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<?xml version="1.0" encoding="ISO-8859-1"?>
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<title>mod_session_dbd - Apache HTTP Server</title>
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<p class="apache">Apache HTTP Server Version 2.5</p>
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<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.5</a> > <a href="./">Modules</a></div>
<div id="page-content">
<div id="preamble"><h1>Apache Module mod_session_dbd</h1>
<div class="toplang">
<p><span>Available Languages: </span><a href="../en/mod/mod_session_dbd.html" title="English"> en </a></p>
</div>
<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>DBD/SQL based session support</td></tr>
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>session_dbd_module</td></tr>
<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_session_dbd.c</td></tr>
<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3 and later</td></tr></table>
<h3>Summary</h3>
<div class="warning"><h3>Warning</h3>
<p>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 account before enabling the session functionality on
your server.</p>
</div>
<p>This submodule of <code class="module"><a href="../mod/mod_session.html">mod_session</a></code> provides support for the
storage of user sessions within a SQL database using the
<code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> module.</p>
<p>Sessions can either be <strong>anonymous</strong>, where the session is
keyed by a unique UUID string stored on the browser in a cookie, or
<strong>per user</strong>, where the session is keyed against the userid of
the logged in user.</p>
<p>SQL based sessions are hidden from the browser, and so offer a measure of
privacy without the need for encryption.</p>
<p>Different webservers within a server farm may choose to share a database,
and so share sessions with one another.</p>
<p>For more details on the session interface, see the documentation for
the <code class="module"><a href="../mod/mod_session.html">mod_session</a></code> module.</p>
</div>
<div id="quickview"><h3 class="directives">Directives</h3>
<ul id="toc">
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdcookiename">SessionDBDCookieName</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdcookiename2">SessionDBDCookieName2</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdcookieremove">SessionDBDCookieRemove</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbddeletelabel">SessionDBDDeleteLabel</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdinsertlabel">SessionDBDInsertLabel</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdperuser">SessionDBDPerUser</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdselectlabel">SessionDBDSelectLabel</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdupdatelabel">SessionDBDUpdateLabel</a></li>
</ul>
<h3>Topics</h3>
<ul id="topics">
<li><img alt="" src="../images/down.gif" /> <a href="#dbdconfig">DBD Configuration</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#anonymous">Anonymous Sessions</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#peruser">Per User Sessions</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#housekeeping">Database Housekeeping</a></li>
</ul><h3>See also</h3>
<ul class="seealso">
<li><code class="module"><a href="../mod/mod_session.html">mod_session</a></code></li>
<li><code class="module"><a href="../mod/mod_session_crypto.html">mod_session_crypto</a></code></li>
<li><code class="module"><a href="../mod/mod_session_cookie.html">mod_session_cookie</a></code></li>
<li><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code></li>
</ul></div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="dbdconfig" id="dbdconfig">DBD Configuration</a></h2>
<p>Before the <code class="module"><a href="../mod/mod_session_dbd.html">mod_session_dbd</a></code> module can be configured to maintain a
session, the <code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> module must be configured to make the various database queries
available to the server.</p>
<p>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.</p>
<div class="example"><h3>Sample DBD configuration</h3><p><code>
DBDriver pgsql<br />
DBDParams "dbname=apachesession user=apache password=xxxxx host=localhost"<br />
DBDPrepareSQL "delete from session where key = %s" deletesession<br />
DBDPrepareSQL "update session set value = %s, expiry = %lld where key = %s" updatesession<br />
DBDPrepareSQL "insert into session (value, expiry, key) values (%s, %lld, %s)" insertsession<br />
DBDPrepareSQL "select value from session where key = %s and (expiry = 0 or expiry > %lld)" selectsession<br />
DBDPrepareSQL "delete from session where expiry != 0 and expiry < %lld" cleansession<br />
</code></p></div>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="anonymous" id="anonymous">Anonymous Sessions</a></h2>
<p>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.</p>
<p>To create a simple anonymous session and store it in a postgres database
table called <var>apachesession</var>, and save the session ID in a cookie
called <var>session</var>, configure the session as follows:</p>
<div class="example"><h3>SQL based anonymous session</h3><p><code>
Session On<br />
SessionDBDCookieName session path=/<br />
</code></p></div>
<p>For more examples on how the session can be configured to be read
from and written to by a CGI application, see the
<code class="module"><a href="../mod/mod_session.html">mod_session</a></code> examples section.</p>
<p>For documentation on how the session can be used to store username
and password details, see the <code class="module"><a href="../mod/mod_auth_form.html">mod_auth_form</a></code> module.</p>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="peruser" id="peruser">Per User Sessions</a></h2>
<p>Per user sessions are keyed against the username of a successfully
authenticated user. It offers the most privacy, as no external handle
to the session exists outside of the authenticated realm.</p>
<p>Per user 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 user sessions cannot be used to store
authentication credentials from a module like
<code class="module"><a href="../mod/mod_auth_form.html">mod_auth_form</a></code>.</p>
<p>To create a simple per user session and store it in a postgres database
table called <var>apachesession</var>, and with the session keyed to the
userid, configure the session as follows:</p>
<div class="example"><h3>SQL based per user session</h3><p><code>
Session On<br />
SessionDBDPerUser On<br />
</code></p></div>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="housekeeping" id="housekeeping">Database Housekeeping</a></h2>
<p>Over the course of time, the database can be expected to start accumulating
expired sessions. At this point, the <code class="module"><a href="../mod/mod_session_dbd.html">mod_session_dbd</a></code> module
is not yet able to handle session expiry automatically.</p>
<div class="warning"><h3>Warning</h3>
<p>The administrator will need to set up an external process via cron to clean
out expired sessions.</p>
</div>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDCookieName" id="SessionDBDCookieName">SessionDBDCookieName</a> <a name="sessiondbdcookiename" id="sessiondbdcookiename">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name and attributes for the RFC2109 cookie storing the session ID</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDCookieName <var>name</var> <var>attributes</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>none</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDCookieName</code> 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 <code>Set-Cookie</code> HTTP header.
