Remove HttpClient abstractions

Now implement mocked `HttpMessageHandler`s as recommended: https://stackoverflow.com/a/36427274/3976486

src/Tgstation.Server.Client/ApiClient.cs

@@ -69,9 +69,9 @@ namespace Tgstation.Server.Client
 		};
 
 		/// <summary>
-		/// The <see cref="IHttpClient"/> for the <see cref="ApiClient"/>.
+		/// The <see cref="HttpClient"/> for the <see cref="ApiClient"/>.
 		/// </summary>
-		readonly IHttpClient httpClient;
+		readonly HttpClient httpClient;
 
 		/// <summary>
 		/// The <see cref="IRequestLogger"/>s used by the <see cref="ApiClient"/>.
@@ -166,7 +166,7 @@ namespace Tgstation.Server.Client
 		/// <param name="tokenRefreshHeaders">The value of <see cref="tokenRefreshHeaders"/>.</param>
 		/// <param name="authless">The value of <see cref="authless"/>.</param>
 		public ApiClient(
-			IHttpClient httpClient,
+			HttpClient httpClient,
 			Uri url,
 			ApiHeaders apiHeaders,
 			ApiHeaders? tokenRefreshHeaders,

src/Tgstation.Server.Client/ApiClientFactory.cs

@@ -1,7 +1,7 @@
 using System;
+using System.Net.Http;
 
 using Tgstation.Server.Api;
-using Tgstation.Server.Common.Http;
 
 namespace Tgstation.Server.Client
 {
@@ -19,5 +19,19 @@ namespace Tgstation.Server.Client
 				apiHeaders,
 				tokenRefreshHeaders,
 				authless);
+
+		/// <inheritdoc />
+		public IApiClient CreateApiClient(
+			Uri url,
+			ApiHeaders apiHeaders,
+			ApiHeaders? tokenRefreshHeaders,
+			HttpMessageHandler handler,
+			bool disposeHandler,
+			bool authless) => new ApiClient(
+				new HttpClient(handler, disposeHandler),
+				url,
+				apiHeaders,
+				tokenRefreshHeaders,
+				authless);
 	}
 }

src/Tgstation.Server.Client/IApiClientFactory.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net.Http;
 
 using Tgstation.Server.Api;
 
@@ -22,5 +23,23 @@ namespace Tgstation.Server.Client
 			ApiHeaders apiHeaders,
 			ApiHeaders? tokenRefreshHeaders,
 			bool authless);
+
+		/// <summary>
+		/// Create an <see cref="IApiClient"/>.
+		/// </summary>
+		/// <param name="url">The base <see cref="Uri"/>.</param>
+		/// <param name="apiHeaders">The <see cref="ApiHeaders"/> for the <see cref="IApiClient"/>.</param>
+		/// <param name="tokenRefreshHeaders">The <see cref="ApiHeaders"/> to use to generate a new <see cref="Api.Models.Response.TokenResponse"/>.</param>
+		/// <param name="handler">The <see cref="HttpMessageHandler"/> to use with the internal <see cref="HttpClient"/>.</param>
+		/// <param name="disposeHandler">If <paramref name="handler"/> should be disposed with the created <see cref="IApiClient"/>.</param>
+		/// <param name="authless">If there should be no authentication performed.</param>
+		/// <returns>A new <see cref="IApiClient"/>.</returns>
+		public IApiClient CreateApiClient(
+			Uri url,
+			ApiHeaders apiHeaders,
+			ApiHeaders? tokenRefreshHeaders,
+			HttpMessageHandler handler,
+			bool disposeHandler,
+			bool authless);
 	}
 }

