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<HTML
><HEAD
><TITLE
>header</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.57"><LINK
REL="HOME"
TITLE="PHP Manual"
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TITLE="HTTP functions"
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><BODY
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BGCOLOR="#FFFFFF"
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VLINK="#840084"
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><DIV
CLASS="NAVHEADER"
><TABLE
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BORDER="0"
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CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>PHP Manual</TH
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><TR
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><A
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>Prev</A
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></TD
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><HR
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><H1
><A
NAME="function.header"
>header</A
></H1
><DIV
CLASS="refnamediv"
><A
NAME="AEN13154"
></A
><P
>    (PHP3 , PHP4 )</P
>header&nbsp;--&nbsp;Send a raw HTTP header</DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN13157"
></A
><H2
>Description</H2
><DIV
CLASS="funcsynopsis"
><A
NAME="AEN13159"
></A
><P
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="function"
>header</B
></CODE
> (string string)</CODE
></P
><P
></P
></DIV
><P
>&#13;     The <B
CLASS="function"
>Header()</B
> function is used at the top of an
     <SPAN
CLASS="acronym"
>HTML</SPAN
> file to send raw <SPAN
CLASS="acronym"
>HTTP</SPAN
>
     header strings.  See the <A
HREF="http://www.w3.org/Protocols/rfc2616/rfc2616"
TARGET="_top"
>HTTP 1.1
     Specification</A
> for more information on raw http headers.
     <I
CLASS="emphasis"
>Note:</I
> Remember that the
     <B
CLASS="function"
>Header()</B
> function must be called before any
     actual output is sent either by normal HTML tags or from PHP. It
     is a very common error to read code with
     <A
HREF="function.include.html"
><B
CLASS="function"
>include()</B
></A
> or with auto_prepend and have spaces
     or empty lines in this code that force output before
     <B
CLASS="function"
>header()</B
> is called.
    </P
><P
>&#13;     There are two special-case header calls.  The first is the
     "Location" header.  Not only does it send this header
     back to the browser, it also returns a REDIRECT status code to
     Apache.  From a script writer's point of view this should not be
     important, but for people who understand Apache internals it is
     important to understand.
     <DIV
CLASS="informalexample"
><A
NAME="AEN13175"
></A
><P
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><PRE
CLASS="programlisting"
>&#13;header ("Location: http://www.php.net"); /* Redirect browser 
                                            to PHP web site */
exit;                 /* Make sure that code below does 
                         not get executed when we redirect. */
      </PRE
></TD
></TR
></TABLE
><P
></P
></DIV
>
    </P
><P
>&#13;     The second special-case is any header that starts with the
     string, "HTTP/" (case is not significant).  For
     example, if you have your ErrorDocument 404 Apache directive
     pointed to a PHP script, it would be a good idea to make sure
     that your PHP script is actually generating a 404.  The first
     thing you do in your script should then be:
     <DIV
CLASS="informalexample"
><A
NAME="AEN13178"
></A
><P
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><PRE
CLASS="programlisting"
>&#13;header ("HTTP/1.0 404 Not Found");
      </PRE
></TD
></TR
></TABLE
><P
></P
></DIV
>
    </P
><P
>&#13;     PHP scripts often generate dynamic HTML that must not be cached
     by the client browser or any proxy caches between the server and the
     client browser. Many proxies and clients can be forced to disable
     caching with
     <DIV
CLASS="informalexample"
><A
NAME="AEN13181"
></A
><P
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
WIDTH="100%"
><TR
><TD
><PRE
CLASS="programlisting"
>&#13;header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT");    // Date in the past
header ("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
                                                      // always modified
header ("Cache-Control: no-cache, must-revalidate");  // HTTP/1.1
header ("Pragma: no-cache");                          // HTTP/1.0
      </PRE
></TD
></TR
></TABLE
><P
></P
></DIV
>
    </P
><P
>&#13;     See also <A
HREF="function.headers-sent.html"
><B
CLASS="function"
>headers_sent()</B
></A
>
    </P
></DIV
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><HR
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><TD
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>Prev</A
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></TD
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>