<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Example class registered as stream wrapper</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="stream.examples.html">Examples</a></div> <div class="next" style="text-align: right; float: right;"><a href="class.php-user-filter.html">php_user_filter</a></div> <div class="up"><a href="stream.examples.html">Examples</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="stream.streamwrapper.example-1" class="section"> <h2 class="title">Example class registered as stream wrapper</h2> <p class="para"> 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 <span class="function"><a href="function.fread.html" class="function">fread()</a></span>. The var:// protocol implemented below, given the URL "var://foo" will read/write data to/from $GLOBALS["foo"]. </p> <p class="para"> <div class="example" id="example-4007"> <p><strong>Example #1 A Stream for reading/writing global variables</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br /><br /></span><span style="color: #007700">class </span><span style="color: #0000BB">VariableStream </span><span style="color: #007700">{<br /> var </span><span style="color: #0000BB">$position</span><span style="color: #007700">;<br /> var </span><span style="color: #0000BB">$varname</span><span style="color: #007700">;<br /><br /> function </span><span style="color: #0000BB">stream_open</span><span style="color: #007700">(</span><span style="color: #0000BB">$path</span><span style="color: #007700">, </span><span style="color: #0000BB">$mode</span><span style="color: #007700">, </span><span style="color: #0000BB">$options</span><span style="color: #007700">, &</span><span style="color: #0000BB">$opened_path</span><span style="color: #007700">)<br /> {<br /> </span><span style="color: #0000BB">$url </span><span style="color: #007700">= </span><span style="color: #0000BB">parse_url</span><span style="color: #007700">(</span><span style="color: #0000BB">$path</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname </span><span style="color: #007700">= </span><span style="color: #0000BB">$url</span><span style="color: #007700">[</span><span style="color: #DD0000">"host"</span><span style="color: #007700">];<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">= </span><span style="color: #0000BB">0</span><span style="color: #007700">;<br /><br /> return </span><span style="color: #0000BB">true</span><span style="color: #007700">;<br /> }<br /><br /> function </span><span style="color: #0000BB">stream_read</span><span style="color: #007700">(</span><span style="color: #0000BB">$count</span><span style="color: #007700">)<br /> {<br /> </span><span style="color: #0000BB">$ret </span><span style="color: #007700">= </span><span style="color: #0000BB">substr</span><span style="color: #007700">(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">], </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position</span><span style="color: #007700">, </span><span style="color: #0000BB">$count</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">+= </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$ret</span><span style="color: #007700">);<br /> return </span><span style="color: #0000BB">$ret</span><span style="color: #007700">;<br /> }<br /><br /> function </span><span style="color: #0000BB">stream_write</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">)<br /> {<br /> </span><span style="color: #0000BB">$left </span><span style="color: #007700">= </span><span style="color: #0000BB">substr</span><span style="color: #007700">(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">], </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$right </span><span style="color: #007700">= </span><span style="color: #0000BB">substr</span><span style="color: #007700">(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">], </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">+ </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">));<br /> </span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">] = </span><span style="color: #0000BB">$left </span><span style="color: #007700">. </span><span style="color: #0000BB">$data </span><span style="color: #007700">. </span><span style="color: #0000BB">$right</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">+= </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">);<br /> return </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">);<br /> }<br /><br /> function </span><span style="color: #0000BB">stream_tell</span><span style="color: #007700">()<br /> {<br /> return </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position</span><span style="color: #007700">;<br /> }<br /><br /> function </span><span style="color: #0000BB">stream_eof</span><span style="color: #007700">()<br /> {<br /> return </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">>= </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">]);<br /> }<br /><br /> function </span><span style="color: #0000BB">stream_seek</span><span style="color: #007700">(</span><span style="color: #0000BB">$offset</span><span style="color: #007700">, </span><span style="color: #0000BB">$whence</span><span style="color: #007700">)<br /> {<br /> switch (</span><span style="color: #0000BB">$whence</span><span style="color: #007700">) {<br /> case </span><span style="color: #0000BB">SEEK_SET</span><span style="color: #007700">:<br /> if (</span><span style="color: #0000BB">$offset </span><span style="color: #007700">< </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">]) && </span><span style="color: #0000BB">$offset </span><span style="color: #007700">>= </span><span style="color: #0000BB">0</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">= </span><span style="color: #0000BB">$offset</span><span style="color: #007700">;<br /> return </span><span style="color: #0000BB">true</span><span style="color: #007700">;<br /> } else {<br /> return </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /> }<br /> break;<br /><br /> case </span><span style="color: #0000BB">SEEK_CUR</span><span style="color: #007700">:<br /> if (</span><span style="color: #0000BB">$offset </span><span style="color: #007700">>= </span><span style="color: #0000BB">0</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">+= </span><span style="color: #0000BB">$offset</span><span style="color: #007700">;<br /> return </span><span style="color: #0000BB">true</span><span style="color: #007700">;<br /> } else {<br /> return </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /> }<br /> break;<br /><br /> case </span><span style="color: #0000BB">SEEK_END</span><span style="color: #007700">:<br /> if (</span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">]) + </span><span style="color: #0000BB">$offset </span><span style="color: #007700">>= </span><span style="color: #0000BB">0</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">position </span><span style="color: #007700">= </span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">varname</span><span style="color: #007700">]) + </span><span style="color: #0000BB">$offset</span><span style="color: #007700">;<br /> return </span><span style="color: #0000BB">true</span><span style="color: #007700">;<br /> } else {<br /> return </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /> }<br /> break;<br /><br /> default:<br /> return </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /> }<br /> }<br /><br /> function </span><span style="color: #0000BB">stream_metadata</span><span style="color: #007700">(</span><span style="color: #0000BB">$path</span><span style="color: #007700">, </span><span style="color: #0000BB">$option</span><span style="color: #007700">, </span><span style="color: #0000BB">$var</span><span style="color: #007700">) <br /> {<br /> if(</span><span style="color: #0000BB">$option </span><span style="color: #007700">== </span><span style="color: #0000BB">STREAM_META_TOUCH</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">$url </span><span style="color: #007700">= </span><span style="color: #0000BB">parse_url</span><span style="color: #007700">(</span><span style="color: #0000BB">$path</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$varname </span><span style="color: #007700">= </span><span style="color: #0000BB">$url</span><span style="color: #007700">[</span><span style="color: #DD0000">"host"</span><span style="color: #007700">];<br /> if(!isset(</span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$varname</span><span style="color: #007700">])) {<br /> </span><span style="color: #0000BB">$GLOBALS</span><span style="color: #007700">[</span><span style="color: #0000BB">$varname</span><span style="color: #007700">] = </span><span style="color: #DD0000">''</span><span style="color: #007700">;<br /> }<br /> return </span><span style="color: #0000BB">true</span><span style="color: #007700">;<br /> }<br /> return </span><span style="color: #0000BB">false</span><span style="color: #007700">;<br /> }<br />}<br /><br /></span><span style="color: #0000BB">stream_wrapper_register</span><span style="color: #007700">(</span><span style="color: #DD0000">"var"</span><span style="color: #007700">, </span><span style="color: #DD0000">"VariableStream"</span><span style="color: #007700">)<br /> or die(</span><span style="color: #DD0000">"Failed to register protocol"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$myvar </span><span style="color: #007700">= </span><span style="color: #DD0000">""</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$fp </span><span style="color: #007700">= </span><span style="color: #0000BB">fopen</span><span style="color: #007700">(</span><span style="color: #DD0000">"var://myvar"</span><span style="color: #007700">, </span><span style="color: #DD0000">"r+"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">fwrite</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">, </span><span style="color: #DD0000">"line1\n"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">fwrite</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">, </span><span style="color: #DD0000">"line2\n"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">fwrite</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">, </span><span style="color: #DD0000">"line3\n"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">rewind</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">);<br />while (!</span><span style="color: #0000BB">feof</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #0000BB">fgets</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">);<br />}<br /></span><span style="color: #0000BB">fclose</span><span style="color: #007700">(</span><span style="color: #0000BB">$fp</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$myvar</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> <div class="example-contents"><p>The above example will output:</p></div> <div class="example-contents screen"> <div class="cdata"><pre> line1 line2 line3 string(18) "line1 line2 line3 " </pre></div> </div> </div> </p> </div><hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="stream.examples.html">Examples</a></div> <div class="next" style="text-align: right; float: right;"><a href="class.php-user-filter.html">php_user_filter</a></div> <div class="up"><a href="stream.examples.html">Examples</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div></body></html>