this stream; <code>false otherwise. * * @throws 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(); if (marker[0] == LF) { // Work around IE5 Mac bug with input type=image. // Because the boundary delimiter, not including the trailing // CRLF, must not appear within any file (RFC 2046, section // 5.1.1), we know the missing CR is due to a buggy browser // rather than a file containing something similar to a // boundary. return true; } 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 required * 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. * * @throws IllegalBoundaryException if the <code>boundary * has a different length than the one * being currently parsed. */ public void setBoundary(byte[] boundary) throws IllegalBoundaryException { if (boundary.length != boundaryLength - BOUNDARY_PREFIX.length) { throw new IllegalBoundaryException( "The length of a boundary token can not be changed"); } System.arraycopy(boundary, 0, this.boundary, BOUNDARY_PREFIX.length, boundary.length); } /** * <p>Reads the header-part of the current * <code>encapsulation. * * <p>Headers are returned verbatim to the input stream, including the * trailing <code>CRLF marker. Parsing is left to the * application. * * <p>TODO allow limiting maximum header size to * protect against abuse. * * @return The <code>header-part of the current encapsulation. * * @throws MalformedStreamException if the stream ends unexpecetedly. */ public String readHeaders() throws MalformedStreamException { int i = 0; byte b; // to support multi-byte characters ByteArrayOutputStream baos = new ByteArrayOutputStream(); int size = 0; while (i < HEADER_SEPARATOR.length) { try { b = readByte(); } catch (IOException e) { throw new MalformedStreamException("Stream ended unexpectedly"); } if (++size > HEADER_PART_SIZE_MAX) { throw new MalformedStreamException( "Header section has more than " + HEADER_PART_SIZE_MAX + " bytes (maybe it is not properly terminated)"); } if (b == HEADER_SEPARATOR[i]) { i++; } else { i = 0; } baos.write(b); } 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 body-data from the current * <code>encapsulation and writes its contents into the * output <code>Stream. * * <p>Arbitrary large amounts of data can be processed by this * method using a constant size buffer. (see {@link * #MultipartStream(InputStream,byte[],int, ProgressNotifier) constructor}). * * @param output The <code>Stream to write data into. May * be null, in which case this method is equivalent * to {@link #discardBodyData()}. * * @return the amount of data written. * * @throws MalformedStreamException if the stream ends unexpectedly. * @throws IOException if an i/o error occurs. */ public int readBodyData(OutputStream output) throws MalformedStreamException, IOException { final InputStream istream = newInputStream(); return (int) Streams.copy(istream, output, false); } /** * Creates a new {@link ItemInputStream}. * @return A new instance of {@link ItemInputStream}. */ ItemInputStream newInputStream() { return new ItemInputStream(); } /** * <p> Reads body-data from the current * <code>encapsulation and discards it. * * <p>Use this method to skip encapsulations you don't need or don't * understand. * * @return The amount of data discarded. * * @throws MalformedStreamException if the stream ends unexpectedly. * @throws IOException if an i/o error occurs. */ public int discardBodyData() throws MalformedStreamException, IOException { return readBodyData(null); } /** * Finds the beginning of the first <code>encapsulation. * * @return <code>true if an encapsulation was found in * the stream. * * @throws 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] = CR; boundary[1] = LF; } } /** * Compares <code>count first bytes in the arrays * <code>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 <code>true if count first bytes in arrays * <code>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 <code>buffer, * starting at the specified <code>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 * <code>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 <code>boundary in the buffer * region delimited by <code>head and tail. * * @return The position of the boundary found, counting from the * beginning of the <code>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; } /** * Thrown to indicate that the input stream fails to follow the * required syntax. */ public static class MalformedStreamException extends IOException { /** * Constructs a <code>MalformedStreamException with no * detail message. */ public MalformedStreamException() { super(); } /** * Constructs an <code>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 static class IllegalBoundaryException extends