Sophie: php-manual-en-4.3.0-2mdk noarch

php-manual-en-4.3.0-2mdk.noarch.rpm

<HTML
><HEAD
><TITLE
>stream_register_wrapper</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
REL="HOME"
TITLE="PHP Manual"
HREF="index.html"><LINK
REL="UP"
TITLE="Stream functions"
HREF="ref.stream.html"><LINK
REL="PREVIOUS"
TITLE="stream_register_filter"
HREF="function.stream-register-filter.html"><LINK
REL="NEXT"
TITLE="stream_select"
HREF="function.stream-select.html"><META
HTTP-EQUIV="Content-type"
CONTENT="text/html; charset=ISO-8859-1"></HEAD
><BODY
CLASS="refentry"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="3"
ALIGN="center"
>PHP Manual</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="bottom"
><A
HREF="function.stream-register-filter.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="function.stream-select.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="function.stream-register-wrapper"
></A
>stream_register_wrapper</H1
><DIV
CLASS="refnamediv"
><A
NAME="AEN88652"
></A
><P
>    (PHP 4 &#62;= 4.3.0)</P
>stream_register_wrapper&nbsp;--&nbsp;Register a URL wrapper implemented as a PHP class</DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN88655"
></A
><H2
>Description</H2
>boolean <B
CLASS="methodname"
>stream_register_wrapper</B
> ( string protocol, string classname)<BR
></BR
><P
>&#13;     <B
CLASS="function"
>stream_register_wrapper()</B
> allows you to implement
     your own protocol handlers and streams for use with all the other
     filesystem functions (such as <A
HREF="function.fopen.html"
><B
CLASS="function"
>fopen()</B
></A
>,
     <A
HREF="function.fread.html"
><B
CLASS="function"
>fread()</B
></A
> etc.).
    </P
><P
>&#13;     To implement a wrapper, you need to define a class with a number of
     member functions, as defined below. When someone fopens your stream,
     PHP will create an instance of <TT
CLASS="parameter"
><I
>classname</I
></TT
> and
     then call methods on that instance.  You must implement the methods
     exactly as described below - doing otherwise will lead to undefined
     behaviour.
    </P
><P
>&#13;     <B
CLASS="function"
>stream_register_wrapper()</B
> will return <TT
CLASS="constant"
><B
>FALSE</B
></TT
> if the
     <TT
CLASS="parameter"
><I
>protocol</I
></TT
> already has a handler.
    </P
>boolean <B
CLASS="methodname"
>stream_open</B
> ( string path, string mode, int options, string opened_path)<BR
></BR
><P
>&#13;     This method is called immediately after your stream object is
     created.  <TT
CLASS="parameter"
><I
>path</I
></TT
> specifies the URL that was
     passed to <A
HREF="function.fopen.html"
><B
CLASS="function"
>fopen()</B
></A
> and that this object is
     expected to retrieve.  You can use <A
HREF="function.parse-url.html"
><B
CLASS="function"
>parse_url()</B
></A
>
     to break it apart.
    </P
><P
>&#13;     <TT
CLASS="parameter"
><I
>mode</I
></TT
> is the mode used to open the file,
     as detailed for <A
HREF="function.fopen.html"
><B
CLASS="function"
>fopen()</B
></A
>.  You are responsible
     for checking that <TT
CLASS="parameter"
><I
>mode</I
></TT
> is valid for the
     <TT
CLASS="parameter"
><I
>path</I
></TT
> requested.
    </P
><P
>&#13;     <TT
CLASS="parameter"
><I
>options</I
></TT
> holds additional flags set
     by the streams API. It can hold one or more of the following
     values OR'd together.
     <DIV
CLASS="informaltable"
><A
NAME="AEN88702"
></A
><P
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><THEAD
><TR
><TH
ALIGN="LEFT"
VALIGN="MIDDLE"
>Flag</TH
><TH
ALIGN="LEFT"
VALIGN="MIDDLE"
>Description</TH
></TR
></THEAD
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="MIDDLE"
>STREAM_USE_PATH</TD
><TD
ALIGN="LEFT"
VALIGN="MIDDLE"
>If <TT
CLASS="parameter"
><I
>path</I
></TT
> is relative, search
          for the resource using the include_path.
         </TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="MIDDLE"
>STREAM_REPORT_ERRORS</TD
><TD
ALIGN="LEFT"
VALIGN="MIDDLE"
>If this flag is set, you are responsible for raising
          errors using <A
HREF="function.trigger-error.html"
><B
CLASS="function"
>trigger_error()</B
></A
> during
          opening of the stream.  If this flag is not set, you
          should not raise any errors.
         </TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
>
    </P
><P
>&#13;     If the <TT
CLASS="parameter"
><I
>path</I
></TT
> is opened successfully,
     and STREAM_USE_PATH is set in <TT
CLASS="parameter"
><I
>options</I
></TT
