Simple example of php implementing template engine function

本文实例讲述了PHP实现简单的模板引擎功能。分享给大家供大家参考，具体如下：

php web开发中广泛采取mvc的设计模式，controller传递给view层的数据，必须通过模板引擎才能解析出来。实现一个简单的仅仅包含if，foreach标签，解析$foo变量的模板引擎。

编写template模板类和compiler编译类。代码如下：

<?php
namespace foo\base;
use foo\base\Object;
use foo\base\Compiler;
/**
* 
*/
class Template extends Object
{
  private $_config = [
    &#39;suffix&#39; => &#39;.php&#39;,//文件后缀名
    &#39;templateDir&#39; => &#39;../views/&#39;,//模板所在文件夹
    &#39;compileDir&#39; => &#39;../runtime/cache/views/&#39;,//编译后存放的目录
    &#39;suffixCompile&#39; => &#39;.php&#39;,//编译后文件后缀
    &#39;isReCacheHtml&#39; => false,//是否需要重新编译成静态html文件
    &#39;isSupportPhp&#39; => true,//是否支持php的语法
    &#39;cacheTime&#39; => 0,//缓存时间,单位秒
  ];
  private $_file;//带编译模板文件
  private $_valueMap = [];//键值对
  private $_compiler;//编译器
  public function __construct($compiler, $config = [])
  {
    $this->_compiler = $compiler;
    $this->_config = array_merge($this->_config, $config);
  }
  /**
   * [assign 存储控制器分配的键值]
   * @param [type] $values [键值对集合]
   * @return [type]     [description]
   */
  public function assign($values)
  {
    if (is_array($values)) {
      $this->_valueMap = $values;
    } else {
      throw new \Exception(&#39;控制器分配给视图的值必须为数组!&#39;);
    }
    return $this;
  }
  /**
   * [show 展现视图]
   * @param [type] $file [带编译缓存的文件]
   * @return [type]    [description]
   */
  public function show($file)
  {
    $this->_file = $file;
    if (!is_file($this->path())) {
      throw new \Exception(&#39;模板文件&#39;. $file . &#39;不存在!&#39;);
    }
    $compileFile = $this->_config[&#39;compileDir&#39;] . md5($file) . $this->_config[&#39;suffixCompile&#39;];
    $cacheFile = $this->_config[&#39;compileDir&#39;] . md5($file) . &#39;.html&#39;;
    //编译后文件不存在或者缓存时间已到期,重新编译,重新生成html静态缓存
    if (!is_file($compileFile) || $this->isRecompile($compileFile)) {
      $this->_compiler->compile($this->path(), $compileFile, $this->_valueMap);
      $this->_config[&#39;isReCacheHtml&#39;] = true;
      if ($this->isSupportPhp()) {
        extract($this->_valueMap, EXTR_OVERWRITE);//从数组中将变量导入到当前的符号表
      }
    }
    if ($this->isReCacheHtml()) {
      ob_start();
      ob_clean();
      include($compileFile);
      file_put_contents($cacheFile, ob_get_contents());
      ob_end_flush();
    } else {
      readfile($cacheFile);
    }
  }
  /**
   * [isRecompile 根据缓存时间判断是否需要重新编译]
   * @param [type] $compileFile [编译后的文件]
   * @return boolean       [description]
   */
  private function isRecompile($compileFile)
  {
    return time() - filemtime($compileFile) > $this->_config[&#39;cacheTime&#39;];
  }
  /**
   * [isReCacheHtml 是否需要重新缓存静态html文件]
   * @return boolean [description]
   */
  private function isReCacheHtml()
  {
    return $this->_config[&#39;isReCacheHtml&#39;];
  }
  /**
   * [isSupportPhp 是否支持php语法]
   * @return boolean [description]
   */
  private function isSupportPhp()
  {
    return $this->_config[&#39;isSupportPhp&#39;];
  }
  /**
   * [path 获得模板文件路径]
   * @return [type] [description]
   */
  private function path()
  {
    return $this->_config[&#39;templateDir&#39;] . $this->_file . $this->_config[&#39;suffix&#39;];
  }
}

<?php
namespace foo\base;
use foo\base\Object;
/**
* 
*/
class Compiler extends Object
{
  private $_content;
  private $_valueMap = [];
  private $_patten = [
    &#39;#\{\\$([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)\}#&#39;,
    &#39;#\{if (.*?)\}#&#39;,
    &#39;#\{(else if|elseif) (.*?)\}#&#39;,
    &#39;#\{else\}#&#39;,
    &#39;#\{foreach \\$([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)}#&#39;,
    &#39;#\{\/(foreach|if)}#&#39;,
    &#39;#\{\\^(k|v)\}#&#39;,
  ];
  private $_translation = [
    "<?php echo \$this->_valueMap[&#39;\\1&#39;]; ?>",
    &#39;<?php if (\\1) {?>&#39;,
    &#39;<?php } else if (\\2) {?>&#39;,
    &#39;<?php }else {?>&#39;,
    "<?php foreach (\$this->_valueMap[&#39;\\1&#39;] as \$k => \$v) {?>",
    &#39;<?php }?>&#39;,
    &#39;<?php echo \$\\1?>&#39;
  ];
  /**
   * [compile 编译模板文件]
   * @param [type] $source  [模板文件]
   * @param [type] $destFile [编译后文件]
   * @param [type] $values  [键值对]
   * @return [type]      [description]
   */
  public function compile($source, $destFile, $values)
  {
    $this->_content = file_get_contents($source);
    $this->_valueMap = $values;
    if (strpos($this->_content, &#39;{$&#39;) !== false) {
      $this->_content = preg_replace($this->_patten, $this->_translation, $this->_content);
    }
    file_put_contents($destFile, $this->_content);
  }
}

