Zend Framework routing mechanism code analysis, zendframework

This article analyzes the Zend Framework routing mechanism code. Share it with everyone for your reference, the details are as follows:

In the framework, the calling relationship of routing is:

1. Apache’s mod_rewrite module routes requests to the framework’s startup script, usually index.php;

2. The front-end controller Zend_Controller_Front distributes requests through the dispatch function;

3. The router Zend_Controller_Router_Rewrite processes routing through the route function. For the existing routing rules in the router, the match function is called on each route in the reverse order of the adding order (similar to a stack, last in first out) to check whether the request is consistent with the current one. The routing rules match. If they match, set the router's current route variable ($_currentRoute) to the matching route, and pass the parameters parsed by route to the Zend_Controller_Request_Http object. Complete the route setting here.

If no route is found, the framework will use the index action of the Index controller.

Analysis of function code in Zend_Controller_Router_Route:

1. Constructor

public function __construct($route, $defaults = array(), $reqs = array())
{
  $route = trim($route, $this->_urlDelimiter); //去掉規(guī)則首尾的url分隔符（默認是/）
  $this->_defaults = (array) $defaults; //默認值數組，以變量名為鍵
  $this->_requirements = (array) $reqs; //變量需要滿足的正則表達式，以變量名為鍵
  if ($route != '') {
   foreach (explode($this->_urlDelimiter, $route) as $pos => $part) {
    //把規(guī)則切分為一個數組
    if (substr($part, 0, 1) == $this->_urlVariable) {//如果是一個變量的定義
     $name = substr($part, 1); //獲取變量名
     //如果該變量定義了對應的正則表達式，則獲取該表達式，否則置為null
     $regex = (isset($reqs[$name]) ? $reqs[$name] : $this->_defaultRegex);
     //_parts數組包含了規(guī)則的各個部分，如果是變量的話，數組中有name元素
     $this->_parts[$pos] = array('name' => $name, 'regex' => $regex);
     //_vars包含了該規(guī)則中的所有變量的名字
     $this->_vars[] = $name;
    } else { //普通字符串
     $this->_parts[$pos] = array('regex' => $part);
     if ($part != '*') {
      $this->_staticCount++; //該規(guī)則的普通字符串的個數
     }
    }
   }
  }
}

2. Matching algorithm

public function match($path)
{
  $pathStaticCount = 0;
  $defaults = $this->_defaults; //默認值數組，數組元素的鍵值是變量名
   //默認值數組的一個拷貝，不過變量的值全部換成布爾值，其實這個值并沒有實際用處，下面程序僅僅
  //是通過判斷鍵值是否存在而確定是否包含一個變量，可能這么做是為了節(jié)省空間，不過要是這樣的話
  //不如直接使用 $this->_defaults了？
  if (count($defaults)) {
   $unique = array_combine(array_keys($defaults), array_fill(0, count($defaults), true));
  } else {
   $unique = array();
  }
  $path = trim($path, $this->_urlDelimiter); //傳入的path是已經去掉baseUrl的，這里確保去掉首尾的分隔符
  if ($path != '') {
   $path = explode($this->_urlDelimiter, $path);
   foreach ($path as $pos => $pathPart) {
    if (!isset($this->_parts[$pos])) {
     //把path根據url分隔符分割為數組后，把每一部分和規(guī)則的對應部分比較，如果path中存在，
     //而規(guī)則中不存在對應部分，那么該規(guī)則肯定不匹配，這里要注意$pos，是通過它把規(guī)則
     //和path的對應部分對應起來。
     return false;
    }
    if ($this->_parts[$pos]['regex'] == '*') {
      //如果規(guī)則的當前部分是通配符*，則把path的剩余部分解釋為url傳遞過來的變量，他們按照
     //“變量名/變量值”這樣的形式成對出現
     $parts = array_slice($path, $pos); //獲取path的剩余部分
     $this->_getWildcardData($parts, $unique);
     break;
    }
    $part = $this->_parts[$pos];
    $name = isset($part['name']) ? $part['name'] : null;
    $pathPart = urldecode($pathPart);//對傳過來的值進行解碼
    if ($name === null) {//普通字符串，和規(guī)則的對應部分比較是否相等即可
     if ($part['regex'] != $pathPart) {
      return false;
     }
    } elseif ($part['regex'] === null) {
      //如果是變量，但是沒有需要滿足的正則表達式，那么只有值不為空就可以了
     if (strlen($pathPart) == 0) {
      return false;
     }
    } else {//如果對該變量需要滿足一個正則表達式，那么這里進行驗證
     $regex = $this->_regexDelimiter . '^' . $part['regex'] . '$' . $this->_regexDelimiter . 'iu';
     if (!preg_match($regex, $pathPart)) {
      return false;
     }
    }
    if ($name !== null) {
     // 如果是一個變量，則設置變量的值
     $this->_values[$name] = $pathPart;
     $unique[$name] = true; //其實沒有必要設置，這個版本根本就沒有用它
    } else {
     //把普通字符串的匹配計數加1，因為規(guī)則中的普通字符串是必須在path中存在的，否則就是
     //匹配失敗
     $pathStaticCount++;
    }
   }
  }
   //$this->_values中保存的是分析獲取的變量，如果規(guī)則中存在‘*'，則$this->_params是獲取的
  //變量，否則是空數組，$this->_defaults是規(guī)則提供的默認變量值，這里用‘+'把三個數組相加
  //這樣的好處是如果后面的數組與前面的數組有相同的非整數的鍵值，后面的不會覆蓋前面的，這
  //與array_merge函數有區(qū)別，后者是會覆蓋的。也就是說，如果$this->_values 中已經有鍵controller
  //，那么$this->_defaults中的controller元素就被忽略，這樣就$this->_defaults中的默認值只有在path
  //中不存在的時候才會出現在返回值中。
  $return = $this->_values + $this->_params + $this->_defaults;
  // Check if all static mappings have been met
  if ($this->_staticCount != $pathStaticCount) {//規(guī)則的所有普通字符串必須在path中得到匹配
   return false;
  }
  // 解析完后，規(guī)則定義的所有變量也必須全部出現，否則視為不匹配
  foreach ($this->_vars as $var) {
   if (!array_key_exists($var, $return)) {
    return false;
   }
  }
  return $return;
}

Readers who are interested in more zend-related content can check out the special topics of this site: "Zend FrameWork Framework Introductory Tutorial", "php Excellent Development Framework Summary", "Yii Framework Introduction and Summary of Common Techniques", "ThinkPHP Introductory Tutorial" , "php object-oriented programming introductory tutorial", "php mysql database operation introductory tutorial" and "php common database operation skills summary"

I hope this article will be helpful to everyone’s PHP programming based on the Zend Framework framework.

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