Header(3) User Contributed Perl Documentation Header(3)
NAME
Text::Header - RFC 822/2068 "header" and "unheader" functions
SYNOPSIS
use Text::Header; # header and unheader exported
# Construct headers similar to CGI.pm and HTTP::Headers
@HEADERS = header(content_type => 'text/html',
author => 'Nathan Wiger',
last_modified => $date,
accept => [qw(text/html text/plain)]);
# The above produces the array:
@HEADERS = ("Content-Type: text/html
",
"Author: Nathan Wiger
",
"Last-Modified: Wed Sep 27 13:31:06 PDT 2000
",
"Accept: text/html, text/plain
");
# Can also construct SMTP headers to format mail
@mail_headers = header(from => 'Nathan Wiger <nate@sun.com>',
to => 'perl5-porters@perl.org');
print $MAIL @mail_headers, "
Keep up the great work!
";
# The above would print this to the $MAIL handle:
From: Nathan Wiger <nate@sun.com>
To: perl5-porters@perl.org
Keep up the great work!
DESCRIPTION
This module provides two new functions, "header" and "unheader", which provide general-purpose RFC 822 header construction and parsing.
They do not provide any intelligent defaults of HTTP-specific methods. They are simply aimed at providing an easy means to address the
mechanics of header parsing.
The output style is designed to mimic "CGI.pm" and "HTTP::Headers", so that users familiar with these interfaces will feel at home with
these functions. As shown above, the "headers" function automatically does the following:
1. uc's the first letter of each tag token and lc's the
rest, also converting _'s to -'s automatically
2. Adds a colon separating each tag and its value, and
exactly one newline after each one
3. Combines list elements into a comma-delimited
string
Note that a list is always joined into a comma-delimited string. To insert multiple separate headers, simply call "header" with multiple
args:
push @out, header(accept => 'text/html',
accept => 'text/plain');
This would create multiple "Accept:" lines.
Note that unlike "CGI.pm", the "header" function provided here does not provide any intelligent defaults. If called as:
@out_headers = header;
It will return an empty list. This allows "header" to be more general pupose, so it can provide SMTP and other headers as well. You can
also use it as a generic text formatting tool, hence the reason it's under the "Text::" hierarchy.
The "unheader" function works in exactly the opposite direction from "header", pulling apart headers and returning a list. "unheader":
1. lc's the entire tag name, converting -'s to _'s
2. Separates each tag based on the colon delimiter,
chomping newlines.
3. Returns a list of tag/value pairs for easy assignment
to a hash
So, assuming the @HEADERS array shown up top:
%myheaders = unheader(@HEADERS);
The hash %myheaders would have the following values:
%myheaders = (
content_type => 'text/html',
author => 'Nathan Wiger',
last_modified => 'Wed Sep 27 13:31:06 PDT 2000',
accept => 'text/html, text/plain'
);
Note that all keys are converted to lowercase, and their values have their newlines stripped. However, note that comma-separated fields are
not split up on input. This cannot be done reliably because some fields, such as the HTTP "Date:" header, can contain commas even though
they are not lists. Inferring this type of structure would require knowledge of content, and these functions are specifically designed to
be content-independent.
The "unheader" function will respect line wrapping, as seen in SMTP headers. It will simply join the lines and return the value, so that:
%mail = unheader("To: Nathan Wiger <nate@sun.com>,
perl5-porters@perl.org");
Would return:
$mail{to} = "Nathan Wiger <nate@sun.com>, perl5-porters@perl.org"
Notice that multiple spaces between the comma separator have been condensed to a single space. Since the "header" and "unheader" functions
are direct inverses, this call:
@out = header unheader @in;
Will result in @out being exactly equivalent to @in.
REFERENCES
This is designed as both a Perl 5 module and also a Perl 6 prototype. Please see the Perl 6 proposal at http://dev.perl.org/rfc/333.html
This module is designed to be fully compliant with the internet standards RFC 822 (SMTP Headers) and RFC 2068 (HTTP Headers).
AUTHOR
Copyright (c) 2000 Nathan Wiger <nate@sun.com>. All Rights Reserved.
This module is free software; you may copy this under the terms of the GNU General Public License, or the Artistic License, copies of which
should have accompanied your Perl kit.
perl v5.8.2 2003-12-23 Header(3)