yii2用表單上傳文件經常用到的

1、單個文件上傳

首先建立一個模型models/UploadForm.php,內容如下

<?php
namespace app\models;

use yii\base\Model;
use yii\web\UploadedFile;

/**
 * UploadForm is the model behind the upload form.
 */
class UploadForm extends Model
{
    /**
     * @var UploadedFile file attribute
     */
    public $file;

    /**
     * @return array the validation rules.
     */
    public function rules()
    {
        return [
            [['file'], 'file'],
        ];
    }
}
?>

再在對應的視圖文件夾裏建立一個視圖（html）文件，內容如下:

<?php
use yii\widgets\ActiveForm;
?>

<?php $form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]) ?>

<?= $form->field($model, 'file')->fileInput() ?>

<button>Submit</button>

<?php ActiveForm::end() ?>

最後建立控制器文件，內容如下：

<?php
namespace app\controllers;

use Yii;
use yii\web\Controller;
use app\models\UploadForm;
use yii\web\UploadedFile;

class SiteController extends Controller
{
    public function actionUpload()
    {
        $model = new UploadForm();

        if (Yii::$app->request->isPost) {
            $model->file = UploadedFile::getInstance($model, 'file');

            if ($model->file && $model->validate()) {                
                $model->file->saveAs('uploads/' . $model->file->baseName . '.' . $model->file->extension);
            }
        }

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

注意這裏我們沒有用model->load(…)，而是用了UploadedFile::getInstance(…)。區別是後者不會執行model−>validate()，所以需要手動的去執行 model->validate()來檢驗數據的合法性。如果檢驗通過了，上傳的文件保存在uploads文件夾下，即web目錄下的uploads裏。

一些可選的配置選項
上傳文件不能爲空

public function rules()
{
    return [
        [['file'], 'file', 'skipOnEmpty' => false],
    ];
}

上傳類型，不僅可以根據擴展名檢驗，還可以根據文件的內容進行檢驗

public function rules()
{
    return [
        [['file'], 'file', 'extensions' => 'jpg, png', 'mimeTypes' => 'image/jpeg, image/png',],
    ];
}

2、多文件上傳

如果你想一次上傳多個文件，只需調節幾個參數就可以達到目的

模型層（model）：

class UploadForm extends Model
{
    /**
     * @var UploadedFile|Null file attribute
     */
    public $file;

    /**
     * @return array the validation rules.
     */
    public function rules()
    {
        return [
            [['file'], 'file', 'maxFiles' => 10], // <--- here!
        ];
    }
}

視圖層（view）:

<?php
use yii\widgets\ActiveForm;

$form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]);
?>

<?= $form->field($model, 'file[]')->fileInput(['multiple' => true]) ?>

    <button>Submit</button>

<?php ActiveForm::end(); ?>

與單文件上傳不同的是下面這句:

$form->field($model, 'file[]')->fileInput(['multiple' => true])

控制器層（Controller）：

<?php
namespace app\controllers;

use Yii;
use yii\web\Controller;
use app\models\UploadForm;
use yii\web\UploadedFile;

class SiteController extends Controller
{
    public function actionUpload()
    {
        $model = new UploadForm();

        if (Yii::$app->request->isPost) {
            $model->file = UploadedFile::getInstances($model, 'file');

            if ($model->file && $model->validate()) {
                foreach ($model->file as $file) {
                    $file->saveAs('uploads/' . $file->baseName . '.' . $file->extension);
                }
            }
        }

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