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  <refentry id="function.setcookie">
   <refnamediv>
    <refname>setcookie</refname>
    <refpurpose>Send a cookie</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>setcookie</methodname>
      <methodparam><type>string</type><parameter>name</parameter></methodparam>
      <methodparam choice="opt"><type>string</type><parameter>value</parameter></methodparam>
      <methodparam choice="opt"><type>int</type><parameter>expire</parameter></methodparam>
      <methodparam choice="opt"><type>string</type><parameter>path</parameter></methodparam>
      <methodparam choice="opt"><type>string</type><parameter>domain</parameter></methodparam>
      <methodparam choice="opt"><type>bool</type><parameter>secure</parameter></methodparam>
     </methodsynopsis>
    <para>
     <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 your
     script (this is a protocol restriction). This requires that you
     place calls to this function prior to any output, including
     <literal>&lt;html&gt;</literal> and <literal>&lt;head&gt;</literal> tags
     as well as any whitespace. 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.
    </para>
    <note>
     <para>
      As of PHP 4, you can use output buffering to send output prior to the 
      call of this function, with the overhead of all of your output to the 
      browser being buffered in the server until you send it. You can do this 
      by calling <function>ob_start</function> and 
      <function>ob_end_flush</function> in your script, or setting the 
      <literal>output_buffering</literal> configuration directive on in your 
      &php.ini; or server configuration files.
     </para>
    </note>    
    <para>
     All the arguments except the <parameter>name</parameter> argument
     are optional. You may also replace an argument with an empty string
     (<emphasis>&quot;&quot;</emphasis>) in order to skip that
     argument. Because the <parameter>expire</parameter>
     argument is integer, it cannot
     be skipped with an empty string, use a zero (<emphasis>0</emphasis>)
     instead.  The following table explains each parameter of the 
     <function>setcookie</function> function, be sure to read the  
     <ulink url="&spec.cookies;">Netscape cookie specification</ulink> for
     specifics on how each <function>setcookie</function> parameter works
     and <ulink url="&url.rfc;2965">RFC 2965</ulink> for additional
     information on how HTTP cookies work. 
    </para>
    <para>
     <table>
      <title><function>setcookie</function> parameters explained</title>
      <tgroup cols="3">
       <thead>
        <row>
         <entry>Parameter</entry>
         <entry>Description</entry>
         <entry>Examples</entry>
        </row>
       </thead>
       <tbody>
        <row>
         <entry><parameter>name</parameter></entry>
         <entry>
          The name of the cookie.
         </entry>
         <entry>
          'cookiename' is called as <varname>$_COOKIE['cookiename']</varname>
         </entry>
        </row>
        <row>
         <entry><parameter>value</parameter></entry>
         <entry>
          The value of the cookie.  This value is stored on the clients
          computer; do not store sensitive information.
         </entry>
         <entry>
          Assuming the <parameter>name</parameter> is 'cookiename', this
          value is retrieved through <varname>$_COOKIE['cookiename']</varname>
         </entry>
        </row>
        <row>
         <entry><parameter>expire</parameter></entry>
         <entry>
          The time the cookie expires.  This is a Unix timestamp so is
          in number of seconds since the epoch.  In other words, you'll
          most likely set this with the <function>time</function> function
          plus the number of seconds before you want it to expire.  Or
          you might use <function>mktime</function>.
         </entry>
         <entry>
          <literal>time()+60*60*24*30</literal> will set the cookie to
          expire in 30 days.  If not set, the cookie will expire at
          the end of the session (when the browser closes).
         </entry>
        </row>
        <row>
         <entry><parameter>path</parameter></entry>
         <entry>
          The path on the server in which the cookie will be available on.
         </entry>
         <entry>
          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.
         </entry>
        </row>
        <row>
         <entry><parameter>domain</parameter></entry>
         <entry>
          The domain that the cookie is available.
         </entry>
         <entry>
          To make the cookie available on all subdomains of example.com
          then you'd set it to <literal>'.example.com'</literal>.  The
          <literal>.</literal> is not required but makes it compatible 
          with more browsers.  Setting it to <literal>www.example.com</literal>
          will make the cookie only available in the <literal>www</literal>
          subdomain.  Refer to tail matching in the 
          <ulink url="&spec.cookies;">spec</ulink> for details.
         </entry>
        </row>
        <row>
         <entry><parameter>secure</parameter></entry>
         <entry>
          Indicates that the cookie should only be transmitted over a 
          secure HTTPS connection. When set to &true;, the
          cookie will only be set if a secure connection exists. The default
          is &false;.
         </entry>
         <entry>
          <literal>0</literal> or <literal>1</literal>
         </entry>
        </row>
       </tbody>
      </tgroup>
     </table>
    </para>
    <para>
     Once the cookies have been set, they can be accessed on the next page load
     with the <link linkend="reserved.variables.cookies">$_COOKIE</link> or 
     <varname>$HTTP_COOKIE_VARS</varname> arrays.  Note,
     <link linkend="language.variables.superglobals">autoglobals</link> 
     such as <varname>$_COOKIE</varname> became available in PHP
     <ulink url="&url.php.release4.1.0;">4.1.0</ulink>.
     <varname>$HTTP_COOKIE_VARS</varname> has existed since PHP 3.  Cookie
     values also exist in <link linkend="reserved.variables.request">
     $_REQUEST</link>.
    </para>
    <note>
     <para>
      If the PHP directive <link linkend="ini.register-globals">register_globals</link>
      is set to <literal>on</literal> then cookie values will also be made into
      variables.  In our examples below, <varname>$TestCookie</varname> will
      exist.  It's recommended to use <varname>$_COOKIE</varname>.
     </para>
    </note>
    <para>
     Common Pitfalls:
     <itemizedlist>
      <listitem>
       <simpara>
        Cookies will not become visible until the next loading of a page that 
        the cookie should be visible for.  To test if a cookie was successfully 
        set, check for the cookie on a next loading page before the cookie 
        expires.  Expire time is set via the <parameter>expire</parameter> 
        parameter.  A nice way to debug the existence of cookies is by
        simply calling <literal>print_r($_COOKIE);</literal>.
       </simpara>
      </listitem>
      <listitem>
       <simpara>
        Cookies must be deleted with the same parameters as they were set with.
        If the value argument is an empty string, or &false;, and all other arguments
        match a previous call to setcookie, then the cookie with the specified
        name will be deleted from the remote client.
       </simpara>
      </listitem>
      <listitem>
       <simpara>
        Because setting a cookie with a value of &false; will try to delete the cookie,
        you should not use boolean values. 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 your 
        PHP scripts as arrays but separate cookies are stored on the users 
        system.  Consider <function>explode</function> or
        <function>serialize</function> to set one cookie with multiple names 
        and values.
       </simpara>
      </listitem>
     </itemizedlist>
    </para>
    <simpara>
     In PHP 3, multiple calls to <function>setcookie</function> in the same
     script will be performed in reverse order. If you are trying to
     delete one cookie before inserting another you should put the
     insert before the delete. As of PHP 4, multiple calls to
     <function>setcookie</function> are performed in the order called.
    </simpara>
    <para>
     Some examples follow how to send cookies:
     <example>
      <title><function>setcookie</function> send example</title>
      <programlisting role="php">
<![CDATA[
<?php
$value = 'something from somewhere';

