qbit-printing/dev/client/DiscoveryChecks.cs

// Copyright 2026 Kingsrook, LLC

// SPDX-License-Identifier: Apache-2.0
using System.Net;
using System.Text.Json;
using Qqq.PrintAgent.Core.Authentication;

internal static class DiscoveryChecks
{
   internal static async Task RunAsync()
   {
      (string Version, bool Accepted)[] cases =
      [
         ("2.0.0", true), ("2.1.0", true), ("2.9.17", true),
         ("1.9.0", false), ("3.0.0", false), ("2.1", false),
         ("2.01.0", false), ("2.1.0-rc.1", false), ("not-a-version", false)
      ];
      foreach((string version, bool expected) in cases)
      {
         using var handler = new DiscoveryHandler(version);
         using var client = new QqqSessionClient(new Uri("https://printing.example.invalid"), handler);
         bool accepted = false;
         try
         {
            await WorkloadDiscovery.DiscoverRealtimeAsync(client, CancellationToken.None);
            accepted = true;
         }
         catch(QqqSessionException error) when(error.Failure == QqqSessionException.FailureKind.ConfigurationRequired) { }
         catch(InvalidDataException) { }
         if(accepted != expected || handler.Requests != 1)
         {
            throw new InvalidDataException($"Discovery compatibility case {version} failed.");
         }
      }
      Console.WriteLine($"Discovery compatibility checks passed: {cases.Length}.");
   }

   private sealed class DiscoveryHandler(string version) : HttpMessageHandler
   {
      internal int Requests { get; private set; }

      protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
      {
         if(request.Method != HttpMethod.Get || request.RequestUri?.AbsolutePath != "/qqq/v1/version"
            || request.Headers.Contains("Cookie") || request.Headers.Contains("Authorization"))
         {
            throw new InvalidOperationException("Discovery must precede authentication.");
         }
         Requests++;
         string json = JsonSerializer.Serialize(new
         {
            apiVersion = "1.8.0",
            features = new[] { "version", "metaData", "processes", "processCancel", "extensions", "widgets" },
            clientChannels = new[] { "api" },
            extensions = new[] { new { name = "printing", version, pathPrefix = "/qbit/printing" } }
         });
         return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK) { Content = new StringContent(json) });
      }
   }
}