Henara.MetabaseEmbed.Client

Client for the Henara Metabase token service (gRPC). Exchanges the user's Keycloak access token for Metabase embed tokens and lists the dashboards the user may embed.

Setup

Sign-in is up to the host. Register the client; the options are bound from the host's IConfiguration, which reads the environment variables:

services.AddMetabaseEmbed(configuration);

The Keycloak access token reaches the client in one of two ways:

• Pass it to each call: GetAccessibleDashboardsAsync(accessToken), GetEmbedTokenAsync(accessToken, databaseId, type), or the AccessToken parameter of the dashboard components. Nothing else needs to be registered.
• Or register an IKeycloakAccessTokenProvider and call the overloads without a token:

public sealed class KeycloakAccessTokenProvider : IKeycloakAccessTokenProvider
{
    private readonly MyTokenStore _tokens;

    public KeycloakAccessTokenProvider(MyTokenStore tokens) => _tokens = tokens;

    public Task<string?> GetAccessTokenAsync(CancellationToken ct = default) => _tokens.GetAccessTokenAsync(ct);
}

services.AddSingleton<IKeycloakAccessTokenProvider, KeycloakAccessTokenProvider>();

A passed token is used even when a provider is registered.

All are required. AddMetabaseEmbed validates them immediately and throws OptionsValidationException when one is missing or invalid, in any host (ASP.NET Core, MAUI, WPF, Windows Forms).

The optional second argument changes the options after binding, before validation:

services.AddMetabaseEmbed(configuration, options =>
    options.CreateHttpHandler = () => new GrpcWebHandler(GrpcWebMode.GrpcWeb, new HttpClientHandler()));

CreateHttpHandler sets the HTTP handler of the token service channel. Register an IGrpcAddressProvider before AddMetabaseEmbed to resolve the address at runtime.

Usage

Inject IMetabaseTokenProvider:

var dashboards = await tokenProvider.GetAccessibleDashboardsAsync(accessToken);
var token = await tokenProvider.GetEmbedTokenAsync(accessToken, databaseId, DashboardType.MeinePraxis);

With a registered IKeycloakAccessTokenProvider, omit accessToken.

Errors

Failures throw MetabaseTokenServiceException with the server's message and a Reason:

Cancelling the CancellationToken throws OperationCanceledException.