Breadcrumbs sub-module (#132)

* initial commit

* break looped chains

* add depthLimit and includeSelf configuration

* clean up configuration

* breadcrumb tests

* enable tests in travis

* fix travis tests

.travis.yml

@@ -28,6 +28,7 @@ install:
 script:
   - $SCRIPT_DIR/travis_scripts.sh
   - $SCRIPT_DIR/run-tests.sh "islandora"
+  - $SCRIPT_DIR/run-tests.sh "islandora_breadcrumbs"
 
 notifications:
   irc:

modules/islandora_breadcrumbs/config/install/islandora.breadcrumbs.yml

@@ -0,0 +1,3 @@
+maxDepth: -1
+includeSelf: FALSE
+referenceField: field_member_of

modules/islandora_breadcrumbs/config/schema/islandora_breadcrumbs.schema.yml

@@ -0,0 +1,12 @@
+islandora.breadcrumbs:
+  type: config_object
+  mapping:
+    maxDepth:
+      type: integer
+      label: 'Max Depth'
+    includeSelf:
+      type: boolean
+      label: 'Include Self'
+    referenceField:
+      type: string
+      label: 'Reference Field'

modules/islandora_breadcrumbs/islandora_breadcrumbs.info.yml

@@ -0,0 +1,7 @@
+name: 'Islandora Breadcrumbs'
+type: module
+description: 'Builds breadcrumbs based on field_member_of relationships.'
+core: 8.x
+package: Islandora
+dependencies:
+  - islandora

modules/islandora_breadcrumbs/islandora_breadcrumbs.services.yml

@@ -0,0 +1,6 @@
+services:
+  islandora_breadcrumbs.breadcrumb:
+    class: Drupal\islandora_breadcrumbs\IslandoraBreadcrumbBuilder
+    arguments: ['@config.factory']
+    tags:
+      - { name: breadcrumb_builder, priority: 100 }

modules/islandora_breadcrumbs/src/IslandoraBreadcrumbBuilder.php

@@ -0,0 +1,96 @@
+<?php
+
+namespace Drupal\islandora_breadcrumbs;
+
+use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Breadcrumb\Breadcrumb;
+use Drupal\Core\Breadcrumb\BreadcrumbBuilderInterface;
+use Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Provides breadcrumbs for nodes using a configured entity reference field.
+ */
+class IslandoraBreadcrumbBuilder implements BreadcrumbBuilderInterface {
+
+  /**
+   * The configuration.
+   *
+   * @var \Drupal\Core\Config\ImmutableConfig
+   */
+  protected $config;
+
+  /**
+   * Constructs a breadcrumb builder.
+   *
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   The configuration factory.
+   */
+  public function __construct(ConfigFactoryInterface $config_factory) {
+    $this->config = $config_factory->get('islandora.breadcrumbs');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function applies(RouteMatchInterface $attributes) {
+    $parameters = $attributes->getParameters()->all();
+    if (!empty($parameters['node'])) {
+      return ($parameters['node']->hasField($this->config->get('referenceField')) &&
+              !$parameters['node']->get($this->config->get('referenceField'))->isEmpty());
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function build(RouteMatchInterface $route_match) {
+
+    $node = $route_match->getParameter('node');
+    $breadcrumb = new Breadcrumb();
+
+    $chain = [];
+    $this->walkMembership($node, $chain);
+
+    if (!$this->config->get('includeSelf')) {
+      array_pop($chain);
+    }
+    $breadcrumb->addCacheableDependency($node);
+
+    // Add membership chain to the breadcrumb.
+    foreach ($chain as $chainlink) {
+      $breadcrumb->addCacheableDependency($chainlink);
+      $breadcrumb->addLink($chainlink->toLink());
+    }
+    $breadcrumb->addCacheContexts(['route']);
+    return $breadcrumb;
+  }
+
+  /**
+   * Follows chain of field_member_of links.
+   *
+   * We pass crumbs by reference to enable checking for looped chains.
+   */
+  protected function walkMembership(EntityInterface $entity, &$crumbs) {
+    // Avoid infinate loops, return if we've seen this before.
+    foreach ($crumbs as $crumb) {
+      if ($crumb->uuid == $entity->uuid) {
+        return;
+      }
+    }
+
+    // Add this item onto the pile.
+    array_unshift($crumbs, $entity);
+
+    if ($this->config->get('maxDepth') > 0 && count($crumbs) >= $this->config->get('maxDepth')) {
+      return;
+    }
+
+    // Find the next in the chain, if there are any.
+    if ($entity->hasField($this->config->get('referenceField')) &&
+      !$entity->get($this->config->get('referenceField'))->isEmpty()) {
+      $this->walkMembership($entity->get($this->config->get('referenceField'))->entity, $crumbs);
+    }
+  }
+
+}

modules/islandora_breadcrumbs/tests/src/Functional/BreadcrumbsTest.php

@@ -0,0 +1,89 @@
+<?php
+
+namespace Drupal\Tests\islandora_breadcrumbs\Functional;
+
+use Drupal\Tests\islandora\Functional\IslandoraFunctionalTestBase;
+use Drupal\Tests\system\Functional\Menu\AssertBreadcrumbTrait;
+
+/**
+ * Tests the Islandora Breadcrumbs Builder.
+ *
+ * @group islandora_breadcrumbs
+ */
+class BreadcrumbsTest extends IslandoraFunctionalTestBase {
+
+  use AssertBreadcrumbTrait;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = [
+    'islandora_breadcrumbs',
+  ];
+
+
+  protected $nodeA;
+
+  protected $nodeB;
+
+  protected $nodeC;
+
+  protected $nodeD;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+
+    // Create some nodes.
+    $this->nodeA = $this->container->get('entity_type.manager')->getStorage('node')->create([
+      'type' => $this->testType->id(),
+      'title' => 'Node A',
+    ]);
+    $this->nodeA->save();
+
+    $this->nodeB = $this->container->get('entity_type.manager')->getStorage('node')->create([
+      'type' => $this->testType->id(),
+      'title' => 'Node B',
+    ]);
+    $this->nodeB->set('field_member_of', [$this->nodeA->id()]);
+    $this->nodeB->save();
+
+    $this->nodeC = $this->container->get('entity_type.manager')->getStorage('node')->create([
+      'type' => $this->testType->id(),
+      'title' => 'Node C',
+    ]);
+    $this->nodeC->set('field_member_of', [$this->nodeB->id()]);
+    $this->nodeC->save();
+
+    $this->nodeD = $this->container->get('entity_type.manager')->getStorage('node')->create([
+      'type' => $this->testType->id(),
+      'title' => 'Node D',
+    ]);
+    $this->nodeD->set('field_member_of', [$this->nodeC->id()]);
+    $this->nodeD->save();
+  }
+
+  /**
+   * @covers \Drupal\islandora_breadcrumbs\IslandoraBreadcrumbBuilder::applies
+   */
+  public function testDefaults() {
+    $breadcrumbs = [
+      $this->nodeC->toUrl()->toString() => $this->nodeC->label(),
+      $this->nodeB->toUrl()->toString() => $this->nodeB->label(),
+      $this->nodeA->toUrl()->toString() => $this->nodeA->label(),
+    ];
+    $this->assertBreadcrumb($this->nodeD->toUrl()->toString(), $breadcrumbs);
+
+    // Create a reference loop.
+    $this->nodeA->set('field_member_of', [$this->nodeD->id()]);
+    $this->nodeA->save();
+
+    // We should still escape it and have the same trail as before.
+    $this->assertBreadcrumb($this->nodeD->toUrl()->toString(), $breadcrumbs);
+  }
+
+}