Use C# to Invoke Realtime Data API (SignalR)¶

using System.Net.Http.Json;
using System.Text.Json;
using Microsoft.AspNetCore.SignalR.Client;

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

// Tag paths to subscribe
var tagPaths = new[]
{
    "Default:m1",
    "Default:m2",
    "Default:m3"
};

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

// 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) Connect realtime endpoint
var hubUrl = $"{baseUrl}/ws/v1/realtimeData";
var connection = new HubConnectionBuilder()
    .WithUrl(hubUrl, options =>
    {
        options.AccessTokenProvider = () => Task.FromResult(tokenPayload.access_token)!;
        options.HttpMessageHandlerFactory = handler =>
        {
            if (handler is HttpClientHandler h)
            {
                // For local development only. Use trusted certificates in production.
                h.ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator;
            }

            return handler;
        };
    })
    .WithAutomaticReconnect()
    .Build();

connection.Closed += error =>
{
    Console.WriteLine($"Connection closed: {error?.Message}");
    return Task.CompletedTask;
};

await connection.StartAsync();
Console.WriteLine("Connected to realtimeData hub.");

// 4) Stream tag values from target: TagValues
await foreach (var batch in connection.StreamAsync<List<TagValue>>("TagValues", tagPaths))
{
    foreach (var item in batch)
    {
        Console.WriteLine($"{item.path} = {item.value} ({item.quality}) @ {item.time:O}");
    }
}

record OpenIdConfiguration(string token_endpoint);

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

record TagValue(string path, JsonElement value, DateTimeOffset time, string quality);