archived-doc-en/reference/network/functions/setcookie.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xml:id="function.setcookie" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>setcookie</refname>
  <refpurpose>Send a cookie</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>setcookie</methodname>
   <methodparam><type>string</type><parameter>name</parameter></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>value</parameter><initializer>""</initializer></methodparam>
   <methodparam choice="opt"><type>int</type><parameter>expires_or_options</parameter><initializer>0</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>path</parameter><initializer>""</initializer></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>domain</parameter><initializer>""</initializer></methodparam>
   <methodparam choice="opt"><type>bool</type><parameter>secure</parameter><initializer>&false;</initializer></methodparam>
   <methodparam choice="opt"><type>bool</type><parameter>httponly</parameter><initializer>&false;</initializer></methodparam>
  </methodsynopsis>
  <simpara>Alternative signature available as of PHP 7.3.0 (not supported with named parameters):</simpara>
  <methodsynopsis>
   <type>bool</type><methodname>setcookie</methodname>
   <methodparam><type>string</type><parameter>name</parameter></methodparam>
   <methodparam choice="opt"><type>string</type><parameter>value</parameter><initializer>""</initializer></methodparam>
   <methodparam choice="opt"><type>array</type><parameter>options</parameter><initializer>[]</initializer></methodparam>
  </methodsynopsis>
  <simpara>
   <function>setcookie</function> defines a cookie to be sent along with the
   rest of the HTTP headers. Like other headers, cookies must be sent
   <emphasis>before</emphasis> any output from the script (this is a
   protocol restriction). This requires that this function is called
   prior to any output, including <literal>&lt;html&gt;</literal> and
   <literal>&lt;head&gt;</literal> tags as well as any whitespace.
  </simpara>
  <simpara>
   Once the cookies have been set, they can be accessed on the next page load
   with the <varname>$_COOKIE</varname> array.
   Cookie
   values may also exist in <varname>$_REQUEST</varname>.
  </simpara>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <link xlink:href="&url.rfc;6265">RFC 6265</link> provides the normative
   reference on how each <function>setcookie</function> parameter is
   interpreted.
   <variablelist>
    <varlistentry>
     <term><parameter>name</parameter></term>
     <listitem>
      <simpara>
       The name of the cookie.
      </simpara>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>value</parameter></term>
     <listitem>
      <simpara>
       The value of the cookie.  This value is stored on the clients computer;
       do not store sensitive information.  Assuming the
       <parameter>name</parameter> is <literal>'cookiename'</literal>, this
       value is retrieved through <varname>$_COOKIE['cookiename']</varname>
      </simpara>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>expires_or_options</parameter></term>
     <listitem>
      <simpara>
       The time the cookie expires.  This is a Unix timestamp so is
       in number of seconds since the epoch.
       One way to set this is by adding the number of seconds before the cookie
       should expire to the result of calling <function>time</function>.
       For instance, <literal>time()+60*60*24*30</literal> will set the cookie to
       expire in 30 days.
       Another option is to use the <function>mktime</function> function.
       If set to <literal>0</literal>, or omitted, the cookie will expire at
       the end of the session (when the browser closes).
      </simpara>
      <note>
       <simpara>
        The <parameter>expires_or_options</parameter> parameter takes a
        Unix timestamp, as opposed to the date format <literal>Wdy, DD-Mon-YYYY
        HH:MM:SS GMT</literal>, because PHP does this conversion
        internally.
       </simpara>
      </note>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>path</parameter></term>
     <listitem>
      <simpara>
       The path on the server in which the cookie will be available on.
       If set to <literal>'/'</literal>, the cookie will be available
       within the entire <parameter>domain</parameter>.  If set to
       <literal>'/foo/'</literal>, the cookie will only be available
       within the <literal>/foo/</literal> directory and all
       sub-directories such as <literal>/foo/bar/</literal> of
       <parameter>domain</parameter>.  The default value is the
       current directory that the cookie is being set in.
      </simpara>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>domain</parameter></term>
     <listitem>
      <simpara>
       The (sub)domain that the cookie is available to. Setting this to a
       subdomain (such as <literal>'www.example.com'</literal>) will make the
       cookie available to that subdomain and all other sub-domains of it (i.e.
       w2.www.example.com). To make the cookie available to the whole domain
       (including all subdomains of it), simply set the value to the domain
       name (<literal>'example.com'</literal>, in this case).
      </simpara>
      <simpara>
       Older browsers still implementing the deprecated
       <link xlink:href="&url.rfc;2109">RFC 2109</link> may require a leading
       <literal>.</literal> to match all subdomains.
      </simpara>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>secure</parameter></term>
     <listitem>
      <simpara>
       Indicates that the cookie should only be transmitted over a
       secure HTTPS connection from the client. When set to &true;, the
       cookie will only be set if a secure connection exists.
       On the server-side, it's on the programmer to send this
       kind of cookie only on secure connection (e.g. with respect to
       <varname>$_SERVER["HTTPS"]</varname>).
      </simpara>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>httponly</parameter></term>
     <listitem>
      <simpara>
       When &true; the cookie will be made accessible only through the HTTP
       protocol. This means that the cookie won't be accessible by
       scripting languages, such as JavaScript. It has been suggested that
       this setting can effectively help to reduce identity theft through
       XSS attacks (although it is not supported by all browsers), but that
       claim is often disputed.
       &true; or &false;
      </simpara>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>options</parameter></term>
     <listitem>
      <simpara>
       An associative <type>array</type> which may have any of the keys
       <literal>expires</literal>, <literal>path</literal>, <literal>domain</literal>,
       <literal>secure</literal>, <literal>httponly</literal> and <literal>samesite</literal>.
      </simpara>
      <simpara>
       The values have the same meaning as described for the
       parameters with the same name. The value of the <literal>samesite</literal>
       element should be either <literal>None</literal>, <literal>Lax</literal>
       or <literal>Strict</literal>.
       If any of the allowed options are not given, their default values are the
       same as the default values of the explicit parameters. If the
       <literal>samesite</literal> element is omitted, no SameSite cookie
       attribute is set.
      </simpara>

