PHP标头到期检查

时间:2012-03-12 11:26:09

标签: php caching header http-headers

我创建了一个自定义应用程序,我喜欢将一些PHP变量传递给CSS。

我使用的方法是一个提供CSS标头的style.php文件,因此HTTP请求它将请求作为普通的CSS文件来处理。

这种方法的问题在于,每次请求时,我都必须在内存中加载一些大的PHP文件。

我想做的是检查文件的截止日期,如果文件尚未过期,则不要运行脚本,而是发送缓存文件。

那么,该问题是否有解决方案?

我的php文件我喜欢看起来像这样:

<?php
    // Enter here several headers to cache the file and other operations
    // Check here if the file must be re-executed or load a cached version instead
    // Enter here the inclution of my application scripts with include_once(....)
?>
body
{
    background-color: <?php echo $options->css['bg_color']; ?>
}

亲切的问候 Merianos Nikos

1 个答案:

答案 0 :(得分:1)

我必须做一些类似于你正在做的事情并解决了解析CSS文件服务器端的问题。这是一个link到一个简单的类就可以做到(这就是我现在使用的)。基本上它解析目录中的所有文件,并使用strtr()替换css文件中的值

class Css {
    //this is an associative array that's used when replacing
    private $settings;
    //This is the path (relative to this file) to the dir that holds the css files to parse
    private $cssDir = "css/";
    //private varray to store the files
    private $cssFiles = array();
    //This is the path (relative to this file) to the dir where the parsed css files wil be written
    private $outCssDir = "../css/";

    /**
     * the class thake only one parameters, an associative array of keys to replace with their respective values
     */
    function __construct($settings) {
        $this -> settings = $settings;
        $this -> readFiles();
        $this -> replaceValuesInCssStrings();

    }

    private function readFiles() {
        $dir = dirname(__FILE__) . DIRECTORY_SEPARATOR . $this -> cssDir;
        if (file_exists($dir)) {
            if ($handle = opendir($dir)) {
                /* This is the correct way to loop over the directory. */
                while (false !== ($entry = readdir($handle))) {
                    //filter out .. and .
                    if ($entry !== "." && $entry !== "..") {
                        $cssFiles[$entry] = file_get_contents($dir . $entry);
                    }
                }

                closedir($handle);
            }
        }
        $this -> cssFiles = $cssFiles;

    }

    private function replaceValuesInCssStrings() {
        foreach ($this->cssFiles as $fileName => $fileContent) {
            $this->cssFiles[$fileName] = strtr($fileContent, $this-> settings);

        }
    }
    /**
     * renders the parsed css files in a <style> tag
     */
    public function render() {
        $css = "<style>\n";
        foreach ($this -> cssFiles as $fileContent) {
            $css .= $fileContent;
        }
        $css .= "</style>";
        echo($css);
    }

    /**
     * writes the parsed css files to the $outCssDir (keeping their names intact)
     */
    public function renderToFile() {
        $dir = dirname(__FILE__) . DIRECTORY_SEPARATOR . $this -> outCssDir;
        if (file_exists($dir)) {
            foreach($this->cssFiles as $fileName => $fileContent){
                file_put_contents($dir . $fileName, $fileContent);

            }   
        }
    }
    /**
     *  this is just in case you want to call echo ($css)
     */
    public function __toString() {
        $this -> render();
    }

}