Class MultipartStream
- java.lang.Object
-
- org.apache.commons.fileupload.MultipartStream
-
public class MultipartStream extends java.lang.Object
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 := "--" boundary "--" 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
setBoundary(byte[])
).Here is an example of usage of this class.
try { MultipartStream multipartStream = new MultipartStream(input, boundary); boolean nextPart = multipartStream.skipPreamble(); OutputStream output; while (nextPart) { String header = multipartStream.readHeaders(); // process headers // create some output stream multipartStream.readBodyData(output); nextPart = multipartStream.readBoundary(); } } catch (MultipartStream.MalformedStreamException e) { // the stream failed to follow required syntax } catch (IOException e) { // a read or write error occurred }
-
-
Nested Class Summary
Nested Classes Modifier and Type Class Description static class
MultipartStream.IllegalBoundaryException
Thrown upon attempt of setting an invalid boundary token.class
MultipartStream.ItemInputStream
AnInputStream
for reading an items contents.static class
MultipartStream.MalformedStreamException
Thrown to indicate that the input stream fails to follow the required syntax.static class
MultipartStream.ProgressNotifier
Internal class, which is used to invoke theProgressListener
.
-
Field Summary
Fields Modifier and Type Field Description protected static byte[]
BOUNDARY_PREFIX
A byte sequence that precedes a boundary (CRLF--
).static byte
CR
The Carriage Return ASCII character value.static byte
DASH
The dash (-) ASCII character value.protected static int
DEFAULT_BUFSIZE
The default length of the buffer used for processing a request.protected static byte[]
FIELD_SEPARATOR
A byte sequence that follows a delimiter that will be followed by an encapsulation (CRLF
).static int
HEADER_PART_SIZE_MAX
Deprecated.Unused.protected static byte[]
HEADER_SEPARATOR
A byte sequence that marks the end ofheader-part
(CRLFCRLF
).static byte
LF
The Line Feed ASCII character value.protected static byte[]
STREAM_TERMINATOR
A byte sequence that follows a delimiter of the last encapsulation in the stream (--
).
-
Constructor Summary
Constructors Constructor Description MultipartStream()
Deprecated.MultipartStream(java.io.InputStream input, byte[] boundary)
Deprecated.MultipartStream(java.io.InputStream input, byte[] boundary, int bufSize)
Deprecated.MultipartStream(java.io.InputStream input, byte[] boundary, int bufSize, MultipartStream.ProgressNotifier notifier)
Constructs aMultipartStream
with a custom size buffer.
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static boolean
arrayequals(byte[] a, byte[] b, int count)
Comparescount
first bytes in the arraysa
andb
.int
discardBodyData()
Readsbody-data
from the currentencapsulation
and discards it.protected int
findByte(byte value, int pos)
Searches for a byte of specified value in thebuffer
, starting at the specifiedposition
.protected int
findSeparator()
Searches for theboundary
in thebuffer
region delimited byhead
andtail
.java.lang.String
getHeaderEncoding()
Gets the character encoding used when reading the headers of an individual part.int
getPartHeaderSizeMax()
Obtain the per part size limit for headers.int
readBodyData(java.io.OutputStream output)
Readsbody-data
from the currentencapsulation
and writes its contents into the outputStream
.boolean
readBoundary()
Skips aboundary
token, and checks whether moreencapsulations
are contained in the stream.byte
readByte()
Reads a byte from thebuffer
, and refills it as necessary.java.lang.String
readHeaders()
Reads theheader-part
of the currentencapsulation
.void
setBoundary(byte[] boundary)
Changes the boundary token used for partitioning the stream.void
setHeaderEncoding(java.lang.String encoding)
Specifies the character encoding to be used when reading the headers of individual parts.void
setPartHeaderSizeMax(int partHeaderSizeMax)
Sets the per part size limit for headers.boolean
skipPreamble()
Finds the beginning of the firstencapsulation
.
-
-
-
Field Detail
-
CR
public static final byte CR
The Carriage Return ASCII character value.- See Also:
- Constant Field Values
-
LF
public static final byte LF
The Line Feed ASCII character value.- See Also:
- Constant Field Values
-
DASH
public static final byte DASH
The dash (-) ASCII character value.- See Also:
- Constant Field Values
-
HEADER_PART_SIZE_MAX
@Deprecated public static final int HEADER_PART_SIZE_MAX
Deprecated.Unused. Replaced bygetPartHeaderSizeMax()
.The maximum length ofheader-part
that will be processed (10 kilobytes = 10240 bytes.).- See Also:
- Constant Field Values
-
DEFAULT_BUFSIZE
protected static final int DEFAULT_BUFSIZE
The default length of the buffer used for processing a request.- See Also:
- Constant Field Values
-
HEADER_SEPARATOR
protected static final byte[] HEADER_SEPARATOR
A byte sequence that marks the end ofheader-part
(CRLFCRLF
).
-
FIELD_SEPARATOR
protected static final byte[] FIELD_SEPARATOR
A byte sequence that follows a delimiter that will be followed by an encapsulation (CRLF
).
-
STREAM_TERMINATOR
protected static final byte[] STREAM_TERMINATOR
A byte sequence that follows a delimiter of the last encapsulation in the stream (--
).
-
BOUNDARY_PREFIX
protected static final byte[] BOUNDARY_PREFIX
A byte sequence that precedes a boundary (CRLF--
).
-
-
Constructor Detail
-
MultipartStream
@Deprecated public MultipartStream()
Deprecated.Creates a new instance.
-
MultipartStream
@Deprecated public MultipartStream(java.io.InputStream input, byte[] boundary)
Deprecated.Constructs aMultipartStream
with a default size buffer.- Parameters:
input
- TheInputStream
to serve as a data source.boundary
- The token used for dividing the stream intoencapsulations
.
