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The Simple OAuth module is used to provide an OAuth2 standard authorization server.

For documentation on using and authenticating with the farmOS API see API.

Providing OAuth Clients

OAuth clients are modeled as "Consumer" entities (provided by the Consumers module. The farm_api module provides a default client with client_id = farm. This can be used for general usage of the API, but comes with limitations. To create a third party integration with farmOS a consumer entity must be created that identifies the integration and configures the OAuth Client authorization behavior.


OAuth scopes define different levels of permission. OAuth clients are configured with the scopes needed for the purposes of a specific integration. With consumers, these scopes are implemented as Drupal Roles. This means that OAuth clients interacting with farmOS over the API use the same permission system as Users normally using the site.

Client Configuration

Standard Consumer configuration:

  • consumer.label - A label used to identify the third party integration.
  • consumer.client_id - An optional client_id machine name to identify the consumer. The simple_oauth module uses a UUID by default, but a machine name makes it easier to identify clients across multiple farmOS servers.
  • consumer.secret - A client_secret used to secure the OAuth client.
  • consumer.confidential - A boolean indicating whether the client secret needs to be validated.
    • Most farmOS third party integrations will disable this. Otherwise the same client_secret must be configured on all farmOS servers, or the third party must keep track of a different secret for each server. This challenge is due to the nature of farmOS being a self-hosted application.
  • consumer.user_id - When no specific user is authenticated Drupal will use this user as the author of all the actions made by this consumer.
    • This is only the case during the Client Credentials authorization flow.
  • consumer.redirect_uri - The URI this client will redirect to when needed.
    • This is used with the Authorization Code authorization flow.
  • consumer.allowed_origins - Define any allowed origins the farmOS server should allow CORS requests from. This is required for any API integrations that will run in the browser.
  • consumer.third_party - Enable if the Consumer represents a third party.
    • Users will skip the "grant" step of the authorization flow for first party consumers only.

farmOS extends the consumers and simple_oauth modules to provide additional authorization options on consumer entities. These additional options make it possible to support different third party integration use cases via the same OAuth Authorization server. They can be configured via the UI or when creating a consumer entity programmatically.

Authorization options (all are disabled by default):

  • consumer.grant_user_access - Always grant the authorizing user's access to this consumer.
    • This is how the farmOS Field Kit consumer is configured. If this is the only option enabled, then the consumer will only be granted the roles the user has access to.
  • consumer.limit_requested_access - Only grant this consumer the scopes requested during authorization.
    • By default, all scopes configured with the consumer will be granted during authorization. This allows users to select which scopes they want to grant the third party during authorization.
  • consumer.limit_user_access - Never grant the consumer more access than the authorizing user.
    • It is possible that clients will be configured with different roles than the user that authorizes access to a third party. There are times that this may be intentional, but this setting ensures that consumers will not be granted more access than the authorizing user.