Issue #3446009 by andileco, nikathone: Make column selector a select list based on the headers

src/Plugin/views/field/ViewsCsvField.php

@@ -7,6 +7,7 @@ use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Render\Markup;
 use Drupal\views\Plugin\views\field\FieldPluginBase;
 use Drupal\views\ResultRow;
+use Drupal\views_csv_source\Plugin\views\query\ViewsCsvQuery;
 
 /**
  * Base field handler for views_csv_source.
@@ -66,13 +67,28 @@ class ViewsCsvField extends FieldPluginBase {
    */
   public function buildOptionsForm(&$form, FormStateInterface $form_state) {
     parent::buildOptionsForm($form, $form_state);
+
     $form['key'] = [
       '#title' => $this->t('Column Selector'),
       '#description' => $this->t('Choose a column'),
-      '#type' => 'textfield',
       '#default_value' => $this->options['key'],
       '#required' => TRUE,
     ];
+
+    // Get the query.
+    $query = $this->view->query;
+    assert($query instanceof ViewsCsvQuery, 'Query must be of type ViewsCsvQuery');
+
+    // Ensure the query is of the correct type.
+    if ($headers = $query->getCsvHeader()) {
+      $form['key']['#type'] = 'select';
+      $form['key']['#options'] = array_combine($headers, $headers);
+    }
+    else {
+      // Fall back to text value if CSV has not been selected.
+      $form['key']['#type'] = 'textfield';
+    }
+
     $form['trusted_html'] = [
       '#title' => $this->t('Trusted HTML'),
       '#description' => $this->t('This field is from a trusted source and contains raw HTML markup to render here. Use with caution.'),

src/Plugin/views/query/ViewsCsvQuery.php

@@ -607,6 +607,16 @@ class ViewsCsvQuery extends QueryPluginBase {
     return strtoupper($group_type);
   }
 
+  /**
+   * Get the CSV headers.
+   *
+   * @return array
+   *   The headers of the CSV file.
+   */
+  public function getCsvHeader(): array {
+    return $this->connection->getCsvHeader($this->getCsvFileUri());
+  }
+
   /**
    * Returns a list of non-aggregates to be added to the "group by" clause.
    *

src/Query/Connection.php

@@ -12,6 +12,8 @@ use Drupal\Core\Config\ImmutableConfig;
 use Drupal\views_csv_source\Event\PreCacheEvent;
 use Drupal\views_csv_source\UriParserTrait;
 use GuzzleHttp\Client;
+use GuzzleHttp\Exception\GuzzleException;
+use League\Csv\Reader;
 use Psr\Http\Message\ResponseInterface;
 
 /**
@@ -108,8 +110,6 @@ class Connection {
    *
    * @throws \Exception
    *   If the file is not found.
-   * @throws \GuzzleHttp\Exception\GuzzleException
-   *   If the request fails.
    */
   public function fetchContent(string $uri, array $options = []): string {
     if ($this->csvContent) {
@@ -141,11 +141,16 @@ class Connection {
       'cache_id' => Crypt::randomBytesBase64(),
     ];
 
-    // Add the request headers if available.
-    $result = $this->getRequestResponse($uri, $options);
+    try {
+      // Add the request headers if available.
+      $result = $this->getRequestResponse($uri, $options);
+    }
+    catch (GuzzleException $e) {
+      $result = NULL;
+    }
 
-    if (isset($result->error)) {
-      $message = sprintf('HTTP response: %s. URI: %s', $result->error, $uri);
+    if (isset($result->error) || $result === NULL) {
+      $message = sprintf('HTTP response: %s. URI: %s', $result->error ?? 'Unknown', $uri);
       throw new \Exception($message);
     }
 
@@ -163,6 +168,29 @@ class Connection {
     return $this->csvContent;
   }
 
+  /**
+   * Get the headers from the CSV file.
+   *
+   * @param string $uri
+   *   The URI of the CSV file.
+   *
+   * @return array
+   *   The headers of the CSV file.
+   */
+  public function getCsvHeader(string $uri = ''): array {
+    if (empty($uri)) {
+      $uri = $this->csvUri;
+    }
+
+    try {
+      $csv = Reader::createFromString($this->fetchContent($uri));
+      return $csv->nth(0) ?? [];
+    }
+    catch (\Exception $e) {
+      return [];
+    }
+  }
+
   /**
    * Get request result.
    *