我们的控制器就可以调用template中的assign方法进行赋值，show方法进行模板编译了。

/**
* [render 渲染模板文件]
* @param [type] $file      [待编译的文件]
* @param [type] $values     [键值对]
* @param array $templateConfig [编译配置]
* @return [type]         [description]
*/
protected function render($file, $values, $templateConfig = [])
{
    $di = Container::getInstance();
    //依赖注入实例化对象
    $di->template = function () use ($di, $templateConfig) {
      $di->compiler = 'foo\base\Compiler';
      $compiler = $di->compiler;
      return new \foo\base\Template($compiler, $templateConfig);
    };
    $di->template->assign($values)->show($file);
}

Container类如下：

<?php
namespace foo\base;
use foo\base\Object;
class Container extends Object
{
  private static $_instance;
  private $s = [];
  public static $instances = [];
  public static function getInstance()
  {
    if (!(self::$_instance instanceof self)) {
      self::$_instance = new self();
    }
    return self::$_instance;
  }
  private function __construct(){}
  private function __clone(){}
  public function __set($k, $c)
  {
    $this->s[$k] = $c;
  }
  public function __get($k)
  {
    return $this->build($this->s[$k]);
  }
  /**
   * 自动绑定（Autowiring）自动解析（Automatic Resolution）
   *
   * @param string $className
   * @return object
   * @throws Exception
   */
  public function build($className)
  {   
    // 如果是闭包函数（closures）
    if ($className instanceof \Closure) {
      // 执行闭包函数
      return $className($this);
    }
    if (isset(self::$instances[$className])) {
      return self::$instances[$className];
    }
    /** @var ReflectionClass $reflector */
    $reflector = new \ReflectionClass($className);
    // 检查类是否可实例化, 排除抽象类abstract和对象接口interface
    if (!$reflector->isInstantiable()) {
      throw new \Exception($reflector . &#39;: 不能实例化该类!&#39;);
    }
    /** @var ReflectionMethod $constructor 获取类的构造函数 */
    $constructor = $reflector->getConstructor();
    // 若无构造函数，直接实例化并返回
    if (is_null($constructor)) {
      return new $className;
    }
    // 取构造函数参数,通过 ReflectionParameter 数组返回参数列表
    $parameters = $constructor->getParameters();
    // 递归解析构造函数的参数
    $dependencies = $this->getDependencies($parameters);
    // 创建一个类的新实例，给出的参数将传递到类的构造函数。
    $obj = $reflector->newInstanceArgs($dependencies);
    self::$instances[$className] = $obj;
    return $obj;
  }
  /**
   * @param array $parameters
   * @return array
   * @throws Exception
   */
  public function getDependencies($parameters)
  {
    $dependencies = [];
    /** @var ReflectionParameter $parameter */
    foreach ($parameters as $parameter) {
      /** @var ReflectionClass $dependency */
      $dependency = $parameter->getClass();
      if (is_null($dependency)) {
        // 是变量,有默认值则设置默认值
        $dependencies[] = $this->resolveNonClass($parameter);
      } else {
        // 是一个类，递归解析
        $dependencies[] = $this->build($dependency->name);
      }
    }
    return $dependencies;
  }
  /**
   * @param ReflectionParameter $parameter
   * @return mixed
   * @throws Exception
   */
  public function resolveNonClass($parameter)
  {
    // 有默认值则返回默认值
    if ($parameter->isDefaultValueAvailable()) {
      return $parameter->getDefaultValue();
    }
    throw new \Exception(&#39;I have no idea what to do here.&#39;);
  }
}

要想以键值对的方式访问对象的属性必须实现ArrayAccess接口的四个方法，

Object基类代码如下：

public function offsetExists($offset) 
{
    return array_key_exists($offset, get_object_vars($this));
}
public function offsetUnset($key) 
{
    if (array_key_exists($key, get_object_vars($this)) ) {
      unset($this->{$key});
    }
}
public function offsetSet($offset, $value) 
{
    $this->{$offset} = $value;
}
public function offsetGet($var) 
{
    return $this->$var;
}

在某一控制器中就可以调用父类Controller的render方法啦

复制代码 代码如下:

$this->render('test\index', ['name' => 'tom', 'age' => 20, 'friends' => ['jack', 'rose']], ['cacheTime' => 10]);

编写视图模板文件'test\index':

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>
  <p>展示模板文件视图</p> 
  <p>{$name}</p>
  <p>{$age}</p>
  <?php echo ++$age;?>
  {if $age > 18}
    <p>已成年</p>
  {else if $age < 10}
    <p>小毛孩</p>
  {/if}
  {foreach $friends} 
   <p>{^v} </p>
  {/foreach}
</body>
</html>

至此，一个简单的模板编译引擎就写好了。

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