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>Cache Handler Function</TITLE
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CLASS="sect1"
><H1
CLASS="sect1"
><A
NAME="section.template.cache.handler.func"
></A
>Cache Handler Function</H1
><P
> As an alternative to using the default file-based caching mechanism, you
can specify a custom cache handling function that will be used to
<TT
CLASS="literal"
>read</TT
>, <TT
CLASS="literal"
>write</TT
> and
<TT
CLASS="literal"
>clear</TT
> cached files.
</P
><P
> Create a function in your application that Smarty will use as a
cache handler. Set the name of it in the
<A
HREF="variable.cache.handler.func.html"
> <TT
CLASS="parameter"
><I
>$cache_handler_func</I
></TT
></A
>
class variable. Smarty will now use this to handle cached data.
</P
><P
></P
><UL
><LI
><P
> The first argument is the action, which will be one of
<TT
CLASS="literal"
>read</TT
>, <TT
CLASS="literal"
>write</TT
> and
<TT
CLASS="literal"
>clear</TT
>.
</P
></LI
><LI
><P
> The second parameter is the Smarty object.
</P
></LI
><LI
><P
>The third parameter
is the cached content. Upon a <TT
CLASS="literal"
>write</TT
>, Smarty passes the
cached content in these parameters. Upon a <TT
CLASS="literal"
>read</TT
>,
Smarty expects your function to accept this parameter by reference and
populate it with the cached data. Upon a <TT
CLASS="literal"
>clear</TT
>, pass a
dummy variable here since it is not used.
</P
></LI
><LI
><P
> The fourth parameter is the <TT
CLASS="parameter"
><I
>name</I
></TT
> of the template
file, needed for read/write.
</P
></LI
><LI
><P
> The fifth parameter is the optional <TT
CLASS="parameter"
><I
>$cache_id</I
></TT
>.
</P
></LI
><LI
><P
> The sixth is the optional <A
HREF="variable.compile.id.html"
> <TT
CLASS="parameter"
><I
>$compile_id</I
></TT
></A
>.
</P
></LI
><LI
><P
> The seventh and last parameter <TT
CLASS="parameter"
><I
>$exp_time</I
></TT
>
was added in Smarty-2.6.0.
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></A
><P
><B
>Example 15-5. Example using MySQL as a cache source</B
></P
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><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/**************************************************<br />example usage:<br /><br />include('Smarty.class.php');<br />include('mysql_cache_handler.php');<br /><br />$smarty = new Smarty;<br />$smarty->cache_handler_func = 'mysql_cache_handler';<br /><br />$smarty->display('index.tpl');<br /><br /><br />mysql database is expected in this format:<br /><br />create database SMARTY_CACHE;<br /><br />create table CACHE_PAGES(<br />CacheID char(32) PRIMARY KEY,<br />CacheContents MEDIUMTEXT NOT NULL<br />);<br /><br />**************************************************/<br /><br /></span><span style="color: #007700">function </span><span style="color: #0000BB">mysql_cache_handler</span><span style="color: #007700">(</span><span style="color: #0000BB">$action</span><span style="color: #007700">, &</span><span style="color: #0000BB">$smarty_obj</span><span style="color: #007700">, &</span><span style="color: #0000BB">$cache_content</span><span style="color: #007700">, </span><span style="color: #0000BB">$tpl_file</span><span style="color: #007700">=</span><span style="color: #0000BB">null</span><span style="color: #007700">, </span><span style="color: #0000BB">$cache_id</span><span style="color: #007700">=</span><span style="color: #0000BB">null</span><span style="color: #007700">, </span><span style="color: #0000BB">$compile_id</span><span style="color: #007700">=</span><span style="color: #0000BB">null</span><span style="color: #007700">, </span><span style="color: #0000BB">$exp_time</span><span style="color: #007700">=</span><span style="color: #0000BB">null</span><span style="color: #007700">)<br />{<br /> </span><span style="color: #FF8000">// set db host, user and pass here<br /> </span><span style="color: #0000BB">$db_host </span><span style="color: #007700">= </span><span style="color: #DD0000">'localhost'</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$db_user </span><span style="color: #007700">= </span><span style="color: #DD0000">'myuser'</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$db_pass </span><span style="color: #007700">= </span><span style="color: #DD0000">'mypass'</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$db_name </span><span style="color: #007700">= </span><span style="color: #DD0000">'SMARTY_CACHE'</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$use_gzip </span><span style="color: #007700">= </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /><br /> </span><span style="color: #FF8000">// create unique cache id<br /> </span><span style="color: #0000BB">$CacheID </span><span style="color: #007700">= </span><span style="color: #0000BB">md5</span><span style="color: #007700">(</span><span style="color: #0000BB">$tpl_file</span><span style="color: #007700">.</span><span style="color: #0000BB">$cache_id</span><span style="color: #007700">.</span><span style="color: #0000BB">$compile_id</span><span style="color: #007700">);<br /><br /> if(! </span><span style="color: #0000BB">$link </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_pconnect</span><span style="color: #007700">(</span><span style="color: #0000BB">$db_host</span><span style="color: #007700">, </span><span style="color: #0000BB">$db_user</span><span style="color: #007700">, </span><span style="color: #0000BB">$db_pass</span><span style="color: #007700">)) {<br /> </span><span style="color: #0000BB">$smarty_obj</span><span style="color: #007700">-></span><span style="color: #0000BB">_trigger_error_msg</span><span style="color: #007700">(</span><span style="color: #DD0000">'cache_handler: could not connect to database'</span><span style="color: #007700">);<br /> return </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /> }<br /> </span><span style="color: #0000BB">mysql_select_db</span><span style="color: #007700">(</span><span style="color: #0000BB">$db_name</span><span style="color: #007700">);<br /><br /> switch (</span><span style="color: #0000BB">$action</span><span style="color: #007700">) {<br /> case </span><span style="color: #DD0000">'read'</span><span style="color: #007700">:<br /> </span><span style="color: #FF8000">// read cache from database<br /> </span><span style="color: #0000BB">$results </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"select CacheContents from CACHE_PAGES where CacheID='$CacheID'"</span><span style="color: #007700">);<br /> if(!