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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@115749 c90b9560-bf6c-de11-be94-00142212c4b1
91 lines
3 KiB
XML
91 lines
3 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!-- $Revision: 1.3 $ -->
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<!-- splitted from ./en/functions/filesystem.xml, last change in rev 1.39 -->
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<refentry id="function.is-uploaded-file">
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<refnamediv>
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<refname>is_uploaded_file</refname>
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<refpurpose>Tells whether the file was uploaded via HTTP POST</refpurpose>
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</refnamediv>
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<refsect1>
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<title>Description</title>
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<methodsynopsis>
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<type>bool</type><methodname>is_uploaded_file</methodname>
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<methodparam><type>string</type><parameter>filename</parameter></methodparam>
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</methodsynopsis>
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<para>
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Returns &true; if the file named by <parameter>filename</parameter> was
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uploaded via HTTP POST. This is useful to help ensure that a
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malicious user hasn't tried to trick the script into working on
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files upon which it should not be working--for instance,
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<filename>/etc/passwd</filename>.
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</para>
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<para>
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This sort of check is especially important if there is any chance
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that anything done with uploaded files could reveal their
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contents to the user, or even to other users on the same
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system.
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</para>
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<para>
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<function>is_uploaded_file</function> is available only in
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versions of PHP 3 after PHP 3.0.16, and in versions of PHP 4
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after 4.0.2. If you are stuck using an earlier version, you can
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use the following function to help protect yourself:
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<note>
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<para>
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The following example will <emphasis>not</emphasis> work in
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versions of PHP 4 after 4.0.2. It depends on internal
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functionality of PHP which changed after that version.
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</para>
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</note>
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<programlisting role="php">
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<![CDATA[
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<?php
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/* Userland test for uploaded file. */
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function is_uploaded_file($filename) {
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if (!$tmp_file = get_cfg_var('upload_tmp_dir')) {
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$tmp_file = dirname(tempnam('', ''));
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}
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$tmp_file .= '/' . basename($filename);
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/* User might have trailing slash in php.ini... */
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return (ereg_replace('/+', '/', $tmp_file) == $filename);
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}
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/* This is how to use it, since you also don't have
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* move_uploaded_file() in these older versions: */
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if (is_uploaded_file($HTTP_POST_FILES['userfile'])) {
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copy($HTTP_POST_FILES['userfile'], "/place/to/put/uploaded/file");
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} else {
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echo "Possible file upload attack: filename '$HTTP_POST_FILES[userfile]'.";
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}
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?>
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]]>
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</programlisting>
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</para>
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<para>
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See also <function>move_uploaded_file</function>, and the section
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<link linkend="features.file-upload">Handling file uploads</link>
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for a simple usage example.
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</para>
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</refsect1>
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</refentry>
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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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