-
MultipartStream
@Deprecated public MultipartStream(java.io.InputStream input, byte[] boundary, int bufSize)
Deprecated.Constructs aMultipartStream
with a custom size buffer and no progress notifier.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.
- Parameters:
input
- TheInputStream
to serve as a data source.boundary
- The token used for dividing the stream intoencapsulations
.bufSize
- The size of the buffer to be used, in bytes.
-
MultipartStream
public MultipartStream(java.io.InputStream input, byte[] boundary, int bufSize, MultipartStream.ProgressNotifier notifier)
Constructs aMultipartStream
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.
- Parameters:
input
- TheInputStream
to serve as a data source.boundary
- The token used for dividing the stream intoencapsulations
.bufSize
- The size of the buffer to be used, in bytes.notifier
- The notifier, which is used for calling the progress listener, if any.- Throws:
java.lang.IllegalArgumentException
- If the buffer size is too small- Since:
- 1.3.1
-
-
Method Detail
-
arrayequals
public static boolean arrayequals(byte[] a, byte[] b, int count)
Comparescount
first bytes in the arraysa
andb
.- Parameters:
a
- The first array to compare.b
- The second array to compare.count
- How many bytes should be compared.- Returns:
true
ifcount
first bytes in arraysa
andb
are equal.
-
discardBodyData
public int discardBodyData() throws MultipartStream.MalformedStreamException, java.io.IOException
Readsbody-data
from the currentencapsulation
and discards it.Use this method to skip encapsulations you don't need or don't understand.
- Returns:
- The amount of data discarded.
- Throws:
MultipartStream.MalformedStreamException
- if the stream ends unexpectedly.java.io.IOException
- if an i/o error occurs.
-
findByte
protected int findByte(byte value, int pos)
Searches for a byte of specified value in thebuffer
, starting at the specifiedposition
.- Parameters:
value
- The value to find.pos
- The starting position for searching.- Returns:
- The position of byte found, counting from beginning of the
buffer
, or-1
if not found.
-
findSeparator
protected int findSeparator()
Searches for theboundary
in thebuffer
region delimited byhead
andtail
.- Returns:
- The position of the boundary found, counting from the
beginning of the
buffer
, or-1
if not found.
-
getHeaderEncoding
public java.lang.String getHeaderEncoding()
Gets the character encoding used when reading the headers of an individual part. When not specified, ornull
, the platform default encoding is used.- Returns:
- The encoding used to read part headers.
-
getPartHeaderSizeMax
public int getPartHeaderSizeMax()
Obtain the per part size limit for headers.- Returns:
- The maximum size of the headers for a single part in bytes.
- Since:
- 1.6.0
-
readBodyData
public int readBodyData(java.io.OutputStream output) throws MultipartStream.MalformedStreamException, java.io.IOException
Readsbody-data
from the currentencapsulation
and writes its contents into the outputStream
.Arbitrary large amounts of data can be processed by this method using a constant size buffer. (see
constructor
).- Parameters:
output
- TheStream
to write data into. May be null, in which case this method is equivalent todiscardBodyData()
.- Returns:
- the amount of data written.
- Throws:
MultipartStream.MalformedStreamException
- if the stream ends unexpectedly.java.io.IOException
- if an i/o error occurs.
-
readBoundary
public boolean readBoundary() throws FileUploadBase.FileUploadIOException, MultipartStream.MalformedStreamException
Skips aboundary
token, and checks whether moreencapsulations
are contained in the stream.- Returns:
true
if there are more encapsulations in this stream;false
otherwise.- Throws:
FileUploadBase.FileUploadIOException
- if the bytes read from the stream exceeded the size limitsMultipartStream.MalformedStreamException
- if the stream ends unexpectedly or fails to follow required syntax.
-
readByte
public byte readByte() throws java.io.IOException
Reads a byte from thebuffer
, and refills it as necessary.- Returns:
- The next byte from the input stream.
- Throws:
java.io.IOException
- if there is no more data available.
-
readHeaders
public java.lang.String readHeaders() throws FileUploadBase.FileUploadIOException, MultipartStream.MalformedStreamException
Reads theheader-part
of the currentencapsulation
.Headers are returned verbatim to the input stream, including the trailing
CRLF
marker. Parsing is left to the application.- Returns:
- The
header-part
of the current encapsulation. - Throws:
FileUploadBase.FileUploadIOException
- if the bytes read from the stream exceeded the size limits.MultipartStream.MalformedStreamException
- if the stream ends unexpectedly.
-
setBoundary
public void setBoundary(byte[] boundary) throws MultipartStream.IllegalBoundaryException
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.
- Parameters:
boundary
- The boundary to be used for parsing of the nested stream.- Throws:
MultipartStream.IllegalBoundaryException
- if theboundary
has a different length than the one being currently parsed.
-
setHeaderEncoding
public void setHeaderEncoding(java.lang.String encoding)
Specifies the character encoding to be used when reading the headers of individual parts. When not specified, ornull
, the platform default encoding is used.- Parameters:
encoding
- The encoding used to read part headers.
-
setPartHeaderSizeMax
public void setPartHeaderSizeMax(int partHeaderSizeMax)
Sets the per part size limit for headers.- Parameters:
partHeaderSizeMax
- The maximum size of the headers in bytes.- Since:
- 1.6.0
-
skipPreamble
public boolean skipPreamble() throws java.io.IOException
Finds the beginning of the firstencapsulation
.- Returns:
true
if anencapsulation
was found in the stream.- Throws:
java.io.IOException
- if an i/o error occurs.
-
-