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PHP 模板引擎實作：編譯快取與標籤替換機制

編輯：PHP 綜合知識

設計理念

在效能與易用性間取得平衡：採用 HTML 編譯為 PHP 的方式，分離顯示邏輯與商業邏輯，支援美工使用 Dreamweaver 等視覺化工具編輯模板。

架構流程

1. 主程式 (index.php)

<?php
require('./template.php');
$tpl_prefix = 'default'; // 風格前綴
$tpl_index = 'index';    // 模板名稱

$tpl = new Template($tpl_prefix);

// 模擬資料
$cats = array(
    array('forum_id'=>'1', 'forum_cat_id'=>'0', 'forum_name'=>'PHP學習'),
    array('forum_id'=>'2', 'forum_cat_id'=>'0', 'forum_name'=>'MYSQL學習')
);
$forums = array(
    array('forum_id'=>'3', 'forum_cat_id'=>'1', 'forum_name'=>'PHP高級教程'),
    array('forum_id'=>'4', 'forum_cat_id'=>'1', 'forum_name'=>'PHP初級教程'),
    array('forum_id'=>'5', 'forum_cat_id'=>'2', 'forum_name'=>'MYSQL相關資料')
);

if ($cats) {
    if ($tpl->chk_cache($tpl_index)) { // 檢查是否需重新編譯
        $tpl->load_tpl($tpl_index);    // 載入 HTML 模板
        
        // 替換區塊標籤為 PHP 迴圈
        $tpl->assign_block("{block_cat}", "<?foreach(\$cats as \$cat) {?>");
        $tpl->assign_block("{/block_cat}", "<?}?>");
        $tpl->assign_block("{block_forum}", "<?foreach(\$forums as \$forum) {\nif(\$forum['forum_cat_id'] == \$cat['forum_id']) {?>");
        $tpl->assign_block("{/block_forum}", "<?}\n}?>");
        
        $tpl->write_cache($tpl_index); // 生成編譯後 PHP 檔
    }
}
include($tpl->parse_tpl($tpl_index)); // 包含編譯後檔案
?>

2. HTML 模板 (index.html)

{block_cat}
<table width="100%" border="0" cellspacing="1" cellpadding="1" bgcolor="#000000" align="center">
    <tr align="{=TR_ALING}" bgcolor="#FFFFFF">
        <td colspan="6"><span class="title"><b>{=$cat['forum_name']}</b></span></td>
    </tr>
{block_forum}
    <tr bgcolor="#FFFFFF">
        <td valign="top">{=$forum['forum_name']}</td>
    </tr>
{/block_forum}
</table>
<br>
{/block_cat}

3. 編譯後 PHP (default_index.php)

<?foreach($cats as $cat) {?>
<table width="100%" border="0" cellspacing="1" cellpadding="1" bgcolor="#000000" align="center">
    <tr align="<?=TR_ALING?>" bgcolor="#FFFFFF">
        <td colspan="6"><span class="title"><b><?=$cat['forum_name']?></b></span></td>
    </tr>
<?foreach($forums as $forum) {
if($forum['forum_cat_id'] == $cat['forum_id']) {?>
    <tr bgcolor="#FFFFFF">
        <td valign="top"><?=$forum['forum_name']?></td>
    </tr>
<?
}
}?>
</table>
<br>
<?}?>

Template 類別核心實作

class Template {
    var $template = '';
    var $tpl_path = '';
    var $tpl_prefix = '';
    var $cache_path = '';
    var $css_path = '';
    var $header_path = '';
    var $footer_path = '';

    function Template($root = 'default') {
        $this->tpl_prefix = $root;
        $this->tpl_path = './templates/' . $root . '/';
        $this->cache_path = './template_data/' . $this->tpl_prefix . '_';
        return true;
    }

    // 檢查快取是否過期
    function chk_cache($tpl_index) {
        $tpl_file = $this->tpl_path . $tpl_index . '.html';
        $cache_file = $this->cache_path . $tpl_index . '.php';
        if (!file_exists($cache_file)) return true;
        elseif (filemtime($tpl_file) > filemtime($cache_file)) return true;
        return false;
    }

    function parse_tpl($tpl_index, $message = '') {
        return $this->cache_path . $tpl_index . '.php';
    }

    function load_tpl($tpl_index) {
        $tpl_file = $this->tpl_path . $tpl_index . '.html';
        $fp = fopen($tpl_file, 'r');
        $this->template = fread($fp, filesize($tpl_file));
        fclose($fp);
    }

    function write_cache($tpl_index) {
        $cache_file = $this->cache_path . $tpl_index . '.php';
        
        // 變數顯示標籤 {=var} => 
        $this->template = preg_replace("/(\{=)(.+?)(\})/is", "<?=\\2?>", $this->template);
        
        // 語言包標籤 {lang key} => $lang['main']['key']
        $this->template = preg_replace("/\{lang +(.+?)\}/ies", "\$lang['main']['\\1']", $this->template);
        
        $fp = fopen($cache_file, 'w');
        flock($fp, 3);
        fwrite($fp, $this->template);
        fclose($fp);
    }

    function assign_block($search, $replace) {
        $this->template = str_replace($search, $replace, $this->template);
    }
}