Allow a remote file as the Source path

src/Plugin/migrate/source/CSV.php

@@ -197,6 +197,10 @@ class CSV extends SourcePluginBase implements ConfigurableInterface {
    * @throws \League\Csv\Exception
    */
   public function initializeIterator() {
+    if (preg_match('/^https?:\/\//', $this->configuration['path'])) {
+      $this->configuration['path'] = $this->downloadRemoteFileToTmp($this->configuration['path']);
+    }
+
     $header = $this->getReader()->getHeader();
     if ($this->configuration['fields']) {
       // If there is no header record, we need to flip description and name so
@@ -292,4 +296,51 @@ class CSV extends SourcePluginBase implements ConfigurableInterface {
     return Reader::createFromStream($csv);
   }
 
+  /**
+   * Download a remote file to a temporary file to be streamed by the Reader.
+   *
+   * @param $remote_path
+   *   The remote path to download.
+   *
+   * @return string
+   *   The path to the temporary file.
+   */
+  protected function downloadRemoteFileToTmp($remote_path): string {
+    // Get the last modified time of the remote file.
+    $ch = curl_init($remote_path);
+    curl_setopt($ch, CURLOPT_NOBODY, TRUE);
+    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
+    curl_setopt($ch, CURLOPT_FILETIME, TRUE);
+    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
+    curl_exec($ch);
+    $remote_last_modified = curl_getinfo($ch, CURLINFO_FILETIME);
+    curl_close($ch);
+
+    if ($remote_last_modified === -1) {
+      throw new \RuntimeException(sprintf('Could not retrieve the last modified time for "%s".', $remote_path));
+    }
+
+    $file_name = pathinfo($remote_path, PATHINFO_FILENAME);
+    $tmp_csv_file = sys_get_temp_dir() . '/csv_' . $file_name . '_' . $remote_last_modified;
+
+    if (!file_exists($tmp_csv_file)) {
+      $fp = fopen($tmp_csv_file, 'w+');
+
+      $ch = curl_init($remote_path);
+      curl_setopt($ch, CURLOPT_FILE, $fp);
+      curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
+      curl_setopt($ch, CURLOPT_FAILONERROR, TRUE);
+
+      $result = curl_exec($ch);
+      if ($result === FALSE) {
+        throw new \RuntimeException(sprintf('File "%s" could not be downloaded. cURL error: %s', $remote_path, curl_error($ch)));
+      }
+
+      curl_close($ch);
+      fclose($fp);
+    }
+
+    return $tmp_csv_file;
+  }
+
 }