      <note>
       <simpara>
        To set a cookie that includes attributes that aren't among the keys listed,
        use <function>header</function>.
       </simpara>
      </note>
      <note>
       <simpara>
        If <literal>samesite</literal> is <literal>"None"</literal> then
        <literal>secure</literal> must also be enabled or the cookie will be
        blocked by the client.
       </simpara>
      </note>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <simpara>
   If output exists prior to calling this function,
   <function>setcookie</function> will fail and return &false;. If
   <function>setcookie</function> successfully runs, it will return &true;.
   This does not indicate whether the user accepted the cookie.
  </simpara>
 </refsect1>

 <refsect1 role="errors">
  &reftitle.errors;
  <simpara>
   If the <parameter>options</parameter> array contains unsupported keys:
  </simpara>
  <itemizedlist>
   <listitem>
    <simpara>
     Prior to PHP 8.0.0, an <constant>E_WARNING</constant> was generated.
    </simpara>
   </listitem>
   <listitem>
    <simpara>
     As of PHP 8.0.0, a <exceptionname>ValueError</exceptionname> is thrown.
    </simpara>
   </listitem>
  </itemizedlist>
 </refsect1>

 <refsect1 role="changelog">
  &reftitle.changelog;
  <informaltable>
   <tgroup cols="2">
    <thead>
     <row>
      <entry>&Version;</entry>
      <entry>&Description;</entry>
     </row>
    </thead>
    <tbody>
     <row>
      <entry>8.2.0</entry>
      <entry>
       The date format of the cookie is now <literal>'D, d M Y H:i:s \G\M\T'</literal>;
       previously it was <literal>'D, d-M-Y H:i:s T'</literal>.
      </entry>
     </row>
     <row>
      <entry>8.0.0</entry>
      <entry>
       Passing unsupported keys now throws a <exceptionname>ValueError</exceptionname>
       instead of emitting an <constant>E_WARNING</constant>.
      </entry>
     </row>
     <row>
      <entry>7.3.0</entry>
      <entry>
       An alternative signature supporting an <parameter>options</parameter>
       array has been added. This signature supports also setting of the
       SameSite cookie attribute.
      </entry>
     </row>
    </tbody>
   </tgroup>
  </informaltable>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <simpara>
   The effects of the following examples can be observed using the browser
   developer tools cookie list (usually in the Storage or Application tab).
  </simpara>
  <example>
   <title><function>setcookie</function> send example</title>
   <programlisting role="php">
<![CDATA[
<?php

$value = 'something from somewhere';

// Set a "session cookie" that expires when the browser is closed
setcookie("TestCookie", $value);
// Set a cookie that expires in 1 hour
setcookie("TestCookie", $value, time()+3600);
// Set a cookie that applies only to a specific path on a specific domain
// Note that the domain used should match the site domain
setcookie("TestCookie", $value, time()+3600, "/~rasmus/", "example.com", true);

