IdentityModel 4 - Request custom grant

While updating my training material about OIDC I noticed that the documentation of IdentityServer didn’t reflect the latest changes in the IdentityModel library.

The example found in the documentation was still using the old TokenClient together with a RequestCustomGrantAsync() method:

	public async Task<TokenResponse> DelegateAsync(string userToken)
	{
	var payload = new
	{
	token = userToken
	};
	// create token client
	var client = new TokenClient(disco.TokenEndpoint, "api1.client", "secret");
	// send custom grant to token endpoint, return response
	return await client.RequestCustomGrantAsync("delegation", "api2", payload);
	}

view raw OldTokenClient.cs hosted with ❤ by GitHub

This method no longer exists in version 4 of IdentityModel. Instead you need to use the RequestTokenAsync() extension method on the HttpClient:

	public async Task<TokenResponse> DelegateAsync(string userToken)
	{
	// create client
	var client = _clientFactory.CreateClient();
	var disco = await client.GetDiscoveryDocumentAsync("https://localhost:44303/");
	// send custom grant to token endpoint, return response
	return await client.RequestTokenAsync(new TokenRequest
	{
	Address = disco.TokenEndpoint,
	GrantType = "delegation",
	ClientId = "api1.client",
	ClientSecret = "secret",
	Parameters =
	{
	{ "scope", "api2" },
	{ "token", userToken}
	},
	});
	}

view raw NewTokenClient.cs hosted with ❤ by GitHub