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'\" $Header: /cvsroot/aolserver/aolserver/doc/Ns_ConnSetHeaders.3,v 1.1 2006/04/19 17:37:30 jgdavidson Exp $
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.TH Ns_ConnSetHeaders 3aolserver 4.0 AOLserver "AOLserver Library Procedures"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
Ns_ConnCondSetHeaders, Ns_ConnSetExpiresHeader, Ns_ConnSetHeaders, Ns_ConnSetLastModifiedHeader, Ns_ConnSetLengthHeader, Ns_ConnSetRequiredHeaders \- Routines to manage response headers 
.SH SYNOPSIS
.nf
\fB#include "ns.h"\fR
.sp
void
\fBNs_ConnCondSetHeaders\fR(\fIconn, key, value\fR)
.sp
void
\fBNs_ConnSetExpiresHeader\fR(\fIconn, expires\fR)
.sp
void
\fBNs_ConnSetHeaders\fR(\fIconn, key, value\fR)
.sp
void
\fBNs_ConnSetLastModifiedHeader\fR(\fIconn, mtime\fR)
.sp
void
\fBNs_ConnSetLengthHeader\fR(\fIconn, length\fR)
.sp
void
\fBNs_ConnSetRequiredHeaders\fR(\fIconn, type, length\fR)
.sp
void
\fBNs_ConnSetTypeHeader\fR(\fIconn, type\fR)
.SH ARGUMENTS
.AS Ns_Conn conn in
.AP Ns_Conn conn in
Pointer to open connection.
.AP char *expires in
Pointer to string to construct an \fIexpires\fR header.
.AP char *key in
Pointer to string key for a header.
.AP int length in
Integer length of output content to construct a \fIcontent-length\fR header.
.AP time_t mtime in
Modification time stamp to construct a \fIlast-modified\fR header.
.AP int status in
HTTP result status code.
.AP char *type in
Pointer to mimetype string to construct a \fIcontent-type\fR header.
.AP char *value in
Pointer to a string value for a header.
.BE

.SH DESCRIPTION
.PP
These functions manage the output headers eventually sent through
the given open connection to a client.  They operate by modifying
the \fIoutputheaders\fR Ns_Set of the connection Ns_Conn structure.
Headers can be modified until they are queued or sent directly via
the \fBNs_ConnQueueHeaders\fR or \fBNs_ConnFlushHeaders\fR routines.
It is possible to modify the \fIoutputheaders\fR directly although
use of these functions is preferred for consistancy.

.PP
Note that higher level output routines such as \fBNs_ConnFlush\fR
or the various \fBNs_ConnReturn\fR routines normally generate all
the headers necessary for a given response.  These routines are
normally only necessary for specialized applications which output
additional specific headers or specialized request procedures which
do not use the higher level output routines.

.TP
void \fBNs_ConnCondSetHeaders\fR(\fIconn, key, value\fR)
Append an output header of the form \fIkey: value\fR only if the
header does not already exist in the \fIoutputheaders\fR set.

.TP
void \fBNs_ConnSetExpiresHeader\fR(\fIconn, expires\fR)
This routine is equivalent to \fBNs_ConnSetHeaders\fR(\fIconn,
"Expires", expires\fR).  Note that the \fIexires\fR parameter is
treated as a string, not a timestamp.  A timestamp can be constructed
with the \fBNs_HttpTime\fR routine.

.TP
void \fBNs_ConnSetHeaders\fR(\fIconn, key, value\fR)
Append a header of the form \fIkey: value\fR to the \fIoutputheaders\fR.
This routine will append a new, possibly duplicate, header regardless
of whether a matching header already exists in the \fIoutputheaders\fR.

.TP
void \fBNs_ConnSetLastModifiedHeader\fR(\fIconn, mtime\fR)
This routine appends a \fIlast-modified\fR header if one does not
already exists, formatting the given modification time as a proper
HTTP timestamp with the \fBNs_HttpTime\fR routine.

.TP
void \fBNs_ConnSetLengthHeader\fR(\fIconn, length\fR)
This routine appends a \fIcontent-length: length\fR header, formatting
the given integer length as a string.  This routine will also record
the response length internally in the \fIconn\fR structure so that
it can be later retrieved via the \fBNs_ConnResponseLength\fR
routine, for example, as part of a post-connection logging callback.

.TP
void \fBNs_ConnSetRequiredHeaders\fR(\fIconn, type, length\fR)
This routine appends the basic headers normally required for a
proper HTTP transaction.  These include \fImime-version\fR, \fIdate\fR,
and \fIserver\fR as well as the \fIcontent-type: type\fR and
\fIcontent-length: length\fR headers for the given arguments.  If
\fItype\fR is NULL or \fIlength\fR is less than zero, the corresponding
headers will not be appended.  This routine is often the only header
construction routine necessary for request procedures which construct
headers manually instead of calling routines such as \fBNs_ConnFlush\fR
which handle header construction and queueing automatically.

.TP
void \fBNs_ConnSetTypeHeader\fR(\fIconn, type\fR)
This routine is equivalent to \fBNs_ConnSetHeaders\fR(\fIconn,
"content-type", type\fR).

.SH "SEE ALSO"
Ns_ConnQueueHeaders(3), Ns_ConnFlushHeaders(3), Ns_ConnFlush(3)

.SH KEYWORDS
headers, response