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16 <p class="apache">Apache HTTP Server Version 2.3</p>
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21 <div id="page-content">
22 <div id="preamble"><h1>Apache Module mod_session_dbd</h1>
24 <p><span>Available Languages: </span><a href="../en/mod/mod_session_dbd.html" title="English"> en </a></p>
26 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>DBD/SQL based session support</td></tr>
27 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
28 <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>session_dbd_module</td></tr>
29 <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_session_dbd.c</td></tr></table>
32 <div class="warning"><h3>Warning</h3>
33 <p>The session modules make use of HTTP cookies, and as such can fall
34 victim to Cross Site Scripting attacks, or expose potentially private
35 information to clients. Please ensure that the relevant risks have
36 been taken into account before enabling the session functionality on
40 <p>This submodule of <code class="module"><a href="../mod/mod_session.html">mod_session</a></code> provides support for the
41 storage of user sessions within a SQL database using the
42 <code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code> module.</p>
44 <p>Sessions can either be <strong>anonymous</strong>, where the session is
45 keyed by a unique UUID string stored on the browser in a cookie, or
46 <strong>per user</strong>, where the session is keyed against the userid of
47 the logged in user.</p>
49 <p>SQL based sessions are hidden from the browser, and so offer a measure of
50 privacy without the need for encryption.</p>
52 <p>Different webservers within a server farm may choose to share a database,
53 and so share sessions with one another.</p>
55 <p>For more details on the session interface, see the documentation for
56 the <code class="module"><a href="../mod/mod_session.html">mod_session</a></code> module.</p>
59 <div id="quickview"><h3 class="directives">Directives</h3>
61 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdcookiename">SessionDBDCookieName</a></li>
62 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdcookiename2">SessionDBDCookieName2</a></li>
63 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdcookieremove">SessionDBDCookieRemove</a></li>
64 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbddeletelabel">SessionDBDDeleteLabel</a></li>
65 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdinsertlabel">SessionDBDInsertLabel</a></li>
66 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdperuser">SessionDBDPerUser</a></li>
67 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdselectlabel">SessionDBDSelectLabel</a></li>
68 <li><img alt="" src="../images/down.gif" /> <a href="#sessiondbdupdatelabel">SessionDBDUpdateLabel</a></li>
72 <li><img alt="" src="../images/down.gif" /> <a href="#dbdconfig">DBD Configuration</a></li>
73 <li><img alt="" src="../images/down.gif" /> <a href="#anonymous">Anonymous Sessions</a></li>
74 <li><img alt="" src="../images/down.gif" /> <a href="#peruser">Per User Sessions</a></li>
75 <li><img alt="" src="../images/down.gif" /> <a href="#housekeeping">Database Housekeeping</a></li>
76 </ul><h3>See also</h3>
78 <li><code class="module"><a href="../mod/mod_session.html">mod_session</a></code></li>
79 <li><code class="module"><a href="../mod/mod_session_crypto.html">mod_session_crypto</a></code></li>
80 <li><code class="module"><a href="../mod/mod_session_cookie.html">mod_session_cookie</a></code></li>
81 <li><code class="module"><a href="../mod/mod_dbd.html">mod_dbd</a></code></li>
83 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
85 <h2><a name="dbdconfig" id="dbdconfig">DBD Configuration</a></h2>
87 <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
88 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
89 available to the server.</p>
91 <p>There are four queries required to keep a session maintained, to select an existing session,
92 to update an existing session, to insert a new session, and to delete an expired or empty
93 session. These queries are configured as per the example below.</p>
95 <div class="example"><h3>Sample DBD configuration</h3><p><code>
97 DBDParams "dbname=apachesession user=apache password=xxxxx host=localhost"<br />
98 DBDPrepareSQL "delete from session where key = %s" deletesession<br />
99 DBDPrepareSQL "update session set value = %s, expiry = %lld where key = %s" updatesession<br />
100 DBDPrepareSQL "insert into session (value, expiry, key) values (%s, %lld, %s)" insertsession<br />
101 DBDPrepareSQL "select value from session where key = %s and (expiry = 0 or expiry > %lld)" selectsession<br />
102 DBDPrepareSQL "delete from session where expiry != 0 and expiry < %lld" cleansession<br />
105 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
106 <div class="section">
107 <h2><a name="anonymous" id="anonymous">Anonymous Sessions</a></h2>
109 <p>Anonymous sessions are keyed against a unique UUID, and stored on the
110 browser within an HTTP cookie. This method is similar to that used by most
