Database Reference
In-Depth Information
Session expiration
The Apache::Session module requires only the
id
and
a_session
columns in the
perl_session
table. The module makes no provision for timing out or expiring ses‐
sions, but doesn't restrict you from adding other columns, so you can implement those
capabilities yourself. Add a
TIMESTAMP
column to the table to store the time of each
session's last modification (MySQL updates it automatically whenever a session record
is changed):
ALTER
TABLE
perl_session
ADD
update_time
TIMESTAMP
NOT
NULL
,
ADD
INDEX
(
update_time
);
To expire sessions, run a statement periodically that sweeps the table and removes old
rows. The following statement uses an expiration time of four hours:
DELETE
FROM
perl_session
WHERE
update_time
<
NOW
()
-
INTERVAL
4
HOUR
;
The
ALTER
TABLE
statement indexes
update_time
to make the
DELETE
operation faster.
To expire rows automatically, create a scheduled event (see
Recipe 9.8
). This event runs
every four hours:
CREATE
EVENT
expire_perl_session
ON
SCHEDULE
EVERY
4
HOUR
DO
DELETE
FROM
perl_session
WHERE
update_time
<
NOW
()
-
INTERVAL
4
HOUR
;
21.2. Using MySQL-Based Storage in Ruby Applications
Problem
You want to use session storage for Ruby scripts.
Solution
Use the
CGI::Session
class interface. By default, it uses temporary files for backing
store, but you can configure it to use MySQL instead.
Discussion
The
CGI::Session
class manages session storage. It identifies sessions using cookies,
which it adds transparently to the responses sent to the client.
CGI::Session
permits
use of alternative storage-management classes in place of the default manager that uses
temporary files. We'll use the
mysql-session
package, which is based on the Ruby DBI
interface and stores session records using MySQL.
mysql-session
is available from the
MySQL Cookbook
companion website (see the
Preface
).
To use
mysql-session
in a script, include these modules:
