如何解决Yii2文件上传和图片缩略图管理的痛点，使用mohorev/yii2-upload-behavior轻松搞定

<code class="bash">composer require --prefer-dist mohorev/yii2-upload-behavior "*"</code>

<code class="json">"mohorev/yii2-upload-behavior": "*"</code>

<pre class="brush:php;toolbar:false;"><?php

namespace app\models;

use Yii;
use yii\db\ActiveRecord;
use mohorev\file\UploadBehavior; // 引入行为类

class Document extends ActiveRecord
{
    public $file; // 定义一个属性来接收上传的文件

    public function rules()
    {
        return [
            // 验证文件，确保是doc, docx, pdf格式，并在insert和update场景下启用
            ['file', 'file', 'extensions' => 'doc, docx, pdf', 'on' => ['insert', 'update']],
        ];
    }

    public function behaviors()
    {
        return [
            [
                'class' => UploadBehavior::class, // 使用文件上传行为
                'attribute' => 'file', // 关联模型中的文件属性
                'scenarios' => ['insert', 'update'], // 行为生效的场景
                // 文件保存路径，支持别名和模型属性占位符
                'path' => '@webroot/upload/docs/{category.id}', 
                // 文件访问URL，同样支持别名和模型属性占位符
                'url' => '@web/upload/docs/{category.id}',
            ],
        ];
    }

    // 假设你有一个Category关联
    public function getCategory()
    {
        return $this->hasOne(Category::class, [ 'id' => 'id_category' ]);
    }
}

<pre class="brush:php;toolbar:false;"><?php

namespace app\controllers;

use Yii;
use yii\web\Controller;
use app\models\Document;

class DocumentController extends Controller
{
    public function actionCreate()
    {
        $model = new Document();
        $model->setScenario('insert'); // 关键：设置上传行为的场景

        if ($model->load(Yii::$app->request->post()) && $model->save()) {
            Yii::$app->session->setFlash('success', '文档上传成功！');
            return $this->redirect(['view', 'id' => $model->id]);
        }

        return $this->render('create', ['model' => $model]);
    }
}

<pre class="brush:php;toolbar:false;"><?php
use yii\widgets\ActiveForm;
use yii\helpers\Html;
?>

<?php $form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]); ?>
    <?= $form->field($model, 'file')->fileInput() ?>
    <div class="form-group">
        <?= Html::submitButton('提交', ['class' => 'btn btn-primary']) ?>
    </div>
<?php ActiveForm::end(); ?>

<code class="bash">composer require yiisoft/yii2-imagine</code>

<pre class="brush:php;toolbar:false;"><?php

namespace app\models;

use Yii;
use yii\db\ActiveRecord;
use mohorev\file\UploadImageBehavior; // 引入图片上传行为

class User extends ActiveRecord
{
    public $image; // 定义一个属性来接收上传的图片

    public function rules()
    {
        return [
            // 验证图片，确保是jpg, jpeg, gif, png格式
            ['image', 'image', 'extensions' => 'jpg, jpeg, gif, png', 'on' => ['insert', 'update']],
        ];
    }

    public function behaviors()
    {
        return [
            [
                'class' => UploadImageBehavior::class,
                'attribute' => 'image',
                'scenarios' => ['insert', 'update'],
                'placeholder' => '@app/modules/user/assets/images/userpic.jpg', // 默认占位图
                'path' => '@webroot/upload/user/{id}', // 图片保存路径
                'url' => '@web/upload/user/{id}',     // 图片访问URL
                'thumbs' => [ // 缩略图配置
                    'thumb' => ['width' => 400, 'quality' => 90], // 生成名为'thumb'的缩略图，宽度400，质量90
                    'preview' => ['width' => 200, 'height' => 200, 'bg_color' => '000'], // 生成名为'preview'的缩略图，200x200，黑色背景
                    // 还可以添加更多缩略图配置
                ],
                'deleteOriginalFile' => false, // 是否在生成缩略图后删除原图，默认为false
            ],
        ];
    }
}

<pre class="brush:php;toolbar:false;"><?php
use yii\widgets\ActiveForm;
use yii\helpers\Html;
?>

<?php $form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]); ?>
    <div class="form-group">
        <div class="row">
            <div class="col-lg-6">
                <h4>原图</h4>
                <?= Html::img($model->getUploadUrl('image'), ['class' => 'img-thumbnail']) ?>
            </div>
            <div class="col-lg-4">
                <h4>缩略图 (400px宽)</h4>
                <?= Html::img($model->getThumbUploadUrl('image'), ['class' => 'img-thumbnail']) ?>
            </div>
            <div class="col-lg-2">
                <h4>预览图 (200x200)</h4>
                <?= Html::img($model->getThumbUploadUrl('image', 'preview'), ['class' => 'img-thumbnail']) ?>
            </div>
        </div>
    </div>
    <?= $form->field($model, 'image')->fileInput(['accept' => 'image/*']) ?>
    <div class="form-group">
        <?= Html::submitButton('提交', ['class' => 'btn btn-primary']) ?>
    </div>
<?php ActiveForm::end(); ?>

<pre class="brush:php;toolbar:false;">// 这是一个不推荐的例子！
class Track extends ActiveRecord
{
    public function getArtist()
    {
        return $this->hasOne(Artist::class, [ 'id' => 'id_artist' ]);
    }

    public function behaviors()
    {
        return [
            [
                'class' => UploadBehavior::class,
                'attribute' => 'image',
                'scenarios' => ['default'],
                'path' => '@webroot/uploads/{artist.slug}', // 这里的slug是可变的
                'url' => '@web/uploads/{artist.slug}',
            ],
        ];
    }
}