111 application servers to store session information.</p>
113 <p>To create a simple anonymous session and store it in a postgres database
114 table called <var>apachesession</var>, and save the session ID in a cookie
115 called <var>session</var>, configure the session as follows:</p>
117 <div class="example"><h3>SQL based anonymous session</h3><p><code>
119 SessionDBDCookieName session path=/<br />
122 <p>For more examples on how the session can be configured to be read
123 from and written to by a CGI application, see the
124 <code class="module"><a href="../mod/mod_session.html">mod_session</a></code> examples section.</p>
126 <p>For documentation on how the session can be used to store username
127 and password details, see the <code class="module"><a href="../mod/mod_auth_form.html">mod_auth_form</a></code> module.</p>
129 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
130 <div class="section">
131 <h2><a name="peruser" id="peruser">Per User Sessions</a></h2>
133 <p>Per user sessions are keyed against the username of a successfully
134 authenticated user. It offers the most privacy, as no external handle
135 to the session exists outside of the authenticated realm.</p>
137 <p>Per user sessions work within a correctly configured authenticated
138 environment, be that using basic authentication, digest authentication
139 or SSL client certificates. Due to the limitations of who came first,
140 the chicken or the egg, per user sessions cannot be used to store
141 authentication credentials from a module like
142 <code class="module"><a href="../mod/mod_auth_form.html">mod_auth_form</a></code>.</p>
144 <p>To create a simple per user session and store it in a postgres database
145 table called <var>apachesession</var>, and with the session keyed to the
146 userid, configure the session as follows:</p>
148 <div class="example"><h3>SQL based per user session</h3><p><code>
150 SessionDBDPerUser On<br />
153 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
154 <div class="section">
155 <h2><a name="housekeeping" id="housekeeping">Database Housekeeping</a></h2>
156 <p>Over the course of time, the database can be expected to start accumulating
157 expired sessions. At this point, the <code class="module"><a href="../mod/mod_session_dbd.html">mod_session_dbd</a></code> module
158 is not yet able to handle session expiry automatically.</p>
160 <div class="warning"><h3>Warning</h3>
161 <p>The administrator will need to set up an external process via cron to clean
162 out expired sessions.</p>
166 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
167 <div class="directive-section"><h2><a name="SessionDBDCookieName" id="SessionDBDCookieName">SessionDBDCookieName</a> <a name="sessiondbdcookiename" id="sessiondbdcookiename">Directive</a></h2>
168 <table class="directive">
169 <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>
170 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDCookieName <var>name</var> <var>attributes</var></code></td></tr>
171 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>none</code></td></tr>
172 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
173 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
174 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
175 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
177 <p>The <code class="directive">SessionDBDCookieName</code> directive specifies the name and
178 optional attributes of an RFC2109 compliant cookie inside which the session ID will
179 be stored. RFC2109 cookies are set using the <code>Set-Cookie</code> HTTP header.
182 <p>An optional list of cookie attributes can be specified, as per the example below.
183 These attributes are inserted into the cookie as is, and are not interpreted by
184 Apache. Ensure that your attributes are defined correctly as per the cookie specification.
187 <div class="example"><h3>Cookie with attributes</h3><p><code>
189 SessionDBDCookieName session path=/private;domain=example.com;httponly;secure;version=1;<br />
194 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
195 <div class="directive-section"><h2><a name="SessionDBDCookieName2" id="SessionDBDCookieName2">SessionDBDCookieName2</a> <a name="sessiondbdcookiename2" id="sessiondbdcookiename2">Directive</a></h2>
196 <table class="directive">
197 <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>
198 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDCookieName2 <var>name</var> <var>attributes</var></code></td></tr>
199 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>none</code></td></tr>
200 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
201 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
202 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
203 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
205 <p>The <code class="directive">SessionDBDCookieName2</code> directive specifies the name and
206 optional attributes of an RFC2965 compliant cookie inside which the session ID will
207 be stored. RFC2965 cookies are set using the <code>Set-Cookie2</code> HTTP header.
210 <p>An optional list of cookie attributes can be specified, as per the example below.