</p>
<p>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.
</p>
<div class="example"><h3>Cookie with attributes</h3><p><code>
Session On<br />
SessionDBDCookieName session path=/private;domain=example.com;httponly;secure;version=1;<br />
</code></p></div>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDCookieName2" id="SessionDBDCookieName2">SessionDBDCookieName2</a> <a name="sessiondbdcookiename2" id="sessiondbdcookiename2">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Name and attributes for the RFC2965 cookie storing the session ID</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDCookieName2 <var>name</var> <var>attributes</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>none</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDCookieName2</code> 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 <code>Set-Cookie2</code> HTTP header.
</p>
<p>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.
</p>
<div class="example"><h3>Cookie2 with attributes</h3><p><code>
Session On<br />
SessionDBDCookieName2 session path=/private;domain=example.com;httponly;secure;version=1;<br />
</code></p></div>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDCookieRemove" id="SessionDBDCookieRemove">SessionDBDCookieRemove</a> <a name="sessiondbdcookieremove" id="sessiondbdcookieremove">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Control for whether session ID cookies should be removed from incoming HTTP headers</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDCookieRemove On|Off</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDCookieRemove On</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDCookieRemove</code> flag controls whether the cookies
containing the session ID will be removed from the headers during request processing.</p>
<p>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.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDDeleteLabel" id="SessionDBDDeleteLabel">SessionDBDDeleteLabel</a> <a name="sessiondbddeletelabel" id="sessiondbddeletelabel">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The SQL query to use to remove sessions from the database</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDDeleteLabel <var>label</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDDeleteLabel deletesession</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDDeleteLabel</code> 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 <code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDInsertLabel" id="SessionDBDInsertLabel">SessionDBDInsertLabel</a> <a name="sessiondbdinsertlabel" id="sessiondbdinsertlabel">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The SQL query to use to insert sessions into the database</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDInsertLabel <var>label</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDInsertLabel insertsession</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDInsertLabel</code> directive sets the default insert
query label to be used to load in a session. This label must have been previously defined using the
<code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
<p>If an attempt to update the session affects no rows, this query will be called to insert the
session into the database.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDPerUser" id="SessionDBDPerUser">SessionDBDPerUser</a> <a name="sessiondbdperuser" id="sessiondbdperuser">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable a per user session</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDPerUser On|Off</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDPerUser Off</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDPerUser</code> flag enables a per user session keyed
against the user's login name. If the user is not logged in, this directive will be
ignored.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDSelectLabel" id="SessionDBDSelectLabel">SessionDBDSelectLabel</a> <a name="sessiondbdselectlabel" id="sessiondbdselectlabel">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The SQL query to use to select sessions from the database</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDSelectLabel <var>label</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDSelectLabel selectsession</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDSelectLabel</code> directive sets the default select
query label to be used to load in a session. This label must have been previously defined using the
<code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="SessionDBDUpdateLabel" id="SessionDBDUpdateLabel">SessionDBDUpdateLabel</a> <a name="sessiondbdupdatelabel" id="sessiondbdupdatelabel">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The SQL query to use to update existing sessions in the database</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDUpdateLabel <var>label</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDUpdateLabel updatesession</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
</table>
<p>The <code class="directive">SessionDBDUpdateLabel</code> directive sets the default update
query label to be used to load in a session. This label must have been previously defined using the
<code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
<p>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 supports InsertOrUpdate,
override this query to perform the update in one query instead of two.</p>
</div>
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