php上传文件

<?php
header("Content-Type:text/html;charset=utf-8");
//check params
/*
//地图上传 php www post接口，客户端使用
            WWWForm form = new WWWForm();
            form.AddField("json_data", str);
            form.AddField("file_name", "test_upload1");
            StartCoroutine(upload(form));
        }
        string url = "127.0.0.1:7013/upload.php";

返回字符串类型
ok表示成功 其余表示失败 具体可看源代码echo值
*/
if (isset($_POST['file_name']) && isset($_POST['json_data'])) 
{
    $json = $_POST['json_data'];
    $len = strlen($json);
    if ($len > 100 * 1024) // 100kb
    {// out of size limit
        echo 'out-of-size';
    } 
    else 
    {
        $upload_dir = "../../../www/s/map";
        $dir = iconv("UTF-8", "GBK", $upload_dir);
        if (!file_exists($dir)) 
        {
            mkdir($dir, 0777, true);
        } 
        else 
        {

        }
        $file = $upload_dir . "/" . $_POST['file_name'] . ".json";
        if (is_file($file)) 
        {
            echo 'exist';
        } 
        else 
        {
            file_put_contents($file, $json);
            echo 'ok';
        }
    }
}
else 
{
    echo 'error';
}