StorageTest.php

<?php

namespace Drupal\Tests\system\Functional\Form;

use Drupal\Core\Database\Database;
use Drupal\Core\EventSubscriber\MainContentViewSubscriber;
use Drupal\Tests\BrowserTestBase;

/**
 * Tests a multistep form using form storage.
 *
 * The tested form puts data into the storage during the initial form
 * construction. These tests verify that there are no duplicate form
 * constructions, with and without manual form caching activated. Furthermore
 * when a validation error occurs, it makes sure that changed form element
 * values are not lost due to a wrong form rebuild.
 *
 * @group Form
 */
class StorageTest extends BrowserTestBase {
    
    /**
     * Modules to enable.
     *
     * @var array
     */
    protected static $modules = [
        'form_test',
        'dblog',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() : void {
        parent::setUp();
        $this->drupalLogin($this->drupalCreateUser());
    }
    
    /**
     * Tests using the form in a usual way.
     */
    public function testForm() {
        $this->drupalGet('form_test/form-storage');
        $assert_session = $this->assertSession();
        $assert_session->pageTextContains('Form constructions: 1');
        $edit = [
            'title' => 'new',
            'value' => 'value_is_set',
        ];
        // Use form rebuilding triggered by a submit button.
        $this->submitForm($edit, 'Continue submit');
        $assert_session->pageTextContains('Form constructions: 2');
        $assert_session->pageTextContains('Form constructions: 3');
        // Reset the form to the values of the storage, using a form rebuild
        // triggered by button of type button.
        $this->submitForm([
            'title' => 'changed',
        ], 'Reset');
        $assert_session->fieldValueEquals('title', 'new');
        // After rebuilding, the form has been cached.
        $assert_session->pageTextContains('Form constructions: 4');
        $this->submitForm($edit, 'Save');
        $assert_session->pageTextContains('Form constructions: 4');
        // Verify that the form storage has stored the values.
        $assert_session->pageTextContains('Title: new');
    }
    
    /**
     * Tests using the form after calling $form_state->setCached().
     */
    public function testFormCached() {
        $this->drupalGet('form_test/form-storage', [
            'query' => [
                'cache' => 1,
            ],
        ]);
        $this->assertSession()
            ->pageTextContains('Form constructions: 1');
        $edit = [
            'title' => 'new',
            'value' => 'value_is_set',
        ];
        // Use form rebuilding triggered by a submit button.
        $this->submitForm($edit, 'Continue submit');
        // The first one is for the building of the form.
        $this->assertSession()
            ->pageTextContains('Form constructions: 2');
        // The second one is for the rebuilding of the form.
        $this->assertSession()
            ->pageTextContains('Form constructions: 3');
        // Reset the form to the values of the storage, using a form rebuild
        // triggered by button of type button.
        $this->submitForm([
            'title' => 'changed',
        ], 'Reset');
        $this->assertSession()
            ->fieldValueEquals('title', 'new');
        $this->assertSession()
            ->pageTextContains('Form constructions: 4');
        $this->submitForm($edit, 'Save');
        $this->assertSession()
            ->pageTextContains('Form constructions: 4');
        // Verify that the form storage has stored the values.
        $this->assertSession()
            ->pageTextContains('Title: new');
    }
    
    /**
     * Tests validation when form storage is used.
     */
    public function testValidation() {
        $this->drupalGet('form_test/form-storage');
        $this->submitForm([
            'title' => '',
            'value' => 'value_is_set',
        ], 'Continue submit');
        // Ensure that the input values have been kept.
        $this->assertSession()
            ->responseMatches('/value_is_set/');
    }
    
    /**
     * Tests updating cached form storage during form validation.
     *
     * If form caching is enabled and a form stores data in the form storage, then
     * the form storage also has to be updated in case of a validation error in
     * the form. This test re-uses the existing form for multi-step tests, but
     * triggers a special #element_validate handler to update the form storage
     * during form validation, while another, required element in the form
     * triggers a form validation error.
     */
    public function testCachedFormStorageValidation() {
        // Request the form with 'cache' query parameter to enable form caching.
        $this->drupalGet('form_test/form-storage', [
            'query' => [
                'cache' => 1,
            ],
        ]);
        // Skip step 1 of the multi-step form, since the first step copies over
        // 'title' into form storage, but we want to verify that changes in the form
        // storage are updated in the cache during form validation.
        $edit = [
            'title' => 'foo',
        ];
        $this->submitForm($edit, 'Continue submit');
        // In step 2, trigger a validation error for the required 'title' field, and
        // post the special 'change_title' value for the 'value' field, which
        // conditionally invokes the #element_validate handler to update the form
        // storage.
        $edit = [
            'title' => '',
            'value' => 'change_title',
        ];
        $this->submitForm($edit, 'Save');
        // At this point, the form storage should contain updated values, but we do
        // not see them, because the form has not been rebuilt yet due to the
        // validation error. Post again and verify that the rebuilt form contains
        // the values of the updated form storage.
        $this->submitForm([
            'title' => 'foo',
            'value' => 'bar',
        ], 'Save');
        $this->assertSession()
            ->pageTextContains("The thing has been changed.");
    }
    
