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 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 }
Definition at line 134 of file MultipartStream.java.
Public Member Functions | |
MultipartStream () | |
Default constructor. | |
MultipartStream (InputStream input, byte[] boundary, int bufSize) | |
MultipartStream (InputStream input, byte[] boundary) throws IOException | |
String | getHeaderEncoding () |
Retrieves the character encoding used when reading the headers of an individual part. | |
void | setHeaderEncoding (String encoding) |
Specifies the character encoding to be used when reading the headers of individual parts. | |
byte | readByte () throws IOException |
Reads a byte from the buffer , and refills it as necessary. | |
boolean | readBoundary () throws MalformedStreamException |
Skips a boundary token, and checks whether more encapsulations are contained in the stream. | |
void | setBoundary (byte[] boundary) throws IllegalBoundaryException |
String | readHeaders () throws MalformedStreamException |
int | readBodyData (OutputStream output) throws MalformedStreamException, IOException |
int | discardBodyData () throws MalformedStreamException, IOException |
boolean | skipPreamble () throws IOException |
Finds the beginning of the first encapsulation . | |
String | toString () |
Returns a string representation of this object. | |
Static Public Member Functions | |
static boolean | arrayequals (byte[] a, byte[] b, int count) |
Compares count first bytes in the arrays a and b . | |
Static Public Attributes | |
static final int | HEADER_PART_SIZE_MAX = 10240 |
The maximum length of header-part that will be processed (10 kilobytes = 10240 bytes. | |
Protected Member Functions | |
int | findByte (byte value, int pos) |
Searches for a byte of specified value in the buffer , starting at the specified position . | |
int | findSeparator () |
Searches for the boundary in the buffer region delimited by head and tail . | |
Static Protected Attributes | |
static final int | DEFAULT_BUFSIZE = 4096 |
The default length of the buffer used for processing a request. | |
static final byte[] | HEADER_SEPARATOR = {0x0D, 0x0A, 0x0D, 0x0A} |
A byte sequence that marks the end of header-part (CRLFCRLF ). | |
static final byte[] | FIELD_SEPARATOR = { 0x0D, 0x0A } |
A byte sequence that that follows a delimiter that will be followed by an encapsulation (CRLF ). | |
static final byte[] | STREAM_TERMINATOR = { 0x2D, 0x2D } |
A byte sequence that that follows a delimiter of the last encapsulation in the stream (-- ). | |
Classes | |
class | IllegalBoundaryException |
Thrown upon attempt of setting an invalid boundary token. More... | |
class | MalformedStreamException |
Thrown to indicate that the input stream fails to follow the required syntax. More... |
org.apache.commons.fileupload.MultipartStream.MultipartStream | ( | ) |
Default constructor.
MultipartStream(InputStream, byte[])
Definition at line 246 of file MultipartStream.java.
org.apache.commons.fileupload.MultipartStream.MultipartStream | ( | InputStream | input, | |
byte[] | boundary, | |||
int | bufSize | |||
) |
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.
input | The InputStream to serve as a data source. | |
boundary | The token used for dividing the stream into encapsulations . | |
bufSize | The size of the buffer to be used, in bytes. |
MultipartStream(InputStream, byte[])
Definition at line 269 of file MultipartStream.java.
org.apache.commons.fileupload.MultipartStream.MultipartStream | ( | InputStream | input, | |
byte[] | boundary | |||
) | throws IOException |
Constructs a MultipartStream
with a default size buffer.
input | The InputStream to serve as a data source. | |
boundary | The token used for dividing the stream into encapsulations . |
IOException | when an error occurs. |
MultipartStream(InputStream, byte[], int)
Definition at line 306 of file MultipartStream.java.
References org.apache.commons.fileupload.MultipartStream.DEFAULT_BUFSIZE.
String org.apache.commons.fileupload.MultipartStream.getHeaderEncoding | ( | ) |
Retrieves the character encoding used when reading the headers of an individual part.
When not specified, or null
, the platform default encoding is used.
Definition at line 325 of file MultipartStream.java.
void org.apache.commons.fileupload.MultipartStream.setHeaderEncoding | ( | String | encoding | ) |
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.
encoding | The encoding used to read part headers. |
Definition at line 338 of file MultipartStream.java.
Referenced by org.apache.commons.fileupload.FileUploadBase.parseRequest().
byte org.apache.commons.fileupload.MultipartStream.readByte | ( | ) | throws IOException |
Reads a byte from the buffer
, and refills it as necessary.
IOException | if there is no more data available. |
Definition at line 352 of file MultipartStream.java.
Referenced by org.apache.commons.fileupload.MultipartStream.readBoundary(), and org.apache.commons.fileupload.MultipartStream.readHeaders().
boolean org.apache.commons.fileupload.MultipartStream.readBoundary | ( | ) | throws MalformedStreamException |
Skips a boundary
token, and checks whether more encapsulations
are contained in the stream.
true
if there are more encapsulations in this stream; false
otherwise.MalformedStreamException | if the stream ends unexpecetedly or fails to follow required syntax. |
Definition at line 381 of file MultipartStream.java.
