Apache HTTP Server Version 2.4
Available Languages: fr
Description: | DBD/SQL based session |
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Status: | Extension |
Module Identifier: | session_dbd_module |
Source File: | mod_session_dbd.c |
Compatibility: | Available in Apache 2.3 and later |
The session modules make use of HTTP cookies, and as such can fall victim to Cross Site Scripting attacks, or expose potentially private information to clients. Please ensure that the relevant risks have been taken into before enabling the session functionality on your server.
This submodule of mod_dbd
module.
Sessions can either be anonymous, where the session is keyed by a unique UUID string stored on the browser in a cookie, or per , where the session is keyed against the id of the logged in .
SQL based sessions are hidden from the browser, and so offer a measure of privacy without the need for encryption.
Different webservers within a server farm may choose to share a database, and so share sessions with one another.
For more details on the session interface, see the documentation for the mod_session
module.
Before the mod_dbd
module must be configured to make the various database queries available to the server.
There are four queries required to keep a session maintained, to select an existing session, to update an existing session, to insert a new session, and to delete an expired or empty session. These queries are configured as per the example below.
DBDriver pgsql DBDParams "dbname=apachesession =apache =xxxxx host=localhost" DBDPrepareSQL "delete from session where key = %s" deletesession DBDPrepareSQL "update session set value = %s, expiry = %lld, key = %s where key = %s" updatesession DBDPrepareSQL "insert into session (value, expiry, key) values (%s, %lld, %s)" insertsession DBDPrepareSQL "select value from session where key = %s and (expiry = 0 or expiry > %lld)" selectsession DBDPrepareSQL "delete from session where expiry != 0 and expiry < %lld" cleansession
Anonymous sessions are keyed against a unique UUID, and stored on the browser within an HTTP cookie. This method is similar to that used by most application servers to store session information.
To create a simple anonymous session and store it in a postgres database table called apachesession, and save the session ID in a cookie called session, configure the session as follows:
Session On SessionDBDCookieName session path=/
For more examples on how the session can be configured to be read from and written to by a CGI application, see the mod_session
examples section.
For documentation on how the session can be used to store name and details, see the mod_auth_form
module.
Per sessions are keyed against the name of a successfully authenticated . It offers the most privacy, as no external handle to the session exists outside of the authenticated realm.
Per sessions work within a correctly configured authenticated environment, be that using basic authentication, digest authentication or SSL client certificates. Due to the limitations of who came first, the chicken or the egg, per sessions cannot be used to store authentication credentials from a module like mod_auth_form
.
To create a simple per session and store it in a postgres database table called apachesession, and with the session keyed to the id, configure the session as follows:
Session On SessionDBDPer On
Over the course of time, the database can be expected to start accumulating expired sessions. At this point, the mod_session_dbd
module is not yet able to handle session expiry automatically.
The will need to set up an external process via cron to clean out expired sessions.
Description: | Name and attributes for the RFC2109 cookie storing the session ID |
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Syntax: | SessionDBDCookieName name attributes |
Default: | none |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDCookieName
directive specifies the name and optional attributes of an RFC2109 compliant cookie inside which the session ID will be stored. RFC2109 cookies are set using the Set-Cookie
HTTP header.
An optional list of cookie attributes can be specified, as per the example below. These attributes are inserted into the cookie as is, and are not interpreted by Apache. Ensure that your attributes are defined correctly as per the cookie specification.
Session On SessionDBDCookieName session path=/private;domain=example.com;httponly;secure;version=1;
Description: | Name and attributes for the RFC2965 cookie storing the session ID |
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Syntax: | SessionDBDCookieName2 name attributes |
Default: | none |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDCookieName2
directive specifies the name and optional attributes of an RFC2965 compliant cookie inside which the session ID will be stored. RFC2965 cookies are set using the Set-Cookie2
HTTP header.
An optional list of cookie attributes can be specified, as per the example below. These attributes are inserted into the cookie as is, and are not interpreted by Apache. Ensure that your attributes are defined correctly as per the cookie specification.
Session On SessionDBDCookieName2 session path=/private;domain=example.com;httponly;secure;version=1;
Description: | Control for whether session ID cookies should be removed from incoming HTTP headers |
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Syntax: | SessionDBDCookieRemove On|Off |
Default: | SessionDBDCookieRemove On |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDCookieRemove
flag controls whether the cookies containing the session ID will be removed from the headers during request processing.
In a reverse proxy situation where the Apache server acts as a server frontend for a backend origin server, revealing the contents of the session ID cookie to the backend could be a potential privacy violation. When set to on, the session ID cookie will be removed from the incoming HTTP headers.
Description: | The SQL query to use to remove sessions from the database |
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Syntax: | SessionDBDDeleteLabel label |
Default: | SessionDBDDeleteLabel deletesession |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDDeleteLabel
directive sets the default delete query label to be used to delete an expired or empty session. This label must have been previously defined using the DBDPrepareSQL
directive.
Description: | The SQL query to use to insert sessions into the database |
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Syntax: | SessionDBDInsertLabel label |
Default: | SessionDBDInsertLabel insertsession |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDInsertLabel
directive sets the default insert query label to be used to load in a session. This label must have been previously defined using the DBDPrepareSQL
directive.
If an attempt to update the session affects no rows, this query will be called to insert the session into the database.
Description: | Enable a per session |
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Syntax: | SessionDBDPer On|Off |
Default: | SessionDBDPer Off |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDPer
flag enables a per session keyed against the 's name. If the is not logged in, this directive will be ignored.
Description: | The SQL query to use to select sessions from the database |
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Syntax: | SessionDBDSelectLabel label |
Default: | SessionDBDSelectLabel selectsession |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDSelectLabel
directive sets the default select query label to be used to load in a session. This label must have been previously defined using the DBDPrepareSQL
directive.
Description: | The SQL query to use to update existing sessions in the database |
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Syntax: | SessionDBDUpdateLabel label |
Default: | SessionDBDUpdateLabel updatesession |
Context: | server config, virtual host, directory, .htaccess |
Status: | Extension |
Module: | mod_session_dbd |
The SessionDBDUpdateLabel
directive sets the default update query label to be used to load in a session. This label must have been previously defined using the DBDPrepareSQL
directive.
If an attempt to update the session affects no rows, the insert query will be called to insert the session into the database. If the database s InsertOrUpdate, override this query to perform the update in one query instead of two.
Available Languages: fr