setcookie("TestCookie", $value);
setcookie("TestCookie", $value, time()+3600);  /* expire in 1 hour */
setcookie("TestCookie", $value, time()+3600, "/~rasmus/", ".example.com", 1);
?>
]]>
      </programlisting>
     </example>
    </para>
    <para>
     Note that the value portion of the cookie will automatically be
     urlencoded when you send the cookie, and when it is received, it
     is automatically decoded and assigned to a variable by the same
     name as the cookie name. If you don't want this, you can use
     <function>setrawcookie</function> instead if you are using PHP 5. To see
     the contents of our test cookie in a script, simply use one of the
     following examples:
    </para>
    <para>
     <informalexample>
      <programlisting role="php">
<![CDATA[
<?php
// Print an individual cookie
echo $_COOKIE["TestCookie"];
echo $HTTP_COOKIE_VARS["TestCookie"];

// Another way to debug/test is to view all cookies
print_r($_COOKIE);
?>
]]>
      </programlisting>
     </informalexample>
    </para>
    <para>
     When deleting a cookie you should assure that the expiration date
     is in the past, to trigger the removal mechanism in your browser.
     Examples follow how to delete cookies sent in previous example:
    </para>
    <para>
     <example>
      <title><function>setcookie</function> delete example</title>
      <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>
    </para>
    <para>
     You may also set array cookies by using array notation in the
     cookie name. This has the effect of setting as many cookies as
     you have array elements, but when the cookie is received by your
     script, the values are all placed in an array with the cookie's
     name:
    </para>
    <para>
     <example>
      <title><function>setcookie</function> and arrays</title>
      <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 => $value) {
        echo "$name : $value <br />\n";
    }
}
?>
]]>
      </programlisting>
      <para>
       which prints
      </para>
      <screen>
<![CDATA[
three : cookiethree
two : cookietwo
one : cookieone
]]>
      </screen>
     </example>
    </para>
    <note>
     <para>
      The following RFC's may also be useful:
      <ulink url="&url.rfc;2109">RFC 2109</ulink> and 
      <ulink url="&url.rfc;2965">RFC 2695</ulink>
     </para>
     <para>
      You may notice the <parameter>expire</parameter> parameter takes on a
      Unix timestamp, as opposed to the date format <literal>Wdy, DD-Mon-YYYY
      HH:MM:SS GMT</literal>, this is because PHP does this conversion
      internally.
     </para>
     <para>
      <parameter>expire</parameter> is compared to the client's time which can
      differ from server's time.
     </para>
    </note>
    <note>
     <simpara>
      Microsoft Internet Explorer 4 with Service Pack 1 applied does
      not correctly deal with cookies that have their path parameter
      set.
     </simpara>
     <simpara>
      Netscape Communicator 4.05 and Microsoft Internet Explorer 3.x
      appear to handle cookies incorrectly when the path and time
      are not set.
     </simpara>
    </note>
    <para>
     See also <function>header</function>, <function>setrawcookie</function>
     and the <link linkend="features.cookies">cookies section</link>.
    </para>
   </refsect1>
  </refentry>

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