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HTTPClient
Class HttpOutputStream  

java.lang.Object
  java.io.OutputStream
      HTTPClient.HttpOutputStream

All Implemented Interfaces:

GlobalConstants

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public class HttpOutputStream

extends java.io.OutputStream

implements GlobalConstants

This class provides an output stream for requests. The stream must first be associated with a request before it may be used; this is done by passing it to one of the request methods in HTTPConnection. Example:

    OutputStream out = new HttpOutputStream(12345);
    rsp = con.Post("/cgi-bin/my_cgi", out);
    out.write(...);
    out.close();
    if (rsp.getStatusCode() >= 300)
        ...
 

There are two constructors for this class, one taking a length parameter, and one without any parameters. If the stream is created with a length then the request will be sent with the corresponding Content-length header and anything written to the stream will be written on the socket immediately. This is the preferred way. If the stream is created without a length then one of two things will happen: if, at the time of the request, the server is known to understand HTTP/1.1 then each write() will send the data immediately using the chunked encoding. If, however, either the server version is unknown (because this is first request to that server) or the server only understands HTTP/1.0 then all data will be written to a buffer first, and only when the stream is closed will the request be sent.

Another reason that using the HttpOutputStream(length) constructor is recommended over the HttpOutputStream() one is that some HTTP/1.1 servers do not allow the chunked transfer encoding to be used when POSTing to a cgi script. This is because the way the cgi API is defined the cgi script expects a Content-length environment variable. If the data is sent using the chunked transfer encoding however, then the server would have to buffer all the data before invoking the cgi so that this variable could be set correctly. Not all servers are willing to do this.

If you cannot use the HttpOutputStream(length) constructor and are having problems sending requests (usually a 411 response) then you can try setting the system property HTTPClient.dontChunkRequests to true (this needs to be done either on the command line or somewhere in the code before the HTTPConnection is first accessed). This will prevent the client from using the chunked encoding in this case and will cause the HttpOutputStream to buffer all the data instead, sending it only when close() is invoked.

The behaviour of a request sent with an output stream may differ from that of a request sent with a data parameter. The reason for this is that the various modules cannot resend a request which used an output stream. Therefore such things as authorization and retrying of requests won't be done by the HTTPClient for such requests.

Since:

V0.3

Version:

0.3-2 18/06/1999

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Field Summary
private  java.io.ByteArrayOutputStream	bos           the buffer to be used if needed
static int	CD_0
static int	CD_CHUNKED
static int	CD_CLOSE
static int	CD_CONTLEN
static int	CD_HDRS
static int	CD_MP_BR
static int	CD_NONE           Content delimiters
private  int	con_to           the timeout to pass to SendRequest()
static boolean	DebugAll           Debug variables
static boolean	DebugAuth
static boolean	DebugConn
static boolean	DebugDemux
static boolean	DebugMods
static boolean	DebugResp
static boolean	DebugSocks
static boolean	DebugURLC
private static NVPair[]	empty           null trailers
static int	HTTP           possible http protocols we (might) handle
static int	HTTP_1_0           some known http versions
static int	HTTP_1_1
static int	HTTP_NG
static int	HTTPS
private  boolean	ignore           just ignore all the data if told to do so
private  int	length           the length of the data to be sent
private  java.io.OutputStream	os           the socket output stream
private  int	rcvd           the length of the data received so far
private  Request	req           the request this stream is associated with
private  Response	resp           the response from sendRequest if we stalled the request
static int	SHTTP
private  NVPair[]	trailers           the trailers to send if using chunked encoding.

 

Constructor Summary

HttpOutputStream()           Creates an output stream of unspecified length.

HttpOutputStream(int length)           This creates an output stream which will take length bytes of data.

 

Method Summary
void	close()           Closes the stream and causes the data to be sent if it has not already been done so.
int	getLength()           Returns the number of bytes this stream is willing to accept, or -1 if it is unbounded.
(package private)  Response	getResponse()           Return the response we got from sendRequest().
NVPair[]	getTrailers()           Gets the trailers which were set with setTrailers().
(package private)  void	goAhead(Request req, java.io.OutputStream os, int con_to)           Associates this stream with a request and the actual output stream.
(package private)  void	ignoreData(Request req)           Setup this stream to dump the data to the great bit-bucket in the sky.
void	setTrailers(NVPair[] trailers)           Sets the trailers to be sent if the output is sent with the chunked transfer encoding.
java.lang.String	toString()           produces a string describing this stream.
void	write(byte[] buf, int off, int len)           Writes an array of bytes on the stream.
void	write(int b)           Writes a single byte on the stream.