IOException { /** * Constructs an <code>IllegalBoundaryException with no * detail message. */ public IllegalBoundaryException() { super(); } /** * Constructs an <code>IllegalBoundaryException with * the specified detail message. * * @param message The detail message. */ public IllegalBoundaryException(String message) { super(message); } } /** * An {@link InputStream} for reading an items contents. */ public class ItemInputStream extends InputStream implements Closeable { /** The number of bytes, which have been read so far. */ private long total; /** The number of bytes, which must be hold, because * they might be a part of the boundary. */ private int pad; /** The current offset in the buffer. */ private int pos; /** Whether the stream is already closed. */ private boolean closed; /** * Creates a new instance. */ ItemInputStream() { findSeparator(); } /** * Called for finding the separator. */ private void findSeparator() { pos = MultipartStream.this.findSeparator(); if (pos == -1) { if (tail - head > keepRegion) { pad = keepRegion; } else { pad = tail - head; } } } /** * Returns the number of bytes, which have been read * by the stream. * @return Number of bytes, which have been read so far. */ public long getBytesRead() { return total; } /** * Returns the number of bytes, which are currently * available, without blocking. * @throws IOException An I/O error occurs. * @return Number of bytes in the buffer. */ public int available() throws IOException { if (pos == -1) { return tail - head - pad; } return pos - head; } /** Offset when converting negative bytes to integers. */ private static final int BYTE_POSITIVE_OFFSET = 256; /** * Returns the next byte in the stream. * @return The next byte in the stream, as a non-negative * integer, or -1 for EOF. * @throws IOException An I/O error occurred. */ public int read() throws IOException { if (closed) { throw new FileItemStream.ItemSkippedException(); } if (available() == 0) { if (makeAvailable() == 0) { return -1; } } ++total; int b = buffer[head++]; if (b >= 0) { return b; } return b + BYTE_POSITIVE_OFFSET; } /** * Reads bytes into the given buffer. * @param b The destination buffer, where to write to. * @param off Offset of the first byte in the buffer. * @param len Maximum number of bytes to read. * @return Number of bytes, which have been actually read, * or -1 for EOF. * @throws IOException An I/O error occurred. */ public int read(byte[] b, int off, int len) throws IOException { if (closed) { throw new FileItemStream.ItemSkippedException(); } if (len == 0) { return 0; } int res = available(); if (res == 0) { res = makeAvailable(); if (res == 0) { return -1; } } res = Math.min(res, len); System.arraycopy(buffer, head, b, off, res); head += res; total += res; return res; } /** * Closes the input stream. * @throws IOException An I/O error occurred. */ public void close() throws IOException { if (closed) { return; } for (;;) { int av = available(); if (av == 0) { av = makeAvailable(); if (av == 0) { break; } } skip(av); } closed = true; } /** * Skips the given number of bytes. * @param bytes Number of bytes to skip. * @return The number of bytes, which have actually been * skipped. * @throws IOException An I/O error occurred. */ public long skip(long bytes) throws IOException { if (closed) { throw new FileItemStream.ItemSkippedException(); } int av = available(); if (av == 0) { av = makeAvailable(); if (av == 0) { return 0; } } long res = Math.min(av, bytes); head += res; return res; } /** * Attempts to read more data. * @return Number of available bytes * @throws IOException An I/O error occurred. */ private int makeAvailable() throws IOException { if (pos != -1) { return 0; } // Move the data to the beginning of the buffer. total += tail - head - pad; System.arraycopy(buffer, tail - pad, buffer, 0, pad); // Refill buffer with new data. head = 0; tail = pad; for(;;) { int bytesRead = input.read(buffer, tail, bufSize - tail); if (bytesRead == -1) { // The last pad amount is left in the buffer. // Boundary can't be in there so signal an error // condition. throw new MalformedStreamException("Stream ended unexpectedly"); } if(notifier != null) { notifier.noteBytesRead(bytesRead); } tail += bytesRead; findSeparator(); int av = available(); if (av > 0 || pos != -1) { return av; } } } /** * Returns, whether the stream is closed. * @return True, if the stream is closed, otherwise false. */ public boolean isClosed() { return closed; } } // ------------------------------------------------------ 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. // @throws 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(); } } */ }

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