?>
]]>
   </programlisting>
  </example>
  <simpara>
   Note that the value portion of the cookie will automatically be
   urlencoded and decoded by PHP. This can be avoided by using
   <function>setrawcookie</function> instead.
  </simpara>
  <simpara>
   To see the contents of the cookies set in the above example on a later
   request:
  </simpara>
  <informalexample>
   <programlisting role="php">
<![CDATA[
<?php
// Print an individual cookie
echo $_COOKIE["TestCookie"];

// Another way to debug/test is to view all cookies
print_r($_COOKIE);
?>
]]>
   </programlisting>
  </informalexample>
  <example>
   <title><function>setcookie</function> delete example</title>
   <simpara>
    To delete a cookie set the expiration date to a value in the past
    (but not zero, which is reserved for session cookies).
   </simpara>
   <simpara>
    To delete the cookies set in previous example:
   </simpara>
   <programlisting role="php">
<![CDATA[
<?php
// set the expiration date to one hour ago
setcookie("TestCookie", "", time() - 3600);
setcookie("TestCookie", "", time() - 3600, "/~rasmus/", "example.com", 1);
?>
]]>
   </programlisting>
  </example>
  <example>
   <title><function>setcookie</function> and arrays</title>
   <simpara>
    An "array of cookies" can be set by using array notation in the
    cookie name. This has the effect of setting as many cookies as
    there are array elements, but when the cookie is received by the
    script, the values are all placed in an array with the cookie's
    name:
   </simpara>
   <programlisting role="php">
<![CDATA[
<?php
// set the cookies
setcookie("cookie[three]", "cookiethree");
setcookie("cookie[two]", "cookietwo");
setcookie("cookie[one]", "cookieone");

// after the page reloads, print them out
if (isset($_COOKIE['cookie'])) {
    foreach ($_COOKIE['cookie'] as $name => $value) {
        $name = htmlspecialchars($name);
        $value = htmlspecialchars($value);
        echo "$name : $value <br />\n";
    }
}
?>
]]>
   </programlisting>
   &example.outputs;
   <screen>
<![CDATA[
three : cookiethree
two : cookietwo
one : cookieone
]]>
   </screen>
  </example>
  <note>
   <simpara>
    Using separator characters such as <literal>[</literal> and <literal>]</literal>
    as part of the cookie name is not compliant to RFC 6265, section 4, but supposed
    to be supported by user agents according to RFC 6265, section 5.
   </simpara>
  </note>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <simpara>
    Output buffering can be used to allow script output prior to the
    call of this function. All output will be buffered until it is flushed
    (either explicitly or at the end of the script execution). This is done
    by calling <function>ob_start</function> and
    <function>ob_end_flush</function> in the script, or setting the
    <literal>output_buffering</literal> configuration directive on in the
    &php.ini; or server configuration files.
   </simpara>
  </note>
  <para>
   Common Pitfalls:
   <itemizedlist>
    <listitem>
     <simpara>
      Cookies will not become visible until the next loading of a page that
      the cookie should be visible for.  To test if a cookie was successfully
      set, check for the cookie on a next loading page before the cookie
      expires.  Expire time is set via the <parameter>expires_or_options</parameter>
      parameter.  A nice way to debug the existence of cookies is by
      simply calling <literal>print_r($_COOKIE);</literal>.
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      Cookies must be deleted with the same parameters as they were set with.
      If the <parameter>value</parameter> argument is an empty string, and all other arguments
      match a previous call to <function>setcookie</function>, then the cookie with the specified
      name will be deleted from the remote client.
      This is internally achieved by setting value to <literal>'deleted'</literal> and expiration
      time in the past.
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      Because setting a cookie with a value of &false; will try to delete the cookie,
      boolean values should not be used. Instead, use <emphasis>0</emphasis> for &false;
      and <emphasis>1</emphasis> for &true;.
     </simpara>
    </listitem>
    <listitem>
     <simpara>
      Cookies names can be set as array names and will be available to the
      PHP scripts as arrays but separate cookies are stored by the browser.
      Consider <function>json_encode</function> to set one cookie with multiple
      names and values. It is not recommended to use <function>serialize</function>
      for this purpose because it can result in security holes.
     </simpara>
    </listitem>
   </itemizedlist>
  </para>
  <simpara>
   Multiple calls to <function>setcookie</function> are performed in the order called.
  </simpara>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <simplelist>
   <member><function>header</function></member>
   <member><function>setrawcookie</function></member>
   <member><link linkend="features.cookies">cookies section</link></member>
   <member><link xlink:href="&url.rfc;6265">RFC 6265</link></member>
   <member><link xlink:href="&url.rfc;2109">RFC 2109</link></member>
  </simplelist>
 </refsect1>

</refentry>

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