php curl form-data上傳file方法

<?php


class UploadPart
{   
    protected static $url;
    protected static $delimiter;
    protected static $instance;
 
    public function __construct() {
        static::$url = 'http://xx/yasuotupian.php';
        static::$delimiter = uniqid();
    }
 
    public function putPart($param) {
        $post_data 
 
= static::buildData($param);
        $curl = curl_init(static::$url);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_POST, true);
        curl_setopt($curl, CURLOPT_POSTFIELDS, $post_data);
        curl_setopt($curl, CURLOPT_HTTPHEADER, [
            "Content-Type: multipart/form-data; boundary=
 
" . static::$delimiter,
            "Content-Length: " . strlen($post_data)
        ]);
        $response = curl_exec($curl);
        curl_close($curl);
 
        return $response;
    }
 
    private static function buildData($param){
        $data = '';
        $eol = "\r\n";
        $upload = $param['
 
upload'];
        unset($param['upload']);
 
        foreach ($param as $name => $content) {
            $data .= "--" . static::$delimiter . "\r\n"
                . 'Content-Disposition: form-data; name="' . $name . "\"\r\n\r\n"
                . $content . "\r\n";
        }
        // 拼接檔案流
        $data .= "--" . static::$delimiter . $eol
            . 'Content-Disposition: form-data; name="file"; filename="' . $param['filename'] . '"' . "\r\n"
            . 'Content-Type:application/octet-stream'."\r\n\r\n";
 
        $data .= $upload . "\r\n";
        $data .= "--" . static::$delimiter . "--\r\n";
        return $data;
    }
 
    public static function getInstance() {
        if(!static::$instance){
            static::$instance = new static();
        }
       return static::$instance;
    }
 
}

$fields = array(
    'filename' => 'spineboy.png',
    'upload'=>file_get_contents('ss/spineboy.png')
);
$part = UploadPart::getInstance()->putPart($fields);

print_r($part);
exit();

這個程式碼是拼接的