211 These attributes are inserted into the cookie as is, and are not interpreted by
212 Apache. Ensure that your attributes are defined correctly as per the cookie specification.
215 <div class="example"><h3>Cookie2 with attributes</h3><p><code>
217 SessionDBDCookieName2 session path=/private;domain=example.com;httponly;secure;version=1;<br />
222 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
223 <div class="directive-section"><h2><a name="SessionDBDCookieRemove" id="SessionDBDCookieRemove">SessionDBDCookieRemove</a> <a name="sessiondbdcookieremove" id="sessiondbdcookieremove">Directive</a></h2>
224 <table class="directive">
225 <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>
226 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDCookieRemove On|Off</code></td></tr>
227 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDCookieRemove On</code></td></tr>
228 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
229 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
230 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
231 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
233 <p>The <code class="directive">SessionDBDCookieRemove</code> flag controls whether the cookies
234 containing the session ID will be removed from the headers during request processing.</p>
236 <p>In a reverse proxy situation where the Apache server acts as a server frontend for
237 a backend origin server, revealing the contents of the session ID cookie to the backend
238 could be a potential privacy violation. When set to on, the session ID cookie will be
239 removed from the incoming HTTP headers.</p>
243 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
244 <div class="directive-section"><h2><a name="SessionDBDDeleteLabel" id="SessionDBDDeleteLabel">SessionDBDDeleteLabel</a> <a name="sessiondbddeletelabel" id="sessiondbddeletelabel">Directive</a></h2>
245 <table class="directive">
246 <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>
247 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDDeleteLabel <var>label</var></code></td></tr>
248 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDDeleteLabel deletesession</code></td></tr>
249 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
250 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
251 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
252 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
254 <p>The <code class="directive">SessionDBDDeleteLabel</code> directive sets the default delete
255 query label to be used to delete an expired or empty session. This label must have been previously
256 defined using the <code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
260 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
261 <div class="directive-section"><h2><a name="SessionDBDInsertLabel" id="SessionDBDInsertLabel">SessionDBDInsertLabel</a> <a name="sessiondbdinsertlabel" id="sessiondbdinsertlabel">Directive</a></h2>
262 <table class="directive">
263 <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>
264 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDInsertLabel <var>label</var></code></td></tr>
265 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDInsertLabel insertsession</code></td></tr>
266 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
267 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
268 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
269 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
271 <p>The <code class="directive">SessionDBDInsertLabel</code> directive sets the default insert
272 query label to be used to load in a session. This label must have been previously defined using the
273 <code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
275 <p>If an attempt to update the session affects no rows, this query will be called to insert the
276 session into the database.</p>
280 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
281 <div class="directive-section"><h2><a name="SessionDBDPerUser" id="SessionDBDPerUser">SessionDBDPerUser</a> <a name="sessiondbdperuser" id="sessiondbdperuser">Directive</a></h2>
282 <table class="directive">
283 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable a per user session</td></tr>
284 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDPerUser On|Off</code></td></tr>
285 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDPerUser Off</code></td></tr>
286 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
287 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
288 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
289 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
291 <p>The <code class="directive">SessionDBDPerUser</code> flag enables a per user session keyed
292 against the user's login name. If the user is not logged in, this directive will be
297 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
298 <div class="directive-section"><h2><a name="SessionDBDSelectLabel" id="SessionDBDSelectLabel">SessionDBDSelectLabel</a> <a name="sessiondbdselectlabel" id="sessiondbdselectlabel">Directive</a></h2>
299 <table class="directive">
300 <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>
301 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDSelectLabel <var>label</var></code></td></tr>
302 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDSelectLabel selectsession</code></td></tr>
303 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
304 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
305 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
306 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
308 <p>The <code class="directive">SessionDBDSelectLabel</code> directive sets the default select
309 query label to be used to load in a session. This label must have been previously defined using the
310 <code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
314 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
315 <div class="directive-section"><h2><a name="SessionDBDUpdateLabel" id="SessionDBDUpdateLabel">SessionDBDUpdateLabel</a> <a name="sessiondbdupdatelabel" id="sessiondbdupdatelabel">Directive</a></h2>
316 <table class="directive">
317 <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>
318 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SessionDBDUpdateLabel <var>label</var></code></td></tr>
319 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SessionDBDUpdateLabel updatesession</code></td></tr>
320 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
321 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
322 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_session_dbd</td></tr>
323 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.3.0 and later</td></tr>
325 <p>The <code class="directive">SessionDBDUpdateLabel</code> directive sets the default update
326 query label to be used to load in a session. This label must have been previously defined using the
327 <code class="directive"><a href="../mod/mod_dbd.html#dbdpreparesql">DBDPrepareSQL</a></code> directive.</p>
329 <p>If an attempt to update the session affects no rows, the insert query will be
330 called to insert the session into the database. If the database supports InsertOrUpdate,
331 override this query to perform the update in one query instead of two.</p>
336 <div class="bottomlang">
337 <p><span>Available Languages: </span><a href="../en/mod/mod_session_dbd.html" title="English"> en </a></p>
338 </div><div id="footer">
339 <p class="apache">Copyright 2008 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
340 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div>