References org.apache.commons.fileupload.MultipartStream.arrayequals(), org.apache.commons.fileupload.MultipartStream.FIELD_SEPARATOR, org.apache.commons.fileupload.MultipartStream.readByte(), and org.apache.commons.fileupload.MultipartStream.STREAM_TERMINATOR.
Referenced by org.apache.commons.fileupload.FileUploadBase.parseRequest(), and org.apache.commons.fileupload.MultipartStream.skipPreamble().
void org.apache.commons.fileupload.MultipartStream.setBoundary | ( | byte[] | boundary | ) | throws 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.
boundary | The boundary to be used for parsing of the nested stream. |
IllegalBoundaryException | if the boundary has a different length than the one being currently parsed. |
Definition at line 433 of file MultipartStream.java.
Referenced by org.apache.commons.fileupload.FileUploadBase.parseRequest().
String org.apache.commons.fileupload.MultipartStream.readHeaders | ( | ) | throws MalformedStreamException |
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.
header-part
of the current encapsulation.MalformedStreamException | if the stream ends unexpecetedly. |
Definition at line 460 of file MultipartStream.java.
References org.apache.commons.fileupload.MultipartStream.HEADER_PART_SIZE_MAX, org.apache.commons.fileupload.MultipartStream.HEADER_SEPARATOR, and org.apache.commons.fileupload.MultipartStream.readByte().
Referenced by org.apache.commons.fileupload.FileUploadBase.parseRequest().
int org.apache.commons.fileupload.MultipartStream.readBodyData | ( | OutputStream | output | ) | throws MalformedStreamException, IOException |
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 constructor).
output | The Stream to write data into. |
MalformedStreamException | if the stream ends unexpectedly. | |
IOException | if an i/o error occurs. |
Definition at line 533 of file MultipartStream.java.
References org.apache.commons.fileupload.MultipartStream.findSeparator().
Referenced by org.apache.commons.fileupload.FileUploadBase.parseRequest().
int org.apache.commons.fileupload.MultipartStream.discardBodyData | ( | ) | throws MalformedStreamException, IOException |
Reads body-data
from the current encapsulation
and discards it.
Use this method to skip encapsulations you don't need or don't understand.
MalformedStreamException | if the stream ends unexpectedly. | |
IOException | if an i/o error occurs. |
Definition at line 612 of file MultipartStream.java.
References org.apache.commons.fileupload.MultipartStream.findSeparator().
Referenced by org.apache.commons.fileupload.FileUploadBase.parseRequest(), and org.apache.commons.fileupload.MultipartStream.skipPreamble().
boolean org.apache.commons.fileupload.MultipartStream.skipPreamble | ( | ) | throws IOException |
Finds the beginning of the first encapsulation
.
true
if an encapsulation
was found in the stream.IOException | if an i/o error occurs. |
Definition at line 681 of file MultipartStream.java.
References org.apache.commons.fileupload.MultipartStream.discardBodyData(), and org.apache.commons.fileupload.MultipartStream.readBoundary().
Referenced by org.apache.commons.fileupload.FileUploadBase.parseRequest().
static boolean org.apache.commons.fileupload.MultipartStream.arrayequals | ( | byte[] | a, | |
byte[] | b, | |||
int | count | |||
) | [static] |
Compares count
first bytes in the arrays a
and b
.
a | The first array to compare. | |
b | The second array to compare. | |
count | How many bytes should be compared. |
true
if count
first bytes in arrays a
and b
are equal. Definition at line 722 of file MultipartStream.java.
Referenced by org.apache.commons.fileupload.MultipartStream.readBoundary().
int org.apache.commons.fileupload.MultipartStream.findByte | ( | byte | value, | |
int | pos | |||
) | [protected] |
Searches for a byte of specified value in the buffer
, starting at the specified position
.
value | The value to find. | |
pos | The starting position for searching. |
buffer
, or -1
if not found. Definition at line 747 of file MultipartStream.java.
Referenced by org.apache.commons.fileupload.MultipartStream.findSeparator().
int org.apache.commons.fileupload.MultipartStream.findSeparator | ( | ) | [protected] |
Searches for the boundary
in the buffer
region delimited by head
and tail
.
buffer
, or -1
if not found. Definition at line 770 of file MultipartStream.java.
References org.apache.commons.fileupload.MultipartStream.findByte().
Referenced by org.apache.commons.fileupload.MultipartStream.discardBodyData(), and org.apache.commons.fileupload.MultipartStream.readBodyData().
String org.apache.commons.fileupload.MultipartStream.toString | ( | ) |
Returns a string representation of this object.
Definition at line 804 of file MultipartStream.java.
final int org.apache.commons.fileupload.MultipartStream.HEADER_PART_SIZE_MAX = 10240 [static] |
The maximum length of header-part
that will be processed (10 kilobytes = 10240 bytes.
).
Definition at line 144 of file MultipartStream.java.
Referenced by org.apache.commons.fileupload.MultipartStream.readHeaders().