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https://github.com/sigmasternchen/php-doc-en
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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@283836 c90b9560-bf6c-de11-be94-00142212c4b1
114 lines
3.8 KiB
XML
114 lines
3.8 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!-- $Revision$ -->
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<!-- Purpose: basic.session -->
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<!-- Membership: core -->
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<book xml:id="book.session" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
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<title>Session Handling</title>
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<titleabbrev>Sessions</titleabbrev>
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<!-- {{{ preface -->
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<preface xml:id="intro.session">
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&reftitle.intro;
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<para>
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Session support in PHP consists of a way to preserve certain data
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across subsequent accesses. This enables you to build more
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customized applications and increase the appeal of your web site.
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</para>
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<para>
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A visitor accessing your web site is assigned a unique id, the
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so-called session id. This is either stored in a cookie on the
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user side or is propagated in the URL.
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</para>
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<para>
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The session support allows you to register arbitrary numbers of
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variables to be preserved across requests. When a visitor accesses
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your site, PHP will check automatically (if <link
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linkend="ini.session.auto-start">session.auto_start</link>
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is set to 1) or on your request (explicitly through
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<function>session_start</function> or implicitly through
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<function>session_register</function>) whether a specific session
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id has been sent with the request. If this is the case, the prior
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saved environment is recreated.
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</para>
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<caution>
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<para>
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If you turn on <link linkend="ini.session.auto-start">
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session.auto_start</link> then the only way to put objects
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into your sessions is to load its class definition using
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<link linkend="ini.auto-prepend-file">auto_prepend_file</link>
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in which you load the class definition else you will have to
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<function>serialize</function> your object
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and <function>unserialize</function> it
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afterwards.
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</para>
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</caution>
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<para>
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All registered variables are serialized after the request
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finishes. Registered variables which are undefined are marked as
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being not defined. On subsequent accesses, these are not defined
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by the session module unless the user defines them later.
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</para>
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<warning>
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<para>
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Some types of data can not be serialized thus stored in sessions. It
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includes <type>resource</type> variables or objects with circular
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references (i.e. objects which passes a reference to itself to another
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object).
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</para>
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</warning>
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<note>
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<para>
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Session handling was added in PHP 4.0.0.
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</para>
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</note>
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<note>
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<para>
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Please note when working with sessions that a record of a session
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is not created until a variable has been registered using the
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<function>session_register</function> function or by adding a new
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key to the <varname>$_SESSION</varname> superglobal array. This
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holds true regardless of if a session has been started using the
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<function>session_start</function> function.
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</para>
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</note>
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<note>
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<para>
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PHP 5.2.2 introduced an undocumented feature to store session files
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in "/tmp" even if <link linkend="ini.open-basedir">open_basedir</link>
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was enabled and "/tmp" is not explicitly added to the allowed paths
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list. This feature has been removed from PHP as of PHP 5.3.0.
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</para>
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</note>
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</preface>
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<!-- }}} -->
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&reference.session.setup;
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&reference.session.constants;
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&reference.session.examples;
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&reference.session.security;
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&reference.session.reference;
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</book>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"../../../manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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