提取并缓存JSON文件

Question

提取JSON文件并将其缓存在服务器上的最佳方法是什么？ 我想从远程来源获取JSON文件并将其缓存（例如24小时），以便其花费更少的互联网容量:)

class Json {
    public $url;
    public $hash;

    public function LoadJson($url) {
        // Exist function
        if (file_exists($hash)) {
            // Load md5 file
            return $hash;
        } else {
            $json_file = file_get_contents($url);
            $jfo = json_decode($json_file);
            // Save json file on server
            // Convert url to md5
        }
    }
}

$MyJson = new Json;
$MyJson->LoadJson('http://google.com/file.json');

Answer 1

您将需要的关键成分是：

• 您想在哪里存储缓存的文件
• 检查缓存是否存在并且是否在24小时内
• 如果不存在，请下载内容并将其保存到缓存文件中

这是我根据您的情况创建的一个类：

class Json {
    public $url;
    public $hash;
    //set cache directory here
    private $fileLocation = 'd:/temp/';

    public function LoadJson($url) {
        $hash = md5($url);
        //set your cached offline file as variable for ease of use
        $cachedFile = $this->fileLocation . $hash;
        //check if file exists
        if (file_exists($cachedFile)) {
            echo "cache exists\n";
            //check if file age is within 24 hours
            if(time() - filemtime($filename) > (24 * 3600)) {
                echo "cache is within 24 hours\n";
                return file_get_contents($cachedFile);
            }
        }

        echo "cache doesn't exists or is older than 24 hours\n";
        //cache doesn't exist of is older than 24 hours
        //download it
        $jsonFile = file_get_contents($url);
        // Save content into cache
        file_put_contents($cachedFile, $jsonFile);
        //return downloaded content as result
        return $jsonFile;
    }
}

这是上述课程的代码段测试：

Arief Bayu Purwanto@DESKTOP-H097T2S MINGW32 ~
$ php /d/temp/json-cache.php
cache doesn't exists or is older than 24 hours

Arief Bayu Purwanto@DESKTOP-H097T2S MINGW32 ~
$ php /d/temp/json-cache.php
cache exists
cache is within 24 hours

Arief Bayu Purwanto@DESKTOP-H097T2S MINGW32 ~