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>session_set_save_handler</H1
><DIV
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><A
NAME="AEN208707"
></A
><P
> (PHP 4, PHP 5)</P
>session_set_save_handler --
Sets user-level session storage functions
</DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN208710"
></A
><H2
>Description</H2
>bool <B
CLASS="methodname"
>session_set_save_handler</B
> ( callback open, callback close, callback read, callback write, callback destroy, callback gc )<BR
></BR
><P
> <B
CLASS="function"
>session_set_save_handler()</B
> sets the user-level
session storage functions which are used for storing and
retrieving data associated with a session. This is most useful
when a storage method other than those supplied by PHP sessions
is preferred. i.e. Storing the session data in a local database.
如果成功则返回 <TT
CLASS="constant"
><B
>TRUE</B
></TT
>，失败则返回 <TT
CLASS="constant"
><B
>FALSE</B
></TT
>。
</P
><DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>
The "write" handler is not executed until after the output
stream is closed. Thus, output from debugging statements in the
"write" handler will never be seen in the browser. If debugging
output is necessary, it is suggested that the debug output be
written to a file instead.
</P
></BLOCKQUOTE
></DIV
><P
> The following example provides file based session
storage similar to the PHP sessions default save handler
<CODE
CLASS="parameter"
>files</CODE
>. This example could easily be
extended to cover database storage using your favorite PHP
supported database engine.
</P
><P
> Read function must return string value always to make save
handler work as expected. Return empty string if there is no data
to read. Return values from other handlers are converted to
boolean expression. <TT
CLASS="constant"
><B
>TRUE</B
></TT
> for success, <TT
CLASS="constant"
><B
>FALSE</B
></TT
> for failure.
</P
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><B
>警告</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
> Write and Close handlers are called after destructing objects since PHP
5.0.5. Thus destructors can use sessions but session handler can't use
objects. In prior versions, they were called in the opposite order. It
is possible to call <A
HREF="function.session-write-close.html"
><B
CLASS="function"
>session_write_close()</B
></A
> from the
destructor to solve this chicken and egg problem.
</P
></TD
></TR
></TABLE
></DIV
><P
> <TABLE
WIDTH="100%"
BORDER="0"
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CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN208748"
></A
><P
><B
>例 1.
<B
CLASS="function"
>session_set_save_handler()</B
> example
</B
></P
><TABLE
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><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br /></font><font color="#007700">function </font><font color="#0000BB">open</font><font color="#007700">(</font><font color="#0000BB">$save_path</font><font color="#007700">, </font><font color="#0000BB">$session_name</font><font color="#007700">) <br />{<br /> global </font><font color="#0000BB">$sess_save_path</font><font color="#007700">;<br /> <br /> </font><font color="#0000BB">$sess_save_path </font><font color="#007700">= </font><font color="#0000BB">$save_path</font><font color="#007700">;<br /> return(</font><font color="#0000BB">true</font><font color="#007700">);<br />}<br /><br />function </font><font color="#0000BB">close</font><font color="#007700">() <br />{<br /> return(</font><font color="#0000BB">true</font><font color="#007700">);<br />}<br /><br />function </font><font color="#0000BB">read</font><font color="#007700">(</font><font color="#0000BB">$id</font><font color="#007700">) <br />{<br /> global </font><font color="#0000BB">$sess_save_path</font><font color="#007700">;<br /> <br /> </font><font color="#0000BB">$sess_file </font><font color="#007700">= </font><font color="#DD0000">"$sess_save_path/sess_$id"</font><font color="#007700">;<br /> return (string) @</font><font color="#0000BB">file_get_contents</font><font color="#007700">(</font><font color="#0000BB">$sess_file</font><font color="#007700">);<br />}<br /><br />function </font><font color="#0000BB">write</font><font color="#007700">(</font><font color="#0000BB">$id</font><font color="#007700">, </font><font color="#0000BB">$sess_data</font><font color="#007700">) <br />{<br /> global </font><font color="#0000BB">$sess_save_path</font><font color="#007700">;<br /> <br /> </font><font color="#0000BB">$sess_file </font><font color="#007700">= </font><font color="#DD0000">"$sess_save_path/sess_$id"</font><font color="#007700">;<br /> if (</font><font color="#0000BB">$fp </font><font color="#007700">= @</font><font color="#0000BB">fopen</font><font color="#007700">(</font><font color="#0000BB">$sess_file</font><font color="#007700">, </font><font color="#DD0000">"w"</font><font color="#007700">)) {<br /> </font><font color="#0000BB">$return </font><font color="#007700">= </font><font color="#0000BB">fwrite</font><font color="#007700">(</font><font color="#0000BB">$fp</font><font color="#007700">, </font><font color="#0000BB">$sess_data</font><font color="#007700">);<br /> </font><font color="#0000BB">fclose</font><font color="#007700">(</font><font color="#0000BB">$fp</font><font color="#007700">);<br /> return </font><font color="#0000BB">$return</font><font color="#007700">;<br /> } else {<br /> return(</font><font color="#0000BB">false</font><font color="#007700">);<br /> }<br /><br />}<br /><br />function </font><font color="#0000BB">destroy</font><font color="#007700">(</font><font color="#0000BB">$id</font><font color="#007700">) <br />{<br /> global </font><font color="#0000BB">$sess_save_path</font><font color="#007700">;<br /> <br /> </font><font color="#0000BB">$sess_file </font><font color="#007700">= </font><font color="#DD0000">"$sess_save_path/sess_$id"</font><font color="#007700">;<br /> return(@</font><font color="#0000BB">unlink</font><font color="#007700">(</font><font color="#0000BB">$sess_file</font><font color="#007700">));<br />}<br /><br />function </font><font color="#0000BB">gc</font><font color="#007700">(</font><font color="#0000BB">$maxlifetime</font><font color="#007700">) <br />{<br /> global </font><font color="#0000BB">$sess_save_path</font><font color="#007700">;<br /> <br /> foreach (</font><font color="#0000BB">glob</font><font color="#007700">(</font><font color="#DD0000">"$sess_save_path/sess_*"</font><font color="#007700">) as </font><font color="#0000BB">$filename</font><font color="#007700">) {<br /> if (</font><font color="#0000BB">filemtime</font><font color="#007700">(</font><font color="#0000BB">$filename</font><font color="#007700">) + </font><font color="#0000BB">$maxlifetime </font><font color="#007700">< </font><font color="#0000BB">time</font><font color="#007700">()) {<br /> @</font><font color="#0000BB">unlink</font><font color="#007700">(</font><font color="#0000BB">$filename</font><font color="#007700">);<br /> }<br /> }<br /> return </font><font color="#0000BB">true</font><font color="#007700">;<br />}<br /><br /></font><font color="#0000BB">session_set_save_handler</font><font color="#007700">(</font><font color="#DD0000">"open"</font><font color="#007700">, </font><font color="#DD0000">"close"</font><font color="#007700">, </font><font color="#DD0000">"read"</font><font color="#007700">, </font><font color="#DD0000">"write"</font><font color="#007700">, </font><font color="#DD0000">"destroy"</font><font color="#007700">, </font><font color="#DD0000">"gc"</font><font color="#007700">);<br /><br /></font><font color="#0000BB">session_start</font><font color="#007700">();<br /><br /></font><font color="#FF8000">// proceed to use sessions normally<br /><br /></font><font color="#0000BB">?></font>
</font>
</code></TD
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>
</P
><P
> See also the <A
HREF="ref.session.html#ini.session.save-handler"
>session.save_handler</A
>
configuration directive.
</P
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