    /**
     * Tests form build ID regeneration when loading a cached immutable form.
     */
    public function testImmutableForm() {
        // Request the form with 'cache' query parameter to enable form caching.
        $this->drupalGet('form_test/form-storage', [
            'query' => [
                'cache' => 1,
                'immutable' => 1,
            ],
        ]);
        // Ensure the hidden 'form_build_id' field is unique.
        $this->assertSession()
            ->elementsCount('xpath', '//input[@name="form_build_id"]', 1);
        $buildId = $this->assertSession()
            ->hiddenFieldExists('form_build_id')
            ->getValue();
        // Trigger validation error by submitting an empty title.
        $edit = [
            'title' => '',
        ];
        $this->submitForm($edit, 'Continue submit');
        // Verify that the build-id did change.
        $this->assertSession()
            ->hiddenFieldValueNotEquals('form_build_id', $buildId);
        // Ensure the hidden 'form_build_id' field is unique.
        $this->assertSession()
            ->elementsCount('xpath', '//input[@name="form_build_id"]', 1);
        // Retrieve the new build-id.
        $buildId = (string) $this->assertSession()
            ->hiddenFieldExists('form_build_id')
            ->getValue();
        // Trigger validation error by again submitting an empty title.
        $edit = [
            'title' => '',
        ];
        $this->submitForm($edit, 'Continue submit');
        // Verify that the build-id does not change the second time.
        $this->assertSession()
            ->hiddenFieldValueEquals('form_build_id', $buildId);
    }
    
    /**
     * Verify that existing contrib code cannot overwrite immutable form state.
     */
    public function testImmutableFormLegacyProtection() {
        $this->drupalGet('form_test/form-storage', [
            'query' => [
                'cache' => 1,
                'immutable' => 1,
            ],
        ]);
        // Ensure the hidden 'form_build_id' field is unique.
        $this->assertSession()
            ->elementsCount('xpath', '//input[@name="form_build_id"]', 1);
        $build_id = $this->assertSession()
            ->hiddenFieldExists('form_build_id')
            ->getValue();
        // Try to poison the form cache.
        $response = $this->drupalGet('form-test/form-storage-legacy/' . $build_id, [
            'query' => [
                MainContentViewSubscriber::WRAPPER_FORMAT => 'drupal_ajax',
            ],
        ], [
            'X-Requested-With: XMLHttpRequest',
        ]);
        $original = json_decode($response, TRUE);
        $this->assertEquals($original['form']['#build_id_old'], $build_id, 'Original build_id was recorded');
        $this->assertNotEquals($original['form']['#build_id'], $build_id, 'New build_id was generated');
        // Assert that a watchdog message was logged by
        // \Drupal::formBuilder()->setCache().
        $status = (bool) Database::getConnection()->select('watchdog')
            ->condition('message', 'Form build-id mismatch detected while attempting to store a form in the cache.')
            ->range(0, 1)
            ->countQuery()
            ->execute()
            ->fetchField();
        $this->assertTrue($status, 'A watchdog message was logged by \\Drupal::formBuilder()->setCache');
        // Ensure that the form state was not poisoned by the preceding call.
        $response = $this->drupalGet('form-test/form-storage-legacy/' . $build_id, [
            'query' => [
                MainContentViewSubscriber::WRAPPER_FORMAT => 'drupal_ajax',
            ],
        ], [
            'X-Requested-With: XMLHttpRequest',
        ]);
        $original = json_decode($response, TRUE);
        $this->assertEquals($original['form']['#build_id_old'], $build_id, 'Original build_id was recorded');
        $this->assertNotEquals($original['form']['#build_id'], $build_id, 'New build_id was generated');
        $this->assertArrayNotHasKey('#poisoned', $original['form'], 'Original form structure was preserved');
        $this->assertArrayNotHasKey('poisoned', $original['form_state'], 'Original form state was preserved');
    }

}