vmod_header

Varnish Header Module

Manual section

3

Author

Kristian Lyngstøl

Date

2011-08-12

Version

0.3

SYNOPSIS

import header;

header.append(<header>, <content>)
header.get(<header>, <regular expression>)
header.remove(<header>, <regular expression>)
header.copy(<source header>, <destination header>)
header.version()

DESCRIPTION

Varnish Module (vmod) for manipulation of duplicated headers (for instance multiple set-cookie headers).

FUNCTIONS

Example VCL:

backend foo { ... };

import header;

sub vcl_fetch {
    header.append(beresp.http.Set-Cookie,"foo=bar");
            header.remove(beresp.http.Set-Cookie,"dontneedthiscookie");
}

append

Prototype

header.append(<header>, <content>)

Returns

void

Description

Append lets you add an extra occurrence of an existing header.

Example

header.append(beresp.http.Set-Cookie,"foo=bar")

get

Prototype

header.get(<header>, <regular expression>)

Returns

String

Description

Get fetches the value of the first header that matches the given regular expression.

Example

set beresp.http.xusr = header.get(beresp.http.set-cookie,"user=");

remove

Prototype

header.remove(<header>, <regular expression>)

Returns

void

Description

remove() removes all occurences of header that matches the given regular expression. The example is a white-list of "funcookie=".

Example

header.remove(beresp.http.set-cookie,"^(?!(funcookie=))");

copy

Prototype

header.copy(<source header>, <destination header>)

Returns

void

Description

Copies all of the source headers to a new header.

Example

header.copy(beresp.http.set-cookie, beresp.http.x-old-cookie);

version

Prototype

header.version()

Returns

string

Description

Returns the string constant version-number of the header vmod.

Example

set resp.http.X-header-version = header.version();

INSTALLATION

Installation requires the Varnish source tree (only the source matching the binary installation).

1. ./autogen.sh (for git-installation)
2. ./configure VARNISHSRC=/path/to/your/varnish/source/varnish-cache
3. make
4. make install (may require root: sudo make install)
5. make check (Optional for regression tests)

VARNISHSRC is the directory of the Varnish source tree for which to compile your vmod. Both the VARNISHSRC and VARNISHSRC/include will be added to the include search paths for your module.

Optionally you can also set the vmod install dir by adding VMODDIR=DIR (defaults to the pkg-config discovered directory from your Varnish installation).

ACKNOWLEDGEMENTS

The development of this plugin was made possible by the sponsorship of Softonic, http://en.softonic.com/ .

Author: Kristian Lyngstøl <kristian@varnish-software.com>, Varnish Software AS Skeleton by Martin Blix Grydeland <martin@varnish-software.com>, vmods are part of Varnish Cache 3.0 and beyond.

Also thanks to: Imo Klabun and Anders Nordby for bug reports.

HISTORY

Version 0.1: Initial version, somewhat ambiguous where it starts and ends.

Version 0.2: Bug fixes for string removal

Version 0.3: Bug fixes for get/remove, add version()

BUGS

You can't use dynamic regular expressions, which also holds true for normal regular expressions in regsub(), but VCL isn't able to warn you about this when it comes to vmods yet.

Some overlap with varnishd exists, this will be mended as Varnish 3.0 evolves.

SEE ALSO

• varnishd(1)
• vcl(7)
• https://github.com/varnish/libvmod-header

COPYRIGHT

This document is licensed under the same license as the libvmod-header project. See LICENSE for details.

• Copyright (c) 2011-2013 Varnish Software