constants.js

/**
 * @typedef {string} UpdateType - a type of push notification as defined by
 * the [Google Drive API docs](https://bit.ly/3wcsY2X)
 */

/**
 * A new channel was successfully created. You can expect to start receiving
 * notifications for it.
 *
 * @type {UpdateType}
 */
const GOOGLE_DRIVE_NOTIFICATION_SYNC = "sync";

/**
 * A new resource was created or shared
 *
 * @type {UpdateType}
 */
const GOOGLE_DRIVE_NOTIFICATION_ADD = "add";

/**
 * An existing resource was deleted or unshared
 *
 * @type {UpdateType}
 */
const GOOGLE_DRIVE_NOTIFICATION_REMOVE = "remove";

/**
 * One or more properties (metadata) of a resource have been updated
 *
 * @type {UpdateType}
 */
const GOOGLE_DRIVE_NOTIFICATION_UPDATE = "update";

/**
 * A resource has been moved to the trash
 *
 * @type {UpdateType}
 */
const GOOGLE_DRIVE_NOTIFICATION_TRASH = "trash";

/**
 * A resource has been removed from the trash
 *
 * @type {UpdateType}
 */
const GOOGLE_DRIVE_NOTIFICATION_UNTRASH = "untrash";

/**
 * One or more new changelog items have been added
 *
 * @type {UpdateType}
 */
const GOOGLE_DRIVE_NOTIFICATION_CHANGE = "change";

/**
 * All the available Google Drive update types
 * @type {UpdateType[]}
 */
const GOOGLE_DRIVE_UPDATE_TYPES = [
  GOOGLE_DRIVE_NOTIFICATION_SYNC,
  GOOGLE_DRIVE_NOTIFICATION_ADD,
  GOOGLE_DRIVE_NOTIFICATION_REMOVE,
  GOOGLE_DRIVE_NOTIFICATION_UPDATE,
  GOOGLE_DRIVE_NOTIFICATION_TRASH,
  GOOGLE_DRIVE_NOTIFICATION_UNTRASH,
  GOOGLE_DRIVE_NOTIFICATION_CHANGE,
];

/**
 * This is a custom string value to represent the 'My Drive' Google Drive, which
 * is represented as `null` by the Google Drive API. In order to simplify the
 * code by avoiding null values, we assign this special value to the 'My Drive'
 * drive.
 */
const MY_DRIVE_VALUE = "myDrive";

/**
 * The maximum amount of time a subscription can be active without expiring is
 * 24 hours. In order to minimize subscription renewals (which involve the
 * execution of an event source) we set the expiration of subscriptions to its
 * maximum allowed value.
 *
 * More information can be found in the API docs:
 * https://developers.google.com/drive/api/v3/push#optional-properties
 */
const WEBHOOK_SUBSCRIPTION_EXPIRATION_TIME_MILLISECONDS = 24 * 60 * 60 * 1000;

/**
 * The default time interval between webhook subscription renewals. Since
 * subscriptions expire after 24 hours at most, we set this time to 95% of this
 * time window by default to make sure the event sources don't miss any events
 * due to an expired subscription not being renewed on time.
 *
 * More information can be found in the API docs:
 * https://developers.google.com/drive/api/v3/push#optional-properties
 */
const WEBHOOK_SUBSCRIPTION_RENEWAL_SECONDS = (
  WEBHOOK_SUBSCRIPTION_EXPIRATION_TIME_MILLISECONDS * .95 / 1000
);

module.exports = {
  GOOGLE_DRIVE_NOTIFICATION_SYNC,
  GOOGLE_DRIVE_NOTIFICATION_ADD,
  GOOGLE_DRIVE_NOTIFICATION_REMOVE,
  GOOGLE_DRIVE_NOTIFICATION_UPDATE,
  GOOGLE_DRIVE_NOTIFICATION_TRASH,
  GOOGLE_DRIVE_NOTIFICATION_UNTRASH,
  GOOGLE_DRIVE_NOTIFICATION_CHANGE,
  GOOGLE_DRIVE_UPDATE_TYPES,
  MY_DRIVE_VALUE,
  WEBHOOK_SUBSCRIPTION_EXPIRATION_TIME_MILLISECONDS,
  WEBHOOK_SUBSCRIPTION_RENEWAL_SECONDS,
};