Yii2图片上传验证，无model。

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1 
$file = UploadedFile::getInstanceByName('editormd-image-file');
if($file->hasError){
		$res['message'] = $file->error;
		return $res;
}
if(!$file->size){
		$res['message'] = '文件内容是空的';
		return $res;
}
$allowTypes = ['image/jpeg', 'image/png', 'image/gif', 'image/bmp'];
if(!in_array($file->type, $allowTypes)){
		$res['message'] = '图片格式不正确';
		return $res;
}
// 验证文件格式
if (!in_array($file->extension, ['jpg', 'gif', 'png', 'jpeg', 'bmp'])){
		$res['message'] = '图片格式不正确';
		return $res;
}
// 验证文件大小
if ($file->size >= 1024*1024*3){
		$res['message'] = '图片大小超限[<=3mb]';
		return $res;
}
if ($file) {
		$randomNumber = microtime() . mt_rand(111111, 999999);
		$filename = md5($randomNumber) . '.' . $file->extension;
		$randomFolder = date('Ymd');
		$savePath = '/uploads_nj/' . $randomFolder . '/' . $filename;
		$trueSavePath = Yii::getAlias('@app/web').$savePath;
		if (!yiihelpersFileHelper::createDirectory(dirname($trueSavePath))){
				$res['message'] = '目录权限错误';
				return $res;
		}
		if($file->saveAs($trueSavePath)){
				$res['success'] = 1;
				$res['url'] = $this->getHost().$savePath;
		}else{
				$res['message'] = $file->error;
				return $res;
		}
}