Ubuntu Manpage: Ns_ConnFlush, Ns_ConnFlushDirect - Flush content to an open connection

Provided by: aolserver4-dev_4.5.1-16_amd64

NAME

       Ns_ConnFlush, Ns_ConnFlushDirect - Flush content to an open connection

SYNOPSIS

       #include "ns.h"

       int
       Ns_ConnFlush(conn, buf, len, stream)

       int
       Ns_ConnFlushDirect(conn, buf, len, stream)

ARGUMENTS

       char      *buf   (in)      Pointer to buffer to send.

       Ns_Conn   conn   (in)      Pointer to current connection.

       int       len    (in)      Length of bytes pointed to by buf.

       int       stream (in)      Boolean value to indicate a streamed response.
_________________________________________________________________

DESCRIPTION

These routines support sending content to the client through the connection's communcation driver. They
support generating both complete single responses or streaming content through multiple calls. They both
take a pointer to the current connection specified by the conn argument and a pointer to content to send
specified by buf of length len. If len is negative, buf is assumed to be a null terminated string and
len is calculated by strlen.

The stream argument, if zero, indicates a single response should be generated. In this case, an
appropriate content-length header is generated, the content is sent, and the connection is closed with
Ns_ConnClose. If stream is not zero, the call is assumed to be one of potential multiple calls which
will send content incrementally to the client. Content streamed in this case is sent either in chunked
encoding mode for HTTP/1.1 clients or directly, without a content-length as was common in pre-HTTP/1.1
applications. Applications which stream content should be sure to make a final call Ns_ConnFlush or
Ns_ConnFlushDirect with stream set to zero to correctly flush and close the connection.

The Ns_ConnFlush and Ns_ConnFlushDirect differ in their treatment of the given content before sending.
Ns_ConnFlushDirect does not alter the content in anyway, treating is as an arbitrary array of bytes.
Ns_ConnFlush assumes the content is UTF-8 text, e.g., the result of an ADP page execution. In this case,
if the connection has an associated output encoding set with the Ns_ConnSetEncoding routine, it will be
used to encode the content in the requested character set (e.g., from UTF-8 to iso8859-1). In addition,
if the server has gzip compression enabled, the nszlib module is loaded, the connection has been marked
for gzip compression with the Ns_ConnSetGzipFlag, and the size of the output data is greater than the
server configured minimun gzip compression size, the content will be compressed and an appropriate header
will be generated for the client. Gzip compression is not supported when content is streamed to the
client.

The first call to Ns_ConnFlush or Ns_ConnFlushDirect for a connection, in stream or single response mode,
will result in appropriate headers being constructed and sent first before any user data. These headers
include the basic headers constructed via Ns_ConnSetRequiredHeaders plus any additional application
specific headers queued for output via Ns_ConnSetHeaders or Ns_ConnCondSetHeaders. The Ns_ConnFlush
routine may add additional headers as needed to specify chunked and/or gzip encoding.

EXAMPLE

       The following example generates a simple text response:

                Ns_ConnSetStatus(conn, 200);
                Ns_ConnSetType(conn, "text/plain");
                Ns_ConnFlush(conn, "Hello", 5, 0);

       The following example demonstrates streaming:

                Ns_ConnSetStatus(conn, 200);
                Ns_ConnSetType(conn, "text/plain");
                for (i = 0; i < 10; ++i) {
                   sprintf(buf, "stream: %d0, i);
                   Ns_ConnFlush(conn, buf, -1, 1);
                }
                Ns_ConnFlush(conn, "done!", 5, 0);

KEYWORDS