Data discovery service (#3765)

modules/metastore/metastore.services.yml

@@ -104,3 +104,8 @@ services:
       - '@dkan.metastore.metastore_item_factory'
       - '@cache_tags.invalidator'
       - '@module_handler'
+
+  dkan.metastore.data_dictionary_discovery:
+    class: \Drupal\metastore\DataDictionary\DataDictionaryDiscovery
+    arguments:
+      - '@config.factory'

modules/metastore/src/DataDictionary/DataDictionaryDiscovery.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace Drupal\metastore\DataDictionary;
+
+use Drupal\Core\Config\ConfigFactoryInterface;
+
+/**
+ * Data dictionary service.
+ *
+ * Find the correct data dictionary for a dataset or distribution.
+ */
+class DataDictionaryDiscovery implements DataDictionaryDiscoveryInterface {
+
+  /**
+   * Constructor.
+   */
+  public function __construct(ConfigFactoryInterface $configFactory) {
+    $this->config = $configFactory->get('metastore.settings');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function dictionaryIdFromResource(string $resourceId, ?int $resourceIdVersion = NULL): ?string {
+    $mode = $this->getDataDictionaryMode();
+    // For now, we only support sitewide!
+    switch ($mode) {
+      case self::MODE_NONE:
+        return NULL;
+
+      case self::MODE_SITEWIDE:
+        return $this->getSitewideDictionaryId();
+
+      default:
+        throw new \OutOfRangeException("Unsupported data dictionary mode " . (string) $mode);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getSitewideDictionaryId(): string {
+    if ($identifier = $this->config->get('data_dictionary_sitewide')) {
+      return $identifier;
+    }
+    throw new \OutOfBoundsException("Attempted to retrieve a sitewide data dictionary, but none was set.");
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDataDictionaryMode(): int {
+    return $this->config->get('data_dictionary_mode') ?? self::MODE_NONE;
+  }
+
+}

modules/metastore/src/DataDictionary/DataDictionaryDiscoveryInterface.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace Drupal\metastore\DataDictionary;
+
+/**
+ * Provides interface for data dictionary discovery service.
+ */
+interface DataDictionaryDiscoveryInterface {
+
+  const MODE_NONE = 0;
+  const MODE_SITEWIDE = 1;
+  const MODE_COLLECTION = 2;
+  const MODE_GENERATE = 3;
+
+  /**
+   * Return the item ID for the appropriate data dictionary for a resource.
+   *
+   * @param string $resourceId
+   *   DKAN datastore resource identifier.
+   * @param int|null $resourceIdVersion
+   *   DKAN datastore resource version ID.
+   *
+   * @return string|null
+   *   The data dictionary identifier or NULL if none exists.
+   */
+  public function dictionaryIdFromResource(string $resourceId, ?int $resourceIdVersion = NULL): ?string;
+
+  /**
+   * Get the current data dictionary "mode" from DKAN config.
+   *
+   * Return values should represent modes like "single sitewide dictionary" or
+   * "distribution-specific dictionaries." The setting will have implications
+   * for behaviors in both the metastore and datastore sites of data dictionary
+   * functionality.
+   *
+   * @return int
+   *   Data dictionary mode. Returns one of the MODE_* constants.
+   */
+  public function getDataDictionaryMode(): int;
+
+  /**
+   * If a single sitewide data dictionary has been defined, return its ID.
+   *
+   * @return string
+   *   Data dictionary identifier.
+   */
+  public function getSitewideDictionaryId(): string;
+
+}

modules/metastore/tests/src/Unit/DataDictionary/DataDictionaryDiscoveryTest.php

@@ -0,0 +1,76 @@
+<?php
+
+namespace Drupal\Tests\metastore\Unit\DataDictionary;
+
+use Drupal\Core\Config\ConfigFactory;
+use Drupal\Core\Config\ImmutableConfig;
+use Drupal\metastore\DataDictionary\DataDictionaryDiscovery as Discovery;
+use MockChain\Chain;
+use MockChain\Options;
+use PHPUnit\Framework\TestCase;
+
+class DataDictionaryDiscoveryTest extends TestCase {
+
+
+  // If mode is set to "none", we should get NULL no matter what.
+  public function testModeNone() {
+    $configFactoryMock = $this->getConfigFactoryMock(Discovery::MODE_NONE, 'abc-123');
+    $discovery = new Discovery($configFactoryMock);
+    $id = $discovery->dictionaryIdFromResource('resource1');
+    $this->assertNull($id);
+  }
+
+  // If mode is sitewide, and we have a sitewide dictionary ID set, it should be
+  // returned, no matter what resource we pass to the method.
+  public function testSitewideId() {
+    $configFactoryMock = $this->getConfigFactoryMock(Discovery::MODE_SITEWIDE, 'abc-123');
+    $discovery = new Discovery($configFactoryMock);
+    $id = $discovery->dictionaryIdFromResource('resource1');
+    $this->assertEquals('abc-123', $id);
+    $idVersion = $discovery->dictionaryIdFromResource('resource1', '2352643');
+    $this->assertEquals('abc-123', $idVersion);
+  }
+
+  // If mode is sitewide but sitewide ID unset, we should get an exception.
+  public function testSitewideIdUnset() {
+    // Need to use 0 because MockChain\Options doesn't support NULL returns.
+    $configFactoryMock = $this->getConfigFactoryMock(Discovery::MODE_SITEWIDE, 0);
+    $discovery = new Discovery($configFactoryMock);
+
+    $this->expectException(\OutOfBoundsException::class);
+    $discovery->dictionaryIdFromResource('resource1');
+  }
+
+  // If mode is set to "collection", at the moment we should throw an exception
+  // because this is not yet supported.
+  public function testModeCollection() {
+    $configFactoryMock = $this->getConfigFactoryMock(Discovery::MODE_COLLECTION, 'abc-123');
+    $discovery = new Discovery($configFactoryMock);
+
+    $this->expectException(\OutOfRangeException::class);
+    $discovery->dictionaryIdFromResource('resource1');
+  }
+
+  // If mode is set to "generate", at the moment we should throw an exception
+  // because this is not yet supported.
+  public function testModeGenerate() {
+    $configFactoryMock = $this->getConfigFactoryMock(Discovery::MODE_GENERATE, 'abc-123');
+    $discovery = new Discovery($configFactoryMock);
+
+    $this->expectException(\OutOfRangeException::class);
+    $discovery->dictionaryIdFromResource('resource1');
+  }
+
+  // Build mock config service, based on arguments for mode and sitewide ID.
+  private function getConfigFactoryMock($mode, $sitewideId) {
+    $options = (new Options())
+      ->add('data_dictionary_mode', $mode)
+      ->add('data_dictionary_sitewide', $sitewideId)
+      ->index(0);
+
+    return (new Chain($this))
+      ->add(ConfigFactory::class, 'get', ImmutableConfig::class)
+      ->add(ImmutableConfig::class, 'get', $options)
+      ->getMock();
+  }
+}