探讨PHP ereg()函数与正则表达式的匹配_PHP教程

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><span> ?php  </span></span></span></li>
<li>
<span>$</span><span class="attribute">username</span><span> = $_SERVER['REMOTE_USER'];  </span>
</li>
<li class="alt">
<span>$</span><span class="attribute">filename</span><span> = $_GET['file'];  </span>
</li>
<li><span>//对文件名进行过滤，以保证系统安全  </span></li>
<li class="alt"><span>if (!ereg('^[^./][^/]*$', $userfile))  </span></li>
<li><span>{  </span></li>
<li class="alt"><span>die('这不是一个非法的文件名！');  </span></li>
<li><span>}  </span></li>
<li class="alt"><span>//对用户名进行过滤  </span></li>
<li><span>if (!ereg('^[^./][^/]*$', $username))  </span></li>
<li class="alt"><span>{  </span></li>
<li><span>die('这不是一个无效的用户名');  </span></li>
<li class="alt"><span>}  </span></li>
<li><span>//通过安全过滤，拼合文件路径  </span></li>
<li class="alt">
<span>$</span><span class="attribute">thefile</span><span> = </span><span class="attribute-value">"/home/$username/$filename"</span><span>;  </span>
</li>
<li>
<span class="tag">?></span><span> </span>
</li>
</ol>