Makes loop-detection threshold configurable.

config/install/redirect.settings.yml

@@ -7,3 +7,4 @@ global_clean: true
 global_admin_paths: false
 global_home: true
 global_deslash: false
+loop_threshold: 5

config/schema/redirect.schema.yml

@@ -31,3 +31,6 @@ redirect.settings:
     global_deslash:
       type: boolean
       label: 'Remove trailing slashes from paths.'
+    loop_threshold:
+      type: integer
+      label: 'Number of redirects in a 15-second period that will determine a redirect loop.'

src/Form/RedirectSettingsForm.php

@@ -55,6 +55,14 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#options' => redirect_status_code_options(),
       '#default_value' => $config->get('default_status_code'),
     );
+    $form['redirect_loop_threshold'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Loop detection threshold'),
+      '#description' => $this->t('Number of repeated redirects from a single user in a 15-second time period that will cause a redirect loop to be detected.'),
+      '#options' => [0 => $this->t('Disable loop detection'), 5 => 5, 10 => 10, 15 => 15],
+      '#default_value' => $config->get('loop_threshold'),
+    ];
+
     $form['globals'] = array(
       '#type' => 'fieldset',
       '#title' => $this->t('Global redirects'),
@@ -102,7 +110,6 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
       }
     }
     $config->save();
-    redirect_page_cache_clear();
     drupal_set_message(t('Configuration was saved.'));
   }
 

src/RedirectChecker.php

@@ -86,13 +86,17 @@ public function canRedirect(Request $request) {
    *   TRUE if a redirect loop has been identified.
    */
   public function isLoop(Request $request) {
-    $hash = Crypt::hashBase64('redirection' . $request->getRequestUri());
-    if ($this->flood->isAllowed($hash, 5, 15)) {
-      $this->flood->register($hash, 60);
+    if (!$this->config->get('loop_threshold')) {
+      // Loop detection is disabled.
+      return FALSE;
+    }
+    if ($this->flood->isAllowed('redirection', $this->config->get('loop_threshold'), 15)) {
+      $this->flood->register('redirection', 60);
       return FALSE;
     }
     else {
       return TRUE;
     }
   }
+
 }

src/Tests/RedirectUITest.php

@@ -306,39 +306,34 @@ function testRedirectLoop() {
       $log = reset($log);
       $this->assertEqual($log->severity, RfcLogLevel::WARNING);
       $this->assertEqual(SafeMarkup::format($log->message, unserialize($log->variables)),
-        SafeMarkup::format('Redirect loop identified at %path for redirect %id', array('%path' => '/node', '%id' => $redirect1->id())));
-    }
-
-    // Test flood protection.
-    // Create 20 redirects.
-    $redirects = [];
-    for ($i = 0; $i < 20; $i++) {
-      $redirect = $this->storage->create();
-      $redirect->setSource('test-redirect' . $i);
-      $redirect->setRedirect('node');
-      $redirect->setStatusCode(301);
-      $redirect->save();
-      $redirects[$i] = $redirect;
+        SafeMarkup::format('Redirect loop identified at %path for redirect %id', array('%path' => '/admin', '%id' => $redirect2->id())));
     }
+  }
 
-    // Hit the first redirect 10 times, should result in a loop.
-    for ($i = 0; $i < 10; $i++) {
-      // Should detect a redirect after 4.
-      if ($i > 4) {
-        $this->drupalGet('test-redirect0');
+  /**
+   * Test loop detection threshold.
+   */
+  public function testLoopThreshold() {
+    $redirect = $this->storage->create();
+    $redirect->setSource('test-redirect');
+    $redirect->setRedirect('node');
+    $redirect->setStatusCode(301);
+    $redirect->save();
+
+    // Set loop threshold to 3.
+    \Drupal::configFactory()->getEditable('redirect.settings')->set('loop_threshold', 3)->save();
+    // Hit the first redirect 5 times, should result in a loop.
+    for ($i = 0; $i < 5; $i++) {
+      // Should detect a redirect loop after 3.
+      if ($i > 2) {
+        $this->drupalGet('test-redirect');
         $this->assertText('Service unavailable');
         $this->assertResponse(503);
       }
       else {
-        $this->assertRedirect('test-redirect0', 'node');
+        $this->assertRedirect('test-redirect', 'node');
       }
     }
-    unset($redirects[0]);
-
-    // Hitting each different redirect should work.
-    foreach ($redirects as $i => $redirect) {
-      $this->assertRedirect('test-redirect' . $i, 'node');
-    }
   }
 
   /**