/// <inheritdoc />
public async Task <OAuth2Token> FetchToken(CancellationToken ct = default)
{
var token = await tokenStorage.GetTokeAsync().ConfigureAwait(false);
if (token == null)
{
logger.LogTrace("No stored token found.");
return(null);
}
if (!token.IsExpired)
{
logger.LogTrace("Existing token returned.");
return(token);
}
try
{
semaphore.Wait(ct);
logger.LogTrace("Try refresh token.");
token = await authenticator.RefreshTokenAsync(token, ct)
.ConfigureAwait(false);
await tokenStorage.AddTokenAsync(token).ConfigureAwait(false);
return(token);
}
catch (Exception exception)
{
logger.LogError("Failed refresh token: {Message}", exception.Message);
await tokenStorage.AddTokenAsync(null).ConfigureAwait(false);
return(null);
}
finally
{
semaphore.Release();
}
}