Importing SF attachments (Help!)

I was able to retrieve a file from the ContentVersion object using PHP and cURL with this code snippet. It is using the Drupal 7 Salesforce Suite module.

<?php

  $fullUrl = 'https://test.sandbox.my.salesforce.com/services/data/v60.0/sobjects/ContentVersion/' . $salesforce_entity_id . '/VersionData';
  
  $accessToken = $sfapi->getAccessToken();    

  // Use cURL to make the GET request

  $ch = curl_init($fullUrl);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Authorization: Bearer ' . $accessToken,
    'Content-type: application/json',
  ));
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true); // Follow redirects
  curl_setopt($ch, CURLOPT_FAILONERROR, true); // Report HTTP code > 400 as error
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // Do not verify SSL certificate
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // Return the transfer as a string
  $image_data = curl_exec($ch);

  $directory = 'private://imagefiles/';


  $uri = $directory .  basename($title) . '.' . $filename; // Set the filename

  // Save the file data to the specified location
  $saved_file = file_save_data($image_data, $uri, FILE_EXISTS_REPLACE);

  // Save the file to the Drupal file system
  // $saved_file  = file_save($file);

  // Check if the file was saved successfully
  if ($saved_file) {
    drupal_set_message("The file has been saved successfully.");
  } else {
    drupal_set_message("There was an error saving the file.", 'error');
  }

  // Check for errors
  if (curl_errno($ch)) {
    $error_msg = curl_error($ch);
    ds($error_msg, 'cURL Error');
  }
  // Check if the request was successful and write the file
  curl_close($ch);
?>