Authorization Component

Registering the Authorization Component

The @loopback/authorization package exports an Authorization Component class.

• Developers will have to register this component to use access control features in their application.

  tsCopy

  const options: AuthorizationOptions = {
    precedence: AuthorizationDecision.DENY,
    defaultDecision: AuthorizationDecision.DENY,
  };
  
  app.configure(AuthorizationBindings.COMPONENT).to(options);
  app.component(AuthorizationComponent);
  

• The authorization options are provided specifically for enforcing the decision matrix, which is used to combine voters from all authorize functions. The options are described per the interface AuthorizationOptions.

  tsCopy

  export interface AuthorizationOptions {
    /**
     * Default decision if all authorizers vote for ABSTAIN
     */
    defaultDecision?: AuthorizationDecision.DENY | AuthorizationDecision.ALLOW;
    /**
     * Controls if Allow/Deny vote takes precedence and override other votes
     */
    precedence?: AuthorizationDecision.DENY | AuthorizationDecision.ALLOW;
  }
  

The component also declares various types to use in defining necessary classes and inputs by developers.

• Authorizer: A class implementing access policies. Accepts AuthorizationContext and AuthorizationMetadata as input and returns an AuthorizationDecision.

• AuthorizationDecision: expected type to be returned by an Authorizer

• AuthorizationMetadata: expected type of the authorization spec passed to the decorator used to annotate a controller method. Also provided as input parameter to the Authorizer.

• AuthorizationContext: contains current principal invoking an endpoint, request context and expected roles and scopes.

• Enforcer: type of extension classes that provide authorization services for an Authorizer.

• AuthorizationRequest: type of the input provided to an Enforcer.

• AuthorizationError: expected type of the error thrown by an Authorizer.