PHP实现无刷新多图上传及远程图片处理

本文将介绍如何在 PHP 中实现无刷新的多图上传功能，同时支持远程图片的下载和处理。我们将通过一个示例来展示整个过程。

1. 上传页面（upload.php）

    选择图片: 
    
    

2. 处理上传的 PHP 脚本（upload_handler.php）

class ImageUploader {
    private $directory;
    private $allowedExtensiOns= ['jpg', 'jpeg', 'png', 'gif'];
    private $errors = [];
    private $uploadedFiles = [];

    public function __construct($directory) {
        $this->directory = $directory;
        if (!is_dir($directory)) {
            mkdir($directory, 0777, true);
        }
    }

    public function uploadFiles($files) {
        foreach ($files['file']['name'] as $key => $name) {
            $tmpName = $files['file']['tmp_name'][$key];
            $size = $files['file']['size'][$key];
            $error = $files['file']['error'][$key];
            $extension = strtolower(pathinfo($name, PATHINFO_EXTENSION));

            if (!in_array($extension, $this->allowedExtensions)) {
                $this->errors[] = "不允许的文件类型: $name";
                continue;
            }

            if ($error !== UPLOAD_ERR_OK) {
                $this->errors[] = "上传错误: $name";
                continue;
            }

            $newName = uniqid() . '.' . $extension;
            $destination = $this->directory . '/' . $newName;

            if (move_uploaded_file($tmpName, $destination)) {
                chmod($destination, 0777);
                $this->uploadedFiles[] = $newName;
            } else {
                $this->errors[] = "移动文件失败: $name";
            }
        }
    }

    public function grabRemoteImage($url) {
        $extension = pathinfo($url, PATHINFO_EXTENSION);
        if (!in_array($extension, $this->allowedExtensions)) {
            $this->errors[] = "不允许的文件类型: $url";
            return;
        }

        $newName = uniqid() . '.' . $extension;
        $destination = $this->directory . '/' . $newName;

        $imageData = file_get_contents($url);
        if (file_put_contents($destination, $imageData) !== false) {
            chmod($destination, 0777);
            $this->uploadedFiles[] = $newName;
        } else {
            $this->errors[] = "保存远程图片失败: $url";
        }
    }

    public function createThumbnail($source, $destination, $width, $height) {
        list($originalWidth, $originalHeight, $type) = getimagesize($source);
        switch ($type) {
            case IMAGETYPE_GIF:
                $image = imagecreatefromgif($source);
                break;
            case IMAGETYPE_JPEG:
                $image = imagecreatefromjpeg($source);
                break;
            case IMAGETYPE_PNG:
                $image = imagecreatefrompng($source);
                break;
            default:
                $this->errors[] = "不支持的图片类型: $source";
                return;
        }

        $thumbnail = imagecreatetruecolor($width, $height);
        imagecopyresampled($thumbnail, $image, 0, 0, 0, 0, $width, $height, $originalWidth, $originalHeight);
        imagejpeg($thumbnail, $destination);
        imagedestroy($thumbnail);
        imagedestroy($image);
    }

    public function getErrors() {
        return $this->errors;
    }

    public function getUploadedFiles() {
        return $this->uploadedFiles;
    }
}

$uploader = new ImageUploader('uploads');
if (isset($_FILES['file'])) {
    $uploader->uploadFiles($_FILES);
} elseif (isset($_POST['url'])) {
    $uploader->grabRemoteImage($_POST['url']);
}

foreach ($uploader->getUploadedFiles() as $file) {
    $uploader->createThumbnail('uploads/' . $file, 'thumbnails/' . $file, 150, 150);
}

$respOnse= [
    'error' => count($uploader->getErrors()) > 0,
    'message' => implode('
', $uploader->getErrors()),
    'files' => $uploader->getUploadedFiles()
];
echo json_encode($response);
?>

以上代码展示了如何实现无刷新多图上传和远程图片下载的功能。通过 `upload.php` 页面，用户可以选择多个图片进行上传，上传过程通过隐藏的 iframe 实现无刷新效果。`upload_handler.php` 脚本负责处理上传的文件，包括验证文件类型、移动文件到目标目录、创建缩略图等操作。