common/components 路径下新建Upload.php

<?php
namespace common\components;

use yii;
use yii\web\UploadedFile;
use yii\helpers\FileHelper;

class Upload
{
    /**
     * @param \yii\base\Model $model 实例化模型
     * @param string $inputName  <input name="$inputName">
     * @param array $config 上传文件配置
     * @return array
     */
    public function upload($model, $inputName, $config = [])
    {
        // 文件上传路径
        $folder = isset($config['uploadPath']) ? '/' . $config['uploadPath'] . '/' : '/';
        $path = Yii::getAlias('@uploads') . $folder;
        if (FileHelper::createDirectory($path) === true) {
            $files = UploadedFile::getInstance($model, $inputName);
            if ($files) {
                $fileSize = isset($config['fileSize']) ? $config['fileSize'] : 50 * 1024 * 1024; // 默认50M
                $allowType = isset($config['allowType']) ? $config['allowType'] : ['jpg', 'jpeg', 'gif', 'png', 'bmp'];

                // 扩展名
                $ext = $files->getExtension();
                if (empty($ext)) {
                    $ext_tmp = explode('/', $files->type);
                    $ext = isset($ext_tmp[1]) ? $ext_tmp[1] : '';
                }
                if (!in_array(strtolower($ext), $allowType)) {
                    return ['code' => -1, 'msg' => '上传的文件类型不允许', 'data' => []];
                }

                // 文件大小
                if ($files->size > $fileSize) {
                    return ['code' => -1, 'msg' => '上传的文件大小超过给定值', 'data' => []];
                }

                // 文件名
                $fileName = uniqid() . '.' . $ext;
                if ($files->saveAs($path . $fileName)) {
                    return ['code' => 0, 'msg' => '上传成功', 'data' => $folder . $fileName];
                } else {
                    return ['code' => -1, 'msg' => '文件保存失败', 'data' => []];
                }
            } else {
                return ['code' => -1, 'msg' => '未上传文件', 'data' => []];
            }
        } else {
            return ['code' => -1, 'msg' => '上传路径错误', 'data' => []];
        }
    }
}

调用第一种方法：
可在common\config/main.php 配置组件

'uploadFile' => [
    'class' => 'common\components\Upload',
],

调用

$logo = Yii::$app->uploadFile->uploadImage($model, '/logo/', 'logoFile');

第二种：直接实例化调用

use common\components\Upload;
$upload = new Upload();
$upload->uploadImage($model, '/logo/', 'logoFile');