Providers

Providers are the core components that handle authentication and transaction signing in the FastAuth Browser SDK. They implement the IFastAuthProvider interface and manage the communication between your application and the authentication backend.

FastAuthProvider Interface

The IFastAuthProvider interface defines the contract that all providers must implement. It extends the signer provider interface and adds authentication-specific methods.

Interface Definition

interface IFastAuthProvider {
    // Authentication methods
    login(...args: any[]): void;
    logout(): void;
    isLoggedIn(): Promise<boolean>;

    // Transaction signing methods
    requestTransactionSignature(...args: any[]): Promise<void>;
    requestDelegateActionSignature(...args: any[]): Promise<void>;

    // Utility methods
    getSignatureRequest(): Promise<SignatureRequest>;
    getPath(): Promise<string>;
}

Methods

Authentication Methods

• login(...args: any[]): void

  • Initiates the login process for the user
  • Implementation varies by provider (e.g., redirect, popup, etc.)

• logout(): void

  • Logs out the current user and clears session data

• isLoggedIn(): Promise<boolean>

  • Returns whether the user is currently authenticated
  • Should handle URL callback parameters and session validation

Transaction Signing Methods

• requestTransactionSignature(...args: any[]): Promise<void>

  • Requests a signature for a NEAR transaction
  • Typically redirects to the authentication provider for approval

• requestDelegateActionSignature(...args: any[]): Promise<void>

  • Requests a signature for a delegate action
  • Used for meta-transactions and sponsored transactions

Utility Methods

• getSignatureRequest(): Promise<SignatureRequest>

  • Retrieves the signature request data after authentication
  • Returns an object with guardId, verifyPayload, and signPayload

• getPath(): Promise<string>

  • Returns the derivation path for the user's account
  • Used to generate deterministic account addresses

SignatureRequest Type

type SignatureRequest = {
    guardId: string; // Identifier for the guard contract
    verifyPayload: string; // JWT or verification data
    signPayload: Uint8Array; // Transaction data to be signed
    algorithm?: MPCContractAlgorithm; // Optional algorithm specification
};

type MPCContractAlgorithm = "secp256k1" | "eddsa" | "ecdsa";