Some suggested improvements for this module

search_api_solr_datasource.module

@@ -8,20 +8,10 @@
 use Drupal\search_api\IndexInterface;
 use Drupal\search_api\Query\QueryInterface;
 use Drupal\search_api\Query\ResultSetInterface;
+use Drupal\search_api_solr\Plugin\search_api\backend\SearchApiSolrBackend;
 use Solarium\QueryType\Select\Query\Query as SolariumQuery;
 use Solarium\QueryType\Select\Result\Result as SolariumResult;
 
-/**
- * Implements hook_search_api_field_type_mapping_alter().
- *
- * Add mappings for Solr data types to Search API data types.
- */
-function search_api_solr_datasource_search_api_field_type_mapping_alter(array &$mapping) {
-  $mapping['long'] = 'integer';
-  $mapping['tdate'] = 'date';
-  $mapping['text'] = 'text';
-}
-
 /**
  * Implements hook_search_api_solr_field_mapping_alter().
  *
@@ -55,7 +45,9 @@ function search_api_solr_datasource_search_api_solr_field_mapping_alter(IndexInt
   // Re-map the indexed fields.
   foreach ($fields as $raw => $name) {
     // Ignore the Search API fields.
-    if (strpos($raw, 'search_api_') === 0) {
+    if (strpos($raw, 'search_api_') === 0
+        || empty($index_fields[$raw])
+        || $index_fields[$raw]->getDatasourceId() !== 'solr_document') {
       continue;
     }
     $fields[$raw] = $index_fields[$raw]->getPropertyPath();
@@ -68,8 +60,8 @@ function search_api_solr_datasource_search_api_solr_field_mapping_alter(IndexInt
 function search_api_solr_datasource_search_api_solr_query_alter(SolariumQuery $solarium_query, QueryInterface $query) {
   // Do not alter the query if the index does not use the solr_document
   // datasource.
-  $datasources = $query->getIndex()->getDatasources();
-  if (!isset($datasources['solr_document'])) {
+  $index = $query->getIndex();
+  if (!$index->isValidDatasource('solr_document')) {
     return;
   }
 
@@ -78,9 +70,38 @@ function search_api_solr_datasource_search_api_solr_query_alter(SolariumQuery $s
   $solarium_query->removeFilterQuery('index_id');
 
   // Set requestHandler for the query type.
-  $config = $query->getIndex()->getDatasource('solr_document')->getConfiguration();
-  if (!empty($config['advanced']['request_handler'])) {
-    $solarium_query->addParam('qt', $config['advanced']['request_handler']);
+  $config = $index->getDatasource('solr_document')->getConfiguration();
+  if (!empty($config['request_handler'])) {
+    $solarium_query->addParam('qt', $config['request_handler']);
+  }
+
+  // Set the default query, if necessary and configured.
+  if (!$solarium_query->getQuery() && !empty($config['default_query'])) {
+    $solarium_query->setQuery($config['default_query']);
+  }
+
+  $backend = $index->getServerInstance()->getBackend();
+  if ($backend instanceof SearchApiSolrBackend) {
+    $solr_config = $backend->getConfiguration();
+    // @todo Should we maybe not even check that setting and use this to
+    //   auto-enable fields retrieval from Solr?
+    if (!empty($solr_config['retrieve_data'])) {
+      $fields_list = [];
+      foreach ($backend->getSolrFieldNames($index) as $solr_field_name) {
+        $fields_list[] = $solr_field_name;
+      }
+      $extra_fields = [
+        'language_field',
+        'label_field',
+        'url_field',
+      ];
+      foreach ($extra_fields as $config_key) {
+        if (!empty($config[$config_key])) {
+          $fields_list[] = $config[$config_key];
+        }
+      }
+      $solarium_query->setFields(array_unique($fields_list));
+    }
   }
 }
 

src/Plugin/DataType/SolrDocument.php

@@ -3,9 +3,11 @@
 namespace Drupal\search_api_solr_datasource\Plugin\DataType;
 
 use Drupal\Core\TypedData\ComplexDataInterface;
+use Drupal\Core\TypedData\Exception\MissingDataException;
 use Drupal\Core\TypedData\TypedData;
 use Drupal\search_api\Item\ItemInterface;
 use Drupal\search_api_solr_datasource\TypedData\SolrDocumentDefinition;
+use Solarium\QueryType\Select\Result\AbstractDocument;
 
