<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.43 $ -->
<section id="session.configuration">
 &reftitle.runtime;
 &extension.runtime;
 <para>
 <table>
  <title>Session configuration options</title>
  <tgroup cols="4">
   <thead>
    <row>
     <entry>Name</entry>
     <entry>Default</entry>
     <entry>Changeable</entry>
     <entry>Changelog</entry>
    </row>
   </thead>
   <tbody>
    <row>
     <entry>session.save_path</entry>
     <entry>""</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.name</entry>
     <entry>"PHPSESSID"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.save_handler</entry>
     <entry>"files"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.auto_start</entry>
     <entry>"0"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.gc_probability</entry>
     <entry>"1"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.gc_divisor</entry>
     <entry>"100"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 4.3.2.</entry>
    </row>
    <row>
     <entry>session.gc_maxlifetime</entry>
     <entry>"1440"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.serialize_handler</entry>
     <entry>"php"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.cookie_lifetime</entry>
     <entry>"0"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.cookie_path</entry>
     <entry>"/"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.cookie_domain</entry>
     <entry>""</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.cookie_secure</entry>
     <entry>""</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 4.0.4.</entry>
    </row>
    <row>
     <entry>session.cookie_httponly</entry>
     <entry>""</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 5.2.0.</entry>
    </row>
    <row>
     <entry>session.use_cookies</entry>
     <entry>"1"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.use_only_cookies</entry>
     <entry>"1"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 4.3.0.</entry>
    </row>
    <row>
     <entry>session.referer_check</entry>
     <entry>""</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.entropy_file</entry>
     <entry>""</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.entropy_length</entry>
     <entry>"0"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.cache_limiter</entry>
     <entry>"nocache"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.cache_expire</entry>
     <entry>"180"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry></entry>
    </row>
    <row>
     <entry>session.use_trans_sid</entry>
     <entry>"0"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>PHP_INI_ALL in PHP &lt;= 4.2.3. PHP_INI_PERDIR in PHP &lt; 5. Available since PHP 4.0.3.</entry>
    </row>
    <row>
     <entry>session.bug_compat_42</entry>
     <entry>"1"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 4.3.0.</entry>
    </row>
    <row>
     <entry>session.bug_compat_warn</entry>
     <entry>"1"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 4.3.0.</entry>
    </row>
    <row>
     <entry>session.hash_function</entry>
     <entry>"0"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 5.0.0.</entry>
    </row>
    <row>
     <entry>session.hash_bits_per_character</entry>
     <entry>"4"</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 5.0.0.</entry>
    </row>
    <row>
     <entry>url_rewriter.tags</entry>
     <entry>"a=href,area=href,frame=src,form=,fieldset="</entry>
     <entry>PHP_INI_ALL</entry>
     <entry>Available since PHP 4.0.4.</entry>
    </row>
   </tbody>
  </tgroup>
 </table>
 &ini.php.constants;
 </para>
 <para>
  The session management system supports a number of configuration
  options which you can place in your &php.ini; file. We will give a
  short overview.
 <variablelist>

