NAME

vmod_cookie - Varnish Cookie Module

SYNOPSIS

import cookie [as name] [from "path"]
VOID clean()
VOID delete(STRING cookiename)
VOID filter(STRING filterstring)
VOID filter_re(REGEX expression)
VOID keep(STRING filterstring)
VOID keep_re(REGEX expression)
STRING format_date(TIME now, DURATION timedelta)
STRING get(STRING cookiename)
STRING get_re(REGEX expression)
STRING get_string()
BOOL isset(STRING cookiename)
VOID parse(STRING cookieheader)
VOID set(STRING cookiename, STRING value)

DESCRIPTION

Handle HTTP cookies more easily in Varnish VCL.

Parses a cookie header into an internal data store, where per-cookie get/set/delete functions are available. A keep() function removes all but a set comma-separated list of cookies. A filter() function removes a comma- separated list of cookies.

Regular expressions can be used for either selecting cookies, deleting matching cookies and deleting non-matching cookie names.

A convenience function for formatting the Set-Cookie Expires date field is also included.

The state loaded with cookie.parse() has a lifetime of the current request or backend request context. To pass variables to the backend request, store the contents as fake bereq headers.

Filtering example:

import cookie;
sub vcl_recv {
    if (req.http.cookie) {
        cookie.parse(req.http.cookie);
        # Either delete the ones you want to get rid of:
        cookie.delete("cookie2");
        # or delete all but a few:
        cookie.keep("SESSIONID,PHPSESSID");
        # Store it back into req so it will be passed to the backend.
        set req.http.cookie = cookie.get_string();
        # If empty, unset so the builtin VCL can consider it for caching.
        if (req.http.cookie == "") {
            unset req.http.cookie;
        }
    }
}

VOID clean()

Clean up previously parsed cookies. It is not necessary to run clean() in normal operations.

Example:

sub vcl_recv {
    cookie.clean();
}

VOID delete(STRING cookiename)

Delete cookiename from internal vmod storage if it exists.

Example:

sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2;");
    cookie.delete("cookie2");
    # get_string() will now yield "cookie1: value1";
}

VOID filter(STRING filterstring)

Delete all cookies from internal vmod storage that are in the comma-separated argument cookienames.

Example:

sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2; cookie3: value3");
    cookie.filter("cookie1,cookie2");
    # get_string() will now yield
    # "cookie3: value3";
}

VOID filter_re(REGEX expression)

Delete all cookies from internal vmod storage that matches the regular expression expression.

Example:

sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2; cookie3: value3");
    cookie.filter_re("^cookie[12]$");
    # get_string() will now yield
    # "cookie3: value3";
}

VOID keep(STRING filterstring)

Delete all cookies from internal vmod storage that is not in the comma-separated argument cookienames.

Example:

sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2; cookie3: value3");
    cookie.keep("cookie1,cookie2");
    # get_string() will now yield
    # "cookie1: value1; cookie2: value2;";
}

VOID keep_re(REGEX expression)

Delete all cookies from internal vmod storage that does not match expression expression.

Example:

sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2; cookie3: value3");
    cookie.keep_re("^cookie[12]$");
    # get_string() will now yield
    # "cookie1: value1; cookie2: value2;";
}

STRING format_date(TIME now, DURATION timedelta)

Get a RFC1123 formatted date string suitable for inclusion in a Set-Cookie response header.

Care should be taken if the response has multiple Set-Cookie headers. In that case the header vmod should be used.

Example:

sub vcl_deliver {
    # Set a userid cookie on the client that lives for 5 minutes.
    set resp.http.Set-Cookie = "userid=" + req.http.userid +
        "; Expires=" + cookie.format_date(now, 5m) + "; httpOnly";
}

STRING get(STRING cookiename)

Get the value of cookiename, as stored in internal vmod storage.

Example:

import std;
sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2;");
    std.log("cookie1 value is: " + cookie.get("cookie1"));
}

If cookiename does not exist, the NULL string is returned. Note that a NULL string is converted to an empty string when assigned to a header. This means that the following is correct:

if (req.http.Cookie) {
        cookie.parse(req.http.Cookie);
        set req.http.X-tmp = cookie.get("a_cookie");
} else {
        set req.http.X-tmp = "";
}
if (req.http.X-tmp != "") {
        // do something with the X-tmp header...
} else {
        // fallback case
}

However, using cookie.isset() is often a better way to check if a particular cookie is present, like this:

unset req.http.X-tmp; # unnecessary if no fallback is needed
if (req.http.Cookie) {
        cookie.parse(req.http.Cookie);
        if (cookie.isset("a_cookie")) {
                set req.http.X-tmp = cookie.get("a_cookie");
                # do something with the X-tmp header...
        }
}
# if necessary, do something when a_cookie is not there
if (!req.http.X-tmp) {
        # fallback case
}

STRING get_re(REGEX expression)

Get the value of the first cookie in internal vmod storage that matches the regular expression expression. If nothing matches, the NULL string is returned.

Example:

import std;
sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2;");
    std.log("cookie1 value is: " + cookie.get_re("^cookie1$"));
}

STRING get_string()

Get a Cookie string value with all cookies in internal vmod storage. Does not modify internal storage.

Example:

sub vcl_recv {
    cookie.parse(req.http.cookie);
    cookie.keep("SESSIONID,PHPSESSID");
    set req.http.cookie = cookie.get_string();
}

BOOL isset(STRING cookiename)

Check if cookiename is set in the internal vmod storage.

Example:

import std;
sub vcl_recv {
    cookie.parse("cookie1: value1; cookie2: value2;");
    if (cookie.isset("cookie2")) {
        std.log("cookie2 is set.");
    }
}

VOID parse(STRING cookieheader)

Parse the cookie string in cookieheader. If state already exists, clean() will be run first.

Example:

sub vcl_recv {
    cookie.parse(req.http.Cookie);
}

VOID set(STRING cookiename, STRING value)

Set the internal vmod storage for cookiename to value.

Example:

sub vcl_recv {
    cookie.set("cookie1", "value1");
    std.log("cookie1 value is: " + cookie.get("cookie1"));
}

DEPRECATED

ALIAS format_rfc1123()

Deprecated alias for format_date().

COPYRIGHT

This document is licensed under the same conditions as Varnish itself.
See LICENSE for details.
SPDX-License-Identifier: BSD-2-Clause