Use C# to Invoke Open API (WebAPI)¶

using System.Net.Http.Headers;
using System.Net.Http.Json;

var baseUrl = "https://localhost:8043";
var clientId = "your_client_id";
var clientSecret = "your_client_secret";

using var httpHandler = new HttpClientHandler
{
    // For local development only. Use trusted certificates in production.
    ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator
};
using var http = new HttpClient(httpHandler)
{
    BaseAddress = new Uri(baseUrl)
};

// 1) Discover token endpoint
var openIdConfigUrl = $"{baseUrl}/.well-known/openid-configuration";
var openIdDoc = await http.GetFromJsonAsync<OpenIdConfiguration>(openIdConfigUrl)
    ?? throw new InvalidOperationException("Failed to load OpenID metadata.");

if (string.IsNullOrWhiteSpace(openIdDoc.token_endpoint))
{
    throw new InvalidOperationException("token_endpoint is missing in OpenID metadata.");
}

// 2) Request access token (client credentials)
using var tokenResponse = await http.PostAsync(
    openIdDoc.token_endpoint,
    new FormUrlEncodedContent(new Dictionary<string, string>
    {
        ["client_id"] = clientId,
        ["client_secret"] = clientSecret,
        ["grant_type"] = "client_credentials"
    }));

tokenResponse.EnsureSuccessStatusCode();

var tokenPayload = await tokenResponse.Content.ReadFromJsonAsync<TokenResponse>()
    ?? throw new InvalidOperationException("Token response is empty.");

if (string.IsNullOrWhiteSpace(tokenPayload.access_token))
{
    throw new InvalidOperationException("access_token is missing in token response.");
}

// 3) Attach bearer token to all WebAPI calls
http.DefaultRequestHeaders.Authorization =
    new AuthenticationHeaderValue("Bearer", tokenPayload.access_token);

// 4) Example A: Query asset instances
var parentPath = Uri.EscapeDataString("Default");
using var getResponse = await http.GetAsync($"/api/v1/assetInstances?parentPath={parentPath}");
getResponse.EnsureSuccessStatusCode();

var getJson = await getResponse.Content.ReadAsStringAsync();
Console.WriteLine("GET /api/v1/assetInstances response:");
Console.WriteLine(getJson);

// 5) Example B: Create an asset instance
var createPayload = new
{
    parentPath = "Default",
    name = "demo_instance_from_openapi",
    modelPath = "Default:DemoModel"
};

using var postResponse = await http.PostAsJsonAsync("/api/v1/assetInstances", createPayload);
postResponse.EnsureSuccessStatusCode();

var postJson = await postResponse.Content.ReadAsStringAsync();
Console.WriteLine("POST /api/v1/assetInstances response:");
Console.WriteLine(string.IsNullOrWhiteSpace(postJson) ? "(empty body)" : postJson);

record OpenIdConfiguration(string token_endpoint);
record TokenResponse(string access_token, string token_type, int expires_in);