  <varlistentry id="ini.session.save-handler">
   <term>
    <parameter>session.save_handler</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.save_handler</literal> defines the name of the
     handler which is used for storing and retrieving data
     associated with a session. Defaults to
     <literal>files</literal>. See also
     <function>session_set_save_handler</function>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.save-path">
   <term>
    <parameter>session.save_path</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.save_path</literal> defines the argument which
     is passed to the save handler. If you choose the default files
     handler, this is the path where the files are created.  Defaults to
     <literal>/tmp</literal>.  See also
     <function>session_save_path</function>. 
    </simpara>
    <para>
     There is an optional N argument to this directive that determines 
     the number of directory levels your session files will be spread
     around in.  For example, setting to <literal>'5;/tmp'</literal>
     may end up creating a session file and location like
     <literal>/tmp/4/b/1/e/3/sess_4b1e384ad74619bd212e236e52a5a174If
     </literal>.  In order to use N you must create all of these
     directories before use.  A small shell script exists in
     <filename>ext/session</filename> to do this, it's called
     <filename>mod_files.sh</filename>.  Also note that if N is
     used and greater than 0 then automatic garbage collection will
     not be performed, see a copy of &php.ini; for further
     information.  Also, if you use N, be sure to surround
     <literal>session.save_path</literal> in  
     "quotes" because the separator (<literal>;</literal>) is
     also used for comments in &php.ini;.
    </para>
    <warning>
     <para>
      If you leave this set to a world-readable directory, such as
      <filename>/tmp</filename> (the default), other users on the
      server may be able to hijack sessions by getting the list of
      files in that directory.
     </para>
    </warning>
    <note>
     <simpara>
      Prior to PHP 4.3.6, Windows users had to change this variable in order
      to use PHP's session functions. A valid path must be specified, e.g.:
      <filename>c:/temp</filename>.
     </simpara>
    </note>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.name">
   <term>
    <parameter>session.name</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.name</literal> specifies the name of the
     session which is used as cookie name. It should only contain
     alphanumeric characters. Defaults to <literal>PHPSESSID</literal>.
     See also <function>session_name</function>.
    </simpara>
   </listitem>
  </varlistentry>
  
  <varlistentry id="ini.session.auto-start">
   <term>
    <parameter>session.auto_start</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.auto_start</literal> specifies whether the
     session module starts a session automatically on request
     startup. Defaults to <literal>0</literal> (disabled).
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.serialize-handler">
   <term>
    <parameter>session.serialize_handler</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.serialize_handler</literal> defines the name
     of the handler which is used to serialize/deserialize
     data. Currently, a PHP internal format (name
     <literal>php</literal>) and WDDX are supported (name
     <literal>wddx</literal>). WDDX is only available, if PHP is
     compiled with <link linkend="ref.wddx">WDDX
     support</link>. Defaults to <literal>php</literal>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.gc-probability">
   <term>
    <parameter>session.gc_probability</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.gc_probability</literal> in conjunction with
     <literal>session.gc_divisor</literal> is used to manage probability
     that the gc (garbage collection) routine is started.
     Defaults to <literal>1</literal>. See <link
     linkend="ini.session.gc-divisor">session.gc_divisor</link> for details.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.gc-divisor">
   <term>
    <parameter>session.gc_divisor</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.gc_divisor</literal> coupled with 
     <literal>session.gc_probability</literal> defines the probability 
     that the gc (garbage collection) process is started on every session 
     initialization.
     The probability is calculated by using gc_probability/gc_divisor,
     e.g. 1/100 means there is a 1% chance that the GC process starts
     on each request.
     <literal>session.gc_divisor</literal> defaults to <literal>100</literal>.
    </simpara>
   </listitem>
  </varlistentry>
  