>,
     you should set <TT
CLASS="parameter"
><I
>opened_path</I
></TT
> to the full
     path of the file/resource that was actually opened.
    </P
><P
>&#13;     If the requested resource was opened successfully, you should
     return <TT
CLASS="constant"
><B
>TRUE</B
></TT
>, otherwise you should return <TT
CLASS="constant"
><B
>FALSE</B
></TT
>
    </P
>void <B
CLASS="methodname"
>stream_close</B
> ( void )<BR
></BR
><P
>&#13;     This method is called when the stream is closed, using
     <A
HREF="function.fclose.html"
><B
CLASS="function"
>fclose()</B
></A
>.  You must release any resources
     that were locked or allocated by the stream.
    </P
>string <B
CLASS="methodname"
>stream_read</B
> ( int count)<BR
></BR
><P
>&#13;     This method is called in response to <A
HREF="function.fread.html"
><B
CLASS="function"
>fread()</B
></A
>
     and <A
HREF="function.fgets.html"
><B
CLASS="function"
>fgets()</B
></A
> calls on the stream.  You
     must return up-to <TT
CLASS="parameter"
><I
>count</I
></TT
> bytes of data
     from the current read/write position as a string.
     If there are less than <TT
CLASS="parameter"
><I
>count</I
></TT
>
     bytes available, return as many as are available.  If no
     more data is available, return either <TT
CLASS="constant"
><B
>FALSE</B
></TT
> or an
     empty string.
     You must also update the read/write position of the stream
     by the number of bytes that were successfully read.
    </P
>int <B
CLASS="methodname"
>stream_write</B
> ( string data)<BR
></BR
><P
>&#13;     This method is called in response to <A
HREF="function.fwrite.html"
><B
CLASS="function"
>fwrite()</B
></A
>
     calls on the stream.  You should store <TT
CLASS="parameter"
><I
>data</I
></TT
>
     into the underlying storage used by your stream.  If there is not
     enough room, try to store as many bytes as possible.
     You should return the number of bytes that were successfully
     stored in the stream, or 0 if none could be stored.
     You must also update the read/write position of the stream
     by the number of bytes that were successfully written.
    </P
>boolean <B
CLASS="methodname"
>stream_eof</B
> ( void )<BR
></BR
><P
>&#13;     This method is called in response to <A
HREF="function.feof.html"
><B
CLASS="function"
>feof()</B
></A
>
     calls on the stream.  You should return <TT
CLASS="constant"
><B
>TRUE</B
></TT
> if the read/write
     position is at the end of the stream and if no more data is available
     to be read, or <TT
CLASS="constant"
><B
>FALSE</B
></TT
> otherwise.
    </P
>int <B
CLASS="methodname"
>stream_tell</B
> ( void )<BR
></BR
><P
>&#13;     This method is called in response to <A
HREF="function.ftell.html"
><B
CLASS="function"
>ftell()</B
></A
>
     calls on the stream.  You should return the current read/write
     position of the stream.
    </P
>boolean <B
CLASS="methodname"
>stream_seek</B
> ( int offset, int whence)<BR
></BR
><P
>&#13;     This method is called in response to <A
HREF="function.fseek.html"
><B
CLASS="function"
>fseek()</B
></A
>
     calls on the stream.  You should update the read/write position
     of the stream according to <TT
CLASS="parameter"
><I
>offset</I
></TT
> and
     <TT
CLASS="parameter"
><I
>whence</I
></TT
>.  See <A
HREF="function.fseek.html"
><B
CLASS="function"
>fseek()</B
></A
>
     for more information about these parameters.
     Return <TT
CLASS="constant"
><B
>TRUE</B
></TT
> if the position was updated, <TT
CLASS="constant"
><B
>FALSE</B
></TT
> otherwise.
    </P
>boolean <B
CLASS="methodname"
>stream_flush</B
> ( void )<BR
></BR
><P
>&#13;     This method is called in response to <A
HREF="function.fflush.html"
><B
CLASS="function"
>fflush()</B
></A
>
     calls on the stream.  If you have cached data in your stream
     but not yet stored it into the underlying storage, you should
     do so now.
     Return <TT
CLASS="constant"
><B
>TRUE</B
></TT
> if the cached data was successfully stored (or
     if there was no data to store), or <TT
CLASS="constant"
><B
>FALSE</B
></TT
> if the data could
     not be stored.
    </P
><P
>&#13;     The example below implements a var:// protocol handler that
     allows read/write access to a named global variable using
     standard filesystem stream functions such as <A
HREF="function.fread.html"
><B
CLASS="function"
>fread()</B
></A
>.
     The var:// protocol implemented below, given the url
     "var://foo" will read/write data to/from $GLOBALS["foo"].

