Function fetchToken

src/client/auth.ts:1381–1427

(
    provider: OAuthClientProvider,
    authorizationServerUrl: string | URL,
    {
        metadata,
        resource,
        authorizationCode,
        fetchFn
    }: {
        metadata?: AuthorizationServerMetadata;
        resource?: URL;
        /** Authorization code for the default authorization_code grant flow */
        authorizationCode?: string;
        fetchFn?: FetchLike;
    } = {}
)

 * const tokens = await fetchToken(provider, authServerUrl, { metadata });
 */
export async function fetchToken(
    provider: OAuthClientProvider,
    authorizationServerUrl: string | URL,
    {
        metadata,
        resource,
        authorizationCode,
        fetchFn
    }: {
        metadata?: AuthorizationServerMetadata;
        resource?: URL;
        /** Authorization code for the default authorization_code grant flow */
        authorizationCode?: string;
        fetchFn?: FetchLike;
    } = {}
): Promise<OAuthTokens> {
    const scope = provider.clientMetadata.scope;

    // Use provider's prepareTokenRequest if available, otherwise fall back to authorization_code
    let tokenRequestParams: URLSearchParams | undefined;
    if (provider.prepareTokenRequest) {
        tokenRequestParams = await provider.prepareTokenRequest(scope);
    }

    // Default to authorization_code grant if no custom prepareTokenRequest
    if (!tokenRequestParams) {
        if (!authorizationCode) {
            throw new Error('Either provider.prepareTokenRequest() or authorizationCode is required');
        }
        if (!provider.redirectUrl) {
            throw new Error('redirectUrl is required for authorization_code flow');
        }
        const codeVerifier = await provider.codeVerifier();
        tokenRequestParams = prepareAuthorizationCodeRequest(authorizationCode, codeVerifier, provider.redirectUrl);
    }

    const clientInformation = await provider.clientInformation();

    return executeTokenRequest(authorizationServerUrl, {
        metadata,
        tokenRequestParams,
        clientInformation: clientInformation ?? undefined,
        addClientAuthentication: provider.addClientAuthentication,
        resource,
        fetchFn
    });
}

/**
 * Performs OAuth 2.0 Dynamic Client Registration according to RFC 7591.