151 lines
4.8 KiB
HTML
151 lines
4.8 KiB
HTML
<HTML>
|
|
<HEAD><TITLE>smfi_insheader</TITLE></HEAD>
|
|
<BODY>
|
|
<!--
|
|
$Id: smfi_insheader.html,v 1.11 2013/11/22 20:51:39 ca Exp $
|
|
-->
|
|
<H1>smfi_insheader</H1>
|
|
|
|
<TABLE border="0" cellspacing=4 cellpadding=4>
|
|
<!---------- Synopsis ----------->
|
|
<TR><TH valign="top" align=left width=100>SYNOPSIS</TH><TD>
|
|
<PRE>
|
|
#include <libmilter/mfapi.h>
|
|
int smfi_insheader(
|
|
SMFICTX *ctx,
|
|
int hdridx,
|
|
char *headerf,
|
|
char *headerv
|
|
);
|
|
</PRE>
|
|
Prepend a header to the current message.
|
|
</TD></TR>
|
|
|
|
<!----------- Description ---------->
|
|
<TR><TH valign="top" align=left>DESCRIPTION</TH><TD>
|
|
<TABLE border="1" cellspacing=1 cellpadding=4>
|
|
<TR align="left" valign=top>
|
|
<TH width="80">Called When</TH>
|
|
<TD>Called only from <A href="xxfi_eom.html">xxfi_eom</A>.</TD>
|
|
</TR>
|
|
<TR align="left" valign=top>
|
|
<TH width="80">Effects</TH>
|
|
<TD>Prepends a header to the current message.</TD>
|
|
</TR>
|
|
</TABLE>
|
|
|
|
<!----------- Arguments ---------->
|
|
<TR><TH valign="top" align=left>ARGUMENTS</TH><TD>
|
|
<TABLE border="1" cellspacing=0>
|
|
<TR bgcolor="#dddddd"><TH>Argument</TH><TH>Description</TH></TR>
|
|
<TR valign="top"><TD>ctx</TD>
|
|
<TD>Opaque context structure.
|
|
</TD></TR>
|
|
<TR valign="top"><TD>hdridx</TD>
|
|
<TD>The location in the internal header list where this header should
|
|
be inserted; 0 makes it the topmost header, etc.
|
|
</TD></TR>
|
|
<TR valign="top"><TD>headerf</TD>
|
|
<TD>The header name, a non-NULL, null-terminated string.
|
|
</TD></TR>
|
|
<TR valign="top"><TD>headerv</TD>
|
|
<TD>The header value to be added, a non-NULL, null-terminated string. This may be the empty string.
|
|
</TD></TR>
|
|
</TABLE>
|
|
</TD></TR>
|
|
|
|
<!----------- Return values ---------->
|
|
<TR>
|
|
<TH valign="top" align=left>RETURN VALUES</TH>
|
|
|
|
<TD>smfi_insheader returns MI_FAILURE if:
|
|
<UL><LI>headerf or headerv is NULL.
|
|
<LI>Adding headers in the current connection state is invalid.
|
|
<LI>Memory allocation fails.
|
|
<LI>A network error occurs.
|
|
<LI>SMFIF_ADDHDRS was not set when <A href="smfi_register.html">smfi_register</A> was called.
|
|
</UL>
|
|
Otherwise, it returns MI_SUCCESS.
|
|
</TD>
|
|
</TR>
|
|
|
|
<!----------- Notes ---------->
|
|
<TR align="left" valign=top>
|
|
<TH>NOTES</TH>
|
|
<TD>
|
|
<UL>
|
|
<LI>smfi_insheader does not change a message's existing headers.
|
|
To change a header's current value, use
|
|
<A HREF="smfi_chgheader.html">smfi_chgheader</A>.
|
|
<LI>A filter which calls smfi_insheader must have set the SMFIF_ADDHDRS
|
|
flag in the smfiDesc_str passed to
|
|
<A href="smfi_register.html">smfi_register</A>.
|
|
<LI>For smfi_insheader, filter order is important.
|
|
<B>Later filters will see the header changes made by earlier ones.</B>
|
|
<LI>A filter will receive <EM>only</EM> headers that have been sent
|
|
by the SMTP client and those header modifications by earlier filters.
|
|
It will <EM>not</EM> receive the headers that are inserted by sendmail
|
|
itself.
|
|
This makes the header insertion position highly dependent on
|
|
the headers that exist in the incoming message
|
|
and those that are configured to be added by sendmail.
|
|
For example, sendmail will always add a
|
|
<CODE>Received:</CODE> header to the beginning of the headers.
|
|
Setting <CODE>hdridx</CODE> to 0 will actually insert the header
|
|
before this <CODE>Received:</CODE> header.
|
|
However, later filters can be easily confused as they receive
|
|
the added header, but not the <CODE>Received:</CODE> header,
|
|
thus making it hard to insert a header at a fixed position.
|
|
<LI>If hdridx is a number larger than the number of headers in the message,
|
|
the header will simply be appended.
|
|
<LI>Neither the name nor the value of the header is checked for
|
|
standards compliance.
|
|
However, each line of the header must be under 2048 characters
|
|
and should be under 998 characters.
|
|
If longer headers are needed, make them multi-line.
|
|
To make a multi-line header,
|
|
insert a line feed (ASCII 0x0a, or <TT>\n</TT> in C)
|
|
followed by at least one whitespace character
|
|
such as a space (ASCII 0x20) or tab (ASCII 0x09, or <TT>\t</TT> in C).
|
|
The line feed should NOT be preceded by a carriage return (ASCII 0x0d);
|
|
the MTA will add this automatically.
|
|
<B>It is the filter writer's responsibility to ensure that no standards
|
|
are violated.</B>
|
|
<LI>The MTA adds a leading space to an inserted header value unless
|
|
the flag
|
|
<A HREF="xxfi_negotiate.html#SMFIP_HDR_LEADSPC"><CODE>SMFIP_HDR_LEADSPC</CODE></A>
|
|
is set, in which case the milter
|
|
must include any desired leading spaces itself.
|
|
</UL>
|
|
</TD>
|
|
</TR>
|
|
|
|
<!----------- Example code ---------->
|
|
<TR>
|
|
<TH valign="top" align=left>EXAMPLE</TH>
|
|
|
|
<TD>
|
|
<PRE>
|
|
int ret;
|
|
SMFICTX *ctx;
|
|
|
|
...
|
|
|
|
ret = smfi_insheader(ctx, 0, "First", "See me?");
|
|
</PRE>
|
|
</TD>
|
|
</TR>
|
|
|
|
</TABLE>
|
|
|
|
<HR size="1">
|
|
<FONT size="-1">
|
|
Copyright (c) 2004, 2006, 2009 Proofpoint, Inc. and its suppliers.
|
|
All rights reserved.
|
|
<BR>
|
|
By using this file, you agree to the terms and conditions set
|
|
forth in the LICENSE.
|
|
</FONT>
|
|
</BODY>
|
|
</HTML>
|