A DS.AdapterError is used by an adapter to signal that an error occurred during a request to an external API. It indicates a generic error, and subclasses are used to indicate specific error states. The following subclasses are provided:

• DS.InvalidError
• DS.TimeoutError
• DS.AbortError
• DS.UnauthorizedError
• DS.ForbiddenError
• DS.NotFoundError
• DS.ConflictError
• DS.ServerError

To create a custom error to signal a specific error state in communicating with an external API, extend the DS.AdapterError. For example if the external API exclusively used HTTP 503 Service Unavailable to indicate it was closed for maintenance:

import DS from 'ember-data';

export default DS.AdapterError.extend({ message: "Down for maintenance." });

This error would then be returned by an adapter's handleResponse method:

import DS from 'ember-data';
import MaintenanceError from './maintenance-error';

export default DS.JSONAPIAdapter.extend({
  handleResponse(status) {
    if (503 === status) {
      return new MaintenanceError();
    }

    return this._super(...arguments);
  }
});

And can then be detected in an application and used to send the user to an under-maintenance route:

import Ember from 'ember';
import MaintenanceError from '../adapters/maintenance-error';

export default Ember.Route.extend({
  actions: {
    error(error, transition) {
      if (error instanceof MaintenanceError) {
        this.transitionTo('under-maintenance');
        return;
      }

      // ...other error handling logic
    }
  }
});