     <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN88799"
></A
><P
><B
>Example 1. A Stream for reading/writing global variables</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><PRE
CLASS="php"
>class VariableStream {
    var $position;
    var $varname;
   
    function stream_open($path, $mode, $options, &#38;$opened_path)
    {
        $url = parse_url($path);
        $this-&#62;varname = $url["host"];
        $this-&#62;position = 0;
        
        return true;
    }

    function stream_read($count)
    {
        $ret = substr($GLOBALS[$this-&#62;varname], $this-&#62;position, $count);
        $this-&#62;position += strlen($ret);
        return $ret;
    }

    function stream_write($data)
    {
        $left = substr($GLOBALS[$this-&#62;varname], 0, $this-&#62;position);
        $right = substr($GLOBALS[$this-&#62;varname], $this-&#62;position + strlen($data));
        $GLOBALS[$this-&#62;varname] = $left . $data . $right;
        $this-&#62;position += strlen($data);
        return strlen($data);
    }

    function stream_tell()
    {
        return $this-&#62;position;
    }

    function stream_eof()
    {
        return $this-&#62;position &#62;= strlen($GLOBALS[$this-&#62;varname]);
    }

    function stream_seek($offset, $whence)
    {
        switch($whence) {
            case SEEK_SET:
                if ($offset &#60; strlen($GLOBALS[$this-&#62;varname]) &#38;&#38; $offset &#62;= 0) {
                     $this-&#62;position = $offset;
                     return true;
                } else {
                     return false;
                }
                break;
                
            case SEEK_CUR:
                if ($offset &#62;= 0) {
                     $this-&#62;position += $offset;
                     return true;
                } else {
                     return false;
                }
                break;
                
            case SEEK_END:
                if (strlen($GLOBALS[$this-&#62;varname]) + $offset &#62;= 0) {
                     $this-&#62;position = strlen($GLOBALS[$this-&#62;varname]) + $offset;
                     return true;
                } else {
                     return false;
                }
                break;
                
            default:
                return false;
        }
    }
}

stream_register_wrapper("var", "VariableStream")
    or die("Failed to register protocol");

$myvar = "";
    
$fp = fopen("var://myvar", "r+");

fwrite($fp, "line1\n");
fwrite($fp, "line2\n");
fwrite($fp, "line3\n");

rewind($fp);
while(!feof($fp)) {
    echo fgets($fp);
}
fclose($fp);
var_dump($myvar);</PRE
></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
    </P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="function.stream-register-filter.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="function.stream-select.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>stream_register_filter</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="ref.stream.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>stream_select</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>