</span><span style="color: #0000BB">$results</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$smarty_obj</span><span style="color: #007700">-></span><span style="color: #0000BB">_trigger_error_msg</span><span style="color: #007700">(</span><span style="color: #DD0000">'cache_handler: query failed.'</span><span style="color: #007700">);<br /> }<br /> </span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_fetch_array</span><span style="color: #007700">(</span><span style="color: #0000BB">$results</span><span style="color: #007700">,</span><span style="color: #0000BB">MYSQL_ASSOC</span><span style="color: #007700">);<br /><br /> if(</span><span style="color: #0000BB">$use_gzip </span><span style="color: #007700">&& </span><span style="color: #0000BB">function_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">'gzuncompress'</span><span style="color: #007700">)) {<br /> </span><span style="color: #0000BB">$cache_content </span><span style="color: #007700">= </span><span style="color: #0000BB">gzuncompress</span><span style="color: #007700">(</span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #DD0000">'CacheContents'</span><span style="color: #007700">]);<br /> } else {<br /> </span><span style="color: #0000BB">$cache_content </span><span style="color: #007700">= </span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #DD0000">'CacheContents'</span><span style="color: #007700">];<br /> }<br /> </span><span style="color: #0000BB">$return </span><span style="color: #007700">= </span><span style="color: #0000BB">$results</span><span style="color: #007700">;<br /> break;<br /> case </span><span style="color: #DD0000">'write'</span><span style="color: #007700">:<br /> </span><span style="color: #FF8000">// save cache to database<br /><br /> </span><span style="color: #007700">if(</span><span style="color: #0000BB">$use_gzip </span><span style="color: #007700">&& </span><span style="color: #0000BB">function_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">"gzcompress"</span><span style="color: #007700">)) {<br /> </span><span style="color: #FF8000">// compress the contents for storage efficiency<br /> </span><span style="color: #0000BB">$contents </span><span style="color: #007700">= </span><span style="color: #0000BB">gzcompress</span><span style="color: #007700">(</span><span style="color: #0000BB">$cache_content</span><span style="color: #007700">);<br /> } else {<br /> </span><span style="color: #0000BB">$contents </span><span style="color: #007700">= </span><span style="color: #0000BB">$cache_content</span><span style="color: #007700">;<br /> }<br /> </span><span style="color: #0000BB">$results </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"replace into CACHE_PAGES values(<br /> '$CacheID',<br /> '"</span><span style="color: #007700">.</span><span style="color: #0000BB">addslashes</span><span style="color: #007700">(</span><span style="color: #0000BB">$contents</span><span style="color: #007700">).</span><span style="color: #DD0000">"')<br /> "</span><span style="color: #007700">);<br /> if(!</span><span style="color: #0000BB">$results</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$smarty_obj</span><span style="color: #007700">-></span><span style="color: #0000BB">_trigger_error_msg</span><span style="color: #007700">(</span><span style="color: #DD0000">'cache_handler: query failed.'</span><span style="color: #007700">);<br /> }<br /> </span><span style="color: #0000BB">$return </span><span style="color: #007700">= </span><span style="color: #0000BB">$results</span><span style="color: #007700">;<br /> break;<br /> case </span><span style="color: #DD0000">'clear'</span><span style="color: #007700">:<br /> </span><span style="color: #FF8000">// clear cache info<br /> </span><span style="color: #007700">if(empty(</span><span style="color: #0000BB">$cache_id</span><span style="color: #007700">) && empty(</span><span style="color: #0000BB">$compile_id</span><span style="color: #007700">) && empty(</span><span style="color: #0000BB">$tpl_file</span><span style="color: #007700">)) {<br /> </span><span style="color: #FF8000">// clear them all<br /> </span><span style="color: #0000BB">$results </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">'delete from CACHE_PAGES'</span><span style="color: #007700">);<br /> } else {<br /> </span><span style="color: #0000BB">$results </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"delete from CACHE_PAGES where CacheID='$CacheID'"</span><span style="color: #007700">);<br /> }<br /> if(!</span><span style="color: #0000BB">$results</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$smarty_obj</span><span style="color: #007700">-></span><span style="color: #0000BB">_trigger_error_msg</span><span style="color: #007700">(</span><span style="color: #DD0000">'cache_handler: query failed.'</span><span style="color: #007700">);<br /> }<br /> </span><span style="color: #0000BB">$return </span><span style="color: #007700">= </span><span style="color: #0000BB">$results</span><span style="color: #007700">;<br /> break;<br /> default:<br /> </span><span style="color: #FF8000">// error, unknown action<br /> </span><span style="color: #0000BB">$smarty_obj</span><span style="color: #007700">-></span><span style="color: #0000BB">_trigger_error_msg</span><span style="color: #007700">(</span><span style="color: #DD0000">"cache_handler: unknown action \"$action\""</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$return </span><span style="color: #007700">= </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /> break;<br /> }<br /> </span><span style="color: #0000BB">mysql_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">);<br /> return </span><span style="color: #0000BB">$return</span><span style="color: #007700">;<br /><br />}<br /><br /></span><span style="color: #0000BB">?></span>
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