使用post rest call - swift & php编码问题上传图像

func uploadImage(image: UIImage) {
    guard let url = URL(string: "http://example.com/upload.php") else {
        print("Invalid URL")
        return
    }
    
    let request = NSMutableURLRequest(url: url)
    request.httpMethod = "POST"
    
    let boundary = "Boundary-\(UUID().uuidString)"
    let contentType = "multipart/form-data; boundary=\(boundary)"
    request.setValue(contentType, forHTTPHeaderField: "Content-Type")
    
    let body = NSMutableData()
    
    if let imageData = image.jpegData(compressionQuality: 0.8) {
        body.append("--\(boundary)\r\n".data(using: .utf8)!)
        body.append("Content-Disposition: form-data; name=\"image\"; filename=\"image.jpg\"\r\n".data(using: .utf8)!)
        body.append("Content-Type: image/jpeg\r\n\r\n".data(using: .utf8)!)
        body.append(imageData)
        body.append("\r\n".data(using: .utf8)!)
    }
    
    body.append("--\(boundary)--\r\n".data(using: .utf8)!)
    
    request.httpBody = body as Data
    
    let task = URLSession.shared.dataTask(with: request as URLRequest) { (data, response, error) in
        if let error = error {
            print("Error: \(error)")
            return
        }
        
        if let data = data {
            // 处理上传成功后的响应数据
            let responseString = String(data: data, encoding: .utf8)
            print("Response: \(responseString)")
        }
    }
    
    task.resume()
}

<?php
$targetDir = "uploads/";
$targetFile = $targetDir . basename($_FILES["image"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($targetFile,PATHINFO_EXTENSION));

// 检查图像文件的有效性
if(isset($_POST["submit"])) {
    $check = getimagesize($_FILES["image"]["tmp_name"]);
    if($check !== false) {
        echo "File is an image - " . $check["mime"] . ".";
        $uploadOk = 1;
    } else {
        echo "File is not an image.";
        $uploadOk = 0;
    }
}

// 检查文件是否已存在
if (file_exists($targetFile)) {
    echo "Sorry, file already exists.";
    $uploadOk = 0;
}

// 检查文件大小
if ($_FILES["image"]["size"] > 500000) {
    echo "Sorry, your file is too large.";
    $uploadOk = 0;
}

// 允许特定的文件格式
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
&& $imageFileType != "gif" ) {
    echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
    $uploadOk = 0;
}

// 检查$uploadOk的值是否为0，表示文件上传是否成功
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
} else {
    if (move_uploaded_file($_FILES["image"]["tmp_name"], $targetFile)) {
        echo "The file ". basename( $_FILES["image"]["name"]). " has been uploaded.";
    } else {
        echo "Sorry, there was an error uploading your file.";
    }
}
?>