  <varlistentry id="ini.session.gc-maxlifetime">
   <term>
    <parameter>session.gc_maxlifetime</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.gc_maxlifetime</literal> specifies the number
     of seconds after which data will be seen as 'garbage' and
     cleaned up. Garbage collection occurs during session start.
    </simpara>
    <note>
     <para>
      If different scripts have different values of
      <literal>session.gc_maxlifetime</literal> but share the same place for
      storing the session data then the script with the minimum value will be
      cleaning the data. In this case, use this directive together with <link
      linkend="ini.session.save-path">session.save_path</link>.
     </para>
    </note>
    <note>
     <simpara>If you are using the default file-based session handler, your
     filesystem must keep track of access times (atime). Windows FAT does
     not so you will have to come up with another way to handle garbage
     collecting your session if you are stuck with a FAT filesystem or any
     other filesystem where atime tracking is not available.
     Since PHP 4.2.3 it has used mtime (modified date) instead of atime. So, you
     won't have problems with filesystems where atime tracking is not available.
     </simpara>
    </note>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.referer-check">
   <term>
    <parameter>session.referer_check</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.referer_check</literal> contains the
     substring you want to check each HTTP Referer for. If the
     Referer was sent by the client and the substring was not
     found, the embedded session id will be marked as invalid.
     Defaults to the empty string.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.entropy-file">
   <term>
    <parameter>session.entropy_file</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.entropy_file</literal> gives a path to an
     external resource (file) which will be used as an additional
     entropy source in the session id creation process. Examples are
     <literal>/dev/random</literal> or <literal>/dev/urandom</literal>
     which are available on many Unix systems.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.entropy-length">
   <term>
    <parameter>session.entropy_length</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.entropy_length</literal> specifies the number
     of bytes which will be read from the file specified
     above. Defaults to <literal>0</literal> (disabled).
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.use-cookies">
   <term>
    <parameter>session.use_cookies</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.use_cookies</literal> specifies whether the
     module will use cookies to store the session id on the client
     side. Defaults to <literal>1</literal> (enabled).
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.use-only-cookies">
   <term>
    <parameter>session.use_only_cookies</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.use_only_cookies</literal> specifies whether
     the module will <emphasis role="strong">only</emphasis> use
     cookies to store the session id on the client side.
     Enabling this setting prevents attacks involved passing session
     ids in URLs. This setting was added in PHP 4.3.0.
    </simpara>
   </listitem>
  </varlistentry>


  <varlistentry id="ini.session.cookie-lifetime">
   <term>
    <parameter>session.cookie_lifetime</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.cookie_lifetime</literal> specifies the lifetime of
     the cookie in seconds which is sent to the browser. The value 0
     means "until the browser is closed." Defaults to
     <literal>0</literal>. See also
     <function>session_get_cookie_params</function> and
     <function>session_set_cookie_params</function>.
     Since the cookie is returned by the browser, it is not prolonged to
     suffice the lifetime. It must be sent manually by
     <function>setcookie</function>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.cookie-path">
   <term>
    <parameter>session.cookie_path</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.cookie_path</literal> specifies path to set
     in session_cookie. Defaults to <literal>/</literal>. See also
     <function>session_get_cookie_params</function> and
     <function>session_set_cookie_params</function>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.cookie-domain">
   <term>
    <parameter>session.cookie_domain</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.cookie_domain</literal> specifies the domain to
     set in session_cookie. Default is none at all meaning the host name of
     the server which generated the cookie according to cookies specification.
     See also <function>session_get_cookie_params</function> and
     <function>session_set_cookie_params</function>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.cookie-secure">
   <term>
    <parameter>session.cookie_secure</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.cookie_secure</literal> specifies whether
     cookies should only be sent over secure connections. Defaults to
     <literal>off</literal>.
     This setting was added in PHP 4.0.4. See also
     <function>session_get_cookie_params</function> and
     <function>session_set_cookie_params</function>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.cookie-httponly">
   <term>
    <parameter>session.cookie_httponly</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     Marks the cookie as accessible only through the HTTP protocol. This means
     that the cookie won't be accessible by scripting languages, such as
     JavaScript. This setting can effectively help to reduce identity theft
     through XSS attacks (although it is not supported by all browsers).
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.cache-limiter">
   <term>
    <parameter>session.cache_limiter</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.cache_limiter</literal> specifies cache
     control method to use for session pages
     (none/nocache/private/private_no_expire/public). Defaults to
     <literal>nocache</literal>. See also
     <function>session_cache_limiter</function>.
    </simpara>
   </listitem>
  </varlistentry>


