YII 类库手册

public function __construct($route,$pattern)
{
    if(is_array($route))
    {
        foreach(array('urlSuffix', 'caseSensitive', 'defaultParams', 'matchValue', 'verb', 'parsingOnly') as $name)
        {
            if(isset($route[$name]))
                $this->$name=$route[$name];
        }
        if(isset($route['pattern']))
            $pattern=$route['pattern'];
        $route=$route[0];
    }
    $this->route=trim($route,'/');

    $tr2['/']=$tr['/']='\\/';

    if(strpos($route,'<')!==false && preg_match_all('/<(\w+)>/',$route,$matches2))
    {
        foreach($matches2[1] as $name)
            $this->references[$name]="<$name>";
    }

    $this->hasHostInfo=!strncasecmp($pattern,'http://',7) || !strncasecmp($pattern,'https://',8);

    if($this->verb!==null)
        $this->verb=preg_split('/[\s,]+/',strtoupper($this->verb),-1,PREG_SPLIT_NO_EMPTY);

    if(preg_match_all('/<(\w+):?(.*?)?>/',$pattern,$matches))
    {
        $tokens=array_combine($matches[1],$matches[2]);
        foreach($tokens as $name=>$value)
        {
            if($value==='')
                $value='[^\/]+';
            $tr["<$name>"]="(?P<$name>$value)";
            if(isset($this->references[$name]))
                $tr2["<$name>"]=$tr["<$name>"];
            else
                $this->params[$name]=$value;
        }
    }
    $p=rtrim($pattern,'*');
    $this->append=$p!==$pattern;
    $p=trim($p,'/');
    $this->template=preg_replace('/<(\w+):?.*?>/','<$1>',$p);
    $this->pattern='/^'.strtr($this->template,$tr).'\/';
    if($this->append)
        $this->pattern.='/u';
    else
        $this->pattern.='$/u';

    if($this->references!==array())
        $this->routePattern='/^'.strtr($this->route,$tr2).'$/u';

    if(YII_DEBUG && @preg_match($this->pattern,'test')===false)
        throw new CException(Yii::t('yii','The URL pattern "{pattern}" for route "{route}" is not a valid regular expression.',
            array('{route}'=>$route,'{pattern}'=>$pattern)));
}

public function createUrl($manager,$route,$params,$ampersand)
{
    if($this->parsingOnly)
        return false;

    if($manager->caseSensitive && $this->caseSensitive===null || $this->caseSensitive)
        $case='';
    else
        $case='i';

    $tr=array();
    if($route!==$this->route)
    {
        if($this->routePattern!==null && preg_match($this->routePattern.$case,$route,$matches))
        {
            foreach($this->references as $key=>$name)
                $tr[$name]=$matches[$key];
        }
        else
            return false;
    }

    foreach($this->defaultParams as $key=>$value)
    {
        if(isset($params[$key]))
        {
            if($params[$key]==$value)
                unset($params[$key]);
            else
                return false;
        }
    }

    foreach($this->params as $key=>$value)
        if(!isset($params[$key]))
            return false;

    if($manager->matchValue && $this->matchValue===null || $this->matchValue)
    {
        foreach($this->params as $key=>$value)
        {
            if(!preg_match('/'.$value.'/'.$case,$params[$key]))
                return false;
        }
    }

    foreach($this->params as $key=>$value)
    {
        $tr["<$key>"]=urlencode($params[$key]);
        unset($params[$key]);
    }

    $suffix=$this->urlSuffix===null ? $manager->urlSuffix : $this->urlSuffix;

    $url=strtr($this->template,$tr);

    if($this->hasHostInfo)
    {
        $hostInfo=Yii::app()->getRequest()->getHostInfo();
        if(stripos($url,$hostInfo)===0)
            $url=substr($url,strlen($hostInfo));
    }

    if(empty($params))
        return $url!=='' ? $url.$suffix : $url;

    if($this->append)
        $url.='/'.$manager->createPathInfo($params,'/','/').$suffix;
    else
    {
        if($url!=='')
            $url.=$suffix;
        $url.='?'.$manager->createPathInfo($params,'=',$ampersand);
    }

    return $url;
}

public function parseUrl($manager,$request,$pathInfo,$rawPathInfo)
{
    if($this->verb!==null && !in_array($request->getRequestType(), $this->verb, true))
        return false;

    if($manager->caseSensitive && $this->caseSensitive===null || $this->caseSensitive)
        $case='';
    else
        $case='i';

    if($this->urlSuffix!==null)
        $pathInfo=$manager->removeUrlSuffix($rawPathInfo,$this->urlSuffix);

    // URL suffix required, but not found in the requested URL
    if($manager->useStrictParsing && $pathInfo===$rawPathInfo)
    {
        $urlSuffix=$this->urlSuffix===null ? $manager->urlSuffix : $this->urlSuffix;
        if($urlSuffix!='' && $urlSuffix!=='/')
            return false;
    }

    if($this->hasHostInfo)
        $pathInfo=strtolower($request->getHostInfo()).rtrim('/'.$pathInfo,'/');

    $pathInfo.='/';

    if(preg_match($this->pattern.$case,$pathInfo,$matches))
    {
        foreach($this->defaultParams as $name=>$value)
        {
            if(!isset($_GET[$name]))
                $_REQUEST[$name]=$_GET[$name]=$value;
        }
        $tr=array();
        foreach($matches as $key=>$value)
        {
            if(isset($this->references[$key]))
                $tr[$this->references[$key]]=$value;
            else if(isset($this->params[$key]))
                $_REQUEST[$key]=$_GET[$key]=$value;
        }
        if($pathInfo!==$matches[0]) // there're additional GET params
            $manager->parsePathInfo(ltrim(substr($pathInfo,strlen($matches[0])),'/'));
        if($this->routePattern!==null)
            return strtr($this->route,$tr);
        else
            return $this->route;
    }
    else
        return false;
}