YII2 - Save user ID to work with it on other pages

Question

I'm building a questionnaire site.
On this site the user enters his email to receive the result of his questionnaire. So this site has no authentication.

How do I store the user's email to the end of the questionnaire?

It is my User model:

<?php

namespace common\models;

use Yii;
use \yii\db\ActiveRecord;
// use yii\web\IdentityInterface;

/**
 * This is the model class for table "user".
 *
 * @property int $id
 * @property string $email
 * @property string $name
 * @property string $family
 * @property string $major
 * @property string $univercity
 * @property int $education
 * @property int $gender
 * @property int $age
 * @property int $income
 * @property int $get_result
 * @property int $created_at
 */
class User extends ActiveRecord
{
    /**
     * {@inheritdoc}
     */
    public static function tableName()
    {
        return 'user';
    }

    /**
     * {@inheritdoc}
     */
    public function behaviors()
    {
        return [
            // TimestampBehavior::className(),
        ];
    }


    /**
     * {@inheritdoc}
     */
    public function rules()
    {
        return [
            [['email', 'created_at'], 'required'],
            [['education', 'gender', 'age', 'income', 'get_result', 'created_at'], 'integer'],
            [['email', 'name', 'family', 'major', 'univercity'], 'string', 'max' => 255],
            [['email'], 'unique'],
        ];
    }

    /**
     * {@inheritdoc}
     */
    public function attributeLabels()
    {
        return [
            'id' => 'ID',
            'email' => 'Email',
            'name' => 'Name',
            'family' => 'Family',
            'major' => 'Major',
            'univercity' => 'Univercity',
            'education' => 'Education',
            'gender' => 'Gender',
            'age' => 'Age',
            'income' => 'Income',
            'get_result' => 'Get Result',
            'created_at' => 'Created At',
        ];
    }
}

Answer 1

There are many ways of achieving that, it mostly depends on your logic under the hood.

One of the easiest is to use session.

First store the email in session:

\Yii::$app->session->set('questionnaire-email', $usersEmail);

Then, when you want to use it:

$email = \Yii::$app->session->get('questionnaire-email');