 /**
  * Defines the "Solr document" data type.
@@ -66,14 +68,42 @@ public function get($property_name) {
     if (!isset($this->item)) {
       throw new MissingDataException("Unable to get Solr field $property_name as no item has been provided.");
     }
-    $field = $this->item->getField($property_name);
-    if ($field === NULL) {
-      throw new \InvalidArgumentException("The Solr field $property_name has not been configured in the index.");
-    }
-    // Create a new typed data object from the item's field data.
+
+    // First, verify that this field actually exists in the Solr server. If we
+    // can't get a definition for it, it doesn't exist.
     /** @var \Drupal\search_api_solr_datasource\Plugin\DataType\SolrField $plugin */
     $plugin = \Drupal::typedDataManager()->getDefinition('solr_field')['class'];
-    return $plugin::createFromField($field, $property_name, $this);
+    $field_manager = \Drupal::getContainer()->get('solr_field.manager');
+    $server_id = $this->item->getIndex()->getServerInstance()->id();
+    $fields = $field_manager->getFieldDefinitions($server_id);
+    if (empty($fields[$property_name])) {
+      throw new \InvalidArgumentException("The Solr field $property_name could not be found on the $server_id server.");
+    }
+    // Create a new typed data object from the item's field data.
+    $property = $plugin::createInstance($fields[$property_name], $property_name, $this);
+
+    // Now that we have the property, try to find its values. We first look at
+    // the field values contained in the result item.
+    $found = FALSE;
+    foreach ($this->item->getFields(FALSE) as $field) {
+      if ($field->getDatasourceId() === 'solr_document'
+          && $field->getPropertyPath() === $property_name) {
+        $property->setValue($field->getValues());
+        $found = TRUE;
+        break;
+      }
+    }
+
+    if (!$found) {
+      // If that didn't work, maybe we can get the field from the Solr document?
+      $document = $this->item->getExtraData('search_api_solr_document');
+      if ($document instanceof AbstractDocument
+          && isset($document[$property_name])) {
+        $property->setValue($document[$property_name]);
+      }
+    }
+
+    return $property;
   }
 
   /**

src/Plugin/DataType/SolrField.php

@@ -22,11 +22,11 @@
 class SolrField extends TypedData implements \IteratorAggregate, TypedDataInterface {
 
   /**
-   * The wrapped Search API Field.
+   * The field value(s).
    *
-   * @var \Drupal\search_api\Item\FieldInterface|null
+   * @var mixed
    */
-  protected $field;
+  protected $value;
 
   /**
    * Creates an instance wrapping the given Field.
@@ -45,36 +45,18 @@ public static function createFromField(FieldInterface $field, $name, TypedDataIn
     /** @var \Drupal\search_api_solr_datasource\SolrFieldManagerInterface $field_manager */
     $field_manager = \Drupal::getContainer()->get('solr_field.manager');
     $server_id = $field->getIndex()->getServerInstance()->id();
-    $field_id = $field->getFieldIdentifier();
+    $field_id = $field->getPropertyPath();
     $definition = $field_manager->getFieldDefinitions($server_id)[$field_id];
     $instance = new static($definition, $name, $parent);
-    $instance->setValue($field);
+    $instance->setValue($field->getValues());
     return $instance;
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function getValue() {
-    return $this->field;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setValue($field, $notify = TRUE) {
-    $this->field = $field;
-    // Notify the parent of any changes.
-    if ($notify && isset($this->parent)) {
-      $this->parent->onChange($this->name);
-    }
-  }
-
   /**
    * {@inheritdoc}
    */
   public function getIterator() {
-    return isset($this->field) ? $this->field->getIterator() : new \ArrayIterator([]);
+    return new \ArrayIterator((array) $this->value);
   }
 
 }