 

Methods inherited from class java.io.OutputStream

flush, write

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Field Detail

empty

private static final NVPair[] empty

null trailers

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length

private int length

the length of the data to be sent

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rcvd

private int rcvd

the length of the data received so far

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req

private Request req

the request this stream is associated with

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resp

private Response resp

the response from sendRequest if we stalled the request

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os

private java.io.OutputStream os

the socket output stream

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bos

private java.io.ByteArrayOutputStream bos

the buffer to be used if needed

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trailers

private NVPair[] trailers

the trailers to send if using chunked encoding.

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con_to

private int con_to

the timeout to pass to SendRequest()

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ignore

private boolean ignore

just ignore all the data if told to do so

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DebugAll

public static final boolean DebugAll

Debug variables

See Also:

Constant Field Values

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DebugConn

public static final boolean DebugConn

See Also:

Constant Field Values

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DebugResp

public static final boolean DebugResp

See Also:

Constant Field Values

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DebugDemux

public static final boolean DebugDemux

See Also:

Constant Field Values

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DebugAuth

public static final boolean DebugAuth

See Also:

Constant Field Values

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DebugSocks

public static final boolean DebugSocks

See Also:

Constant Field Values

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DebugMods

public static final boolean DebugMods

See Also:

Constant Field Values

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DebugURLC

public static final boolean DebugURLC

See Also:

Constant Field Values

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HTTP

public static final int HTTP

possible http protocols we (might) handle

See Also:

Constant Field Values

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HTTPS

public static final int HTTPS

See Also:

Constant Field Values

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SHTTP

public static final int SHTTP

See Also:

Constant Field Values

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HTTP_NG

public static final int HTTP_NG

See Also:

Constant Field Values

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HTTP_1_0

public static final int HTTP_1_0

some known http versions

See Also:

Constant Field Values

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HTTP_1_1

public static final int HTTP_1_1

See Also:

Constant Field Values

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CD_NONE

public static final int CD_NONE

Content delimiters

See Also:

Constant Field Values

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CD_HDRS

public static final int CD_HDRS

See Also:

Constant Field Values

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CD_0

public static final int CD_0

See Also:

Constant Field Values

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CD_CLOSE

public static final int CD_CLOSE

See Also:

Constant Field Values

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CD_CONTLEN

public static final int CD_CONTLEN

See Also:

Constant Field Values

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CD_CHUNKED

public static final int CD_CHUNKED

See Also:

Constant Field Values

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CD_MP_BR

public static final int CD_MP_BR

See Also:

Constant Field Values

Constructor Detail

HttpOutputStream

public HttpOutputStream()

Creates an output stream of unspecified length. Note that it is highly recommended that this constructor be avoided where possible and HttpOutputStream(int) used instead.

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HttpOutputStream

public HttpOutputStream(int length)

This creates an output stream which will take length bytes of data.

Method Detail

goAhead

void goAhead(Request req,
             java.io.OutputStream os,
             int con_to)

Associates this stream with a request and the actual output stream. No other methods in this class may be invoked until this method has been invoked by the HTTPConnection.

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ignoreData

void ignoreData(Request req)

Setup this stream to dump the data to the great bit-bucket in the sky. This is needed for when a module handles the request directly.

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getResponse

Response getResponse()

Return the response we got from sendRequest(). This waits until the request has actually been sent.

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getLength

public int getLength()

Returns the number of bytes this stream is willing to accept, or -1 if it is unbounded.

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getTrailers

public NVPair[] getTrailers()

Gets the trailers which were set with setTrailers().

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setTrailers

public void setTrailers(NVPair[] trailers)

Sets the trailers to be sent if the output is sent with the chunked transfer encoding. These must be set before the output stream is closed for them to be sent.

Any trailers set here should be mentioned in a Trailer header in the request (see section 14.40 of draft-ietf-http-v11-spec-rev-06.txt).

This method (and its related getTrailers())) are in this class and not in Request because setting trailers is something an application may want to do, not only modules.

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write

public void write(int b)
           throws java.io.IOException,
                  java.lang.IllegalAccessError

Writes a single byte on the stream. It is subject to the same rules as write(byte[], int, int).

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write

public void write(byte[] buf,
                  int off,
                  int len)
           throws java.io.IOException,
                  java.lang.IllegalAccessError

Writes an array of bytes on the stream. This method may not be used until this stream has been passed to one of the methods in HTTPConnection (i.e. until it has been associated with a request).

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close

public void close()
           throws java.io.IOException,
                  java.lang.IllegalAccessError

Closes the stream and causes the data to be sent if it has not already been done so. This method must be invoked when all data has been written.

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toString

public java.lang.String toString()

produces a string describing this stream.

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