  <varlistentry id="ini.session.cache-expire">
   <term>
    <parameter>session.cache_expire</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.cache_expire</literal> specifies time-to-live
     for cached session pages in minutes, this has no effect for
     nocache limiter. Defaults to <literal>180</literal>. See also
     <function>session_cache_expire</function>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.use-trans-sid">
   <term>
    <parameter>session.use_trans_sid</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.use_trans_sid</literal> whether transparent
     sid support is enabled or not. Defaults to
     <literal>0</literal> (disabled).
    </simpara>
    <note>
     <simpara>
      For PHP 4.1.2 or less, it is enabled by compiling with 
      <link linkend="configure.enable-trans-sid">
      <literal>--enable-trans-sid</literal></link>.
      From PHP 4.2.0, trans-sid feature is always compiled.
     </simpara>
     <simpara>
      URL based session management has additional security risks
      compared to cookie based session management. Users may send
      a URL that contains an active session ID to their friends by
      email or users may save a URL that contains a session ID to
      their bookmarks and access your site with the same session ID
      always, for example.
     </simpara>
    </note>
   </listitem>
  </varlistentry>
  
  <varlistentry id="ini.session.bug-compat-42">
   <term>
    <parameter>session.bug_compat_42</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     PHP versions 4.2.3 and lower have an undocumented feature/bug that
     allows you to initialize a session variable in the global scope,
     albeit <link linkend="ini.register-globals">register_globals</link>
     is disabled.  PHP 4.3.0 and later will warn you, if this feature is
     used, and if <link linkend="ini.session.bug-compat-warn">
     session.bug_compat_warn</link> is also enabled.  This feature/bug can be
     disabled by disabling this directive.
    </simpara>
   </listitem>
  </varlistentry>
  
  <varlistentry id="ini.session.bug-compat-warn">
   <term>
    <parameter>session.bug_compat_warn</parameter>
    <type>boolean</type>
   </term>
   <listitem>
    <simpara>
     PHP versions 4.2.3 and lower have an undocumented feature/bug that
     allows you to initialize a session variable in the global scope,
     albeit <link linkend="ini.register-globals">register_globals</link>
     is disabled.  PHP 4.3.0 and later will warn you, if this feature is
     used by enabling both 
     <link linkend="ini.session.bug-compat-42">session.bug_compat_42</link>
     and <link linkend="ini.session.bug-compat-warn">
     session.bug_compat_warn</link>.
    </simpara>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.hash-function">
   <term>
    <parameter>session.hash_function</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.hash_function</literal> allows you to specify the hash
     algorithm used to generate the session IDs. '0' means MD5 (128 bits) and
     '1' means SHA-1 (160 bits).
    </simpara>
    <note>
     <para>
      This was introduced in PHP 5.
     </para>
    </note>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.session.hash-bits-per-character">
   <term>
    <parameter>session.hash_bits_per_character</parameter>
    <type>integer</type>
   </term>
   <listitem>
    <simpara>
     <literal>session.hash_bits_per_character</literal> allows you to define
     how many bits are stored in each character when converting the binary
     hash data to something readable. The possible values are '4' (0-9, a-f),
     '5' (0-9, a-v), and '6' (0-9, a-z, A-Z, "-", ",").
    </simpara>
    <note>
     <para>
      This was introduced in PHP 5.
     </para>
    </note>
   </listitem>
  </varlistentry>

  <varlistentry id="ini.url-rewriter.tags">
   <term>
    <parameter>url_rewriter.tags</parameter>
    <type>string</type>
   </term>
   <listitem>
    <simpara>
     <literal>url_rewriter.tags</literal> specifies which HTML tags
     are rewritten to include session id if transparent sid support
     is enabled. Defaults to
     <literal>a=href,area=href,frame=src,input=src,form=fakeentry,fieldset=</literal>
    </simpara>
    <note>
     <simpara>
      If you want XHTML conformity, remove the <literal>form</literal> entry and
      use the &lt;fieldset&gt; tags around your form fields.
     </simpara>
    </note>
   </listitem>
  </varlistentry>
 </variablelist>
 </para>

 <para>
  The <link
  linkend="ini.track-vars"><literal>track_vars</literal></link> and
  <link
  linkend="ini.register-globals"><literal>register_globals</literal></link>
  configuration settings influence how the session variables get
  stored and restored.
 </para>

 <note>
  <para>
   As of PHP 4.0.3, <link
   linkend="ini.track-vars"><literal>track_vars</literal></link> is
   always turned on.
  </para>
 </note>

</section>

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