src/Tgstation.Server.Common/Http/CachedResponseStream.cs

@@ -36,7 +36,7 @@ namespace Tgstation.Server.Common.Http
 				response.Content = null;
 				try
 				{
-					// don't cry about the missing CancellationToken overload: https://github.com/dotnet/runtime/issues/916
+					// don't cry about the missing CancellationToken overload: https://github.com/dotnet/corefx/issues/32615#issuecomment-562083237
 					var responseStream = await content.ReadAsStreamAsync().ConfigureAwait(false);
 					return new CachedResponseStream(content, responseStream);
 				}

src/Tgstation.Server.Common/Http/HttpClient.cs

@@ -1,51 +0,0 @@
-using System;
-using System.Net.Http;
-using System.Net.Http.Headers;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace Tgstation.Server.Common.Http
-{
-	/// <inheritdoc />
-	public sealed class HttpClient : IHttpClient
-	{
-		/// <inheritdoc />
-		public TimeSpan Timeout
-		{
-			get => httpClient.Timeout;
-			set => httpClient.Timeout = value;
-		}
-
-		/// <inheritdoc />
-		public HttpRequestHeaders DefaultRequestHeaders => httpClient.DefaultRequestHeaders;
-
-		/// <summary>
-		/// The real <see cref="System.Net.Http.HttpClient"/>.
-		/// </summary>
-		readonly System.Net.Http.HttpClient httpClient;
-
-		/// <summary>
-		/// Initializes a new instance of the <see cref="HttpClient"/> class.
-		/// </summary>
-		/// <param name="implementation">The <see cref="System.Net.Http.HttpClient"/> to wrap.</param>
-		public HttpClient(System.Net.Http.HttpClient implementation)
-		{
-			httpClient = implementation ?? throw new ArgumentNullException(nameof(implementation));
-		}
-
-		/// <summary>
-		/// Initializes a new instance of the <see cref="HttpClient"/> class.
-		/// </summary>
-		public HttpClient()
-			: this(new System.Net.Http.HttpClient())
-		{
-		}
-
-		/// <inheritdoc />
-		public void Dispose() => httpClient.Dispose();
-
-		/// <inheritdoc />
-		public Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)
-			=> httpClient.SendAsync(request, completionOption, cancellationToken);
-	}
-}

src/Tgstation.Server.Common/Http/HttpClientFactory.cs

@@ -1,41 +0,0 @@
-using System;
-using System.Net.Http.Headers;
-
-namespace Tgstation.Server.Common.Http
-{
-	/// <summary>
-	/// <see cref="IAbstractHttpClientFactory"/> that creates <see cref="HttpClient"/>s.
-	/// </summary>
-	public sealed class HttpClientFactory : IAbstractHttpClientFactory
-	{
-		/// <inheritdoc />
-		public IHttpClient CreateClient()
-		{
-			var client = new HttpClient();
-			try
-			{
-				client.DefaultRequestHeaders.UserAgent.Add(userAgent);
-				return client;
-			}
-			catch
-			{
-				client.Dispose();
-				throw;
-			}
-		}
-
-		/// <summary>
-		/// The <see cref="ProductInfoHeaderValue"/> used as created client's User-Agent header on request.
-		/// </summary>
-		readonly ProductInfoHeaderValue userAgent;
-
-		/// <summary>
-		/// Initializes a new instance of the <see cref="HttpClientFactory"/> class.
-		/// </summary>
-		/// <param name="userAgent">The value of <see cref="userAgent"/>.</param>
-		public HttpClientFactory(ProductInfoHeaderValue userAgent)
-		{
-			this.userAgent = userAgent ?? throw new ArgumentNullException(nameof(userAgent));
-		}
-	}
-}

src/Tgstation.Server.Common/Http/IAbstractHttpClientFactory.cs

@@ -1,14 +0,0 @@
-namespace Tgstation.Server.Common.Http
-{
-	/// <summary>
-	/// Creates <see cref="IHttpClient"/>s.
-	/// </summary>
-	public interface IAbstractHttpClientFactory
-	{
-		/// <summary>
-		/// Create a <see cref="IHttpClient"/>.
-		/// </summary>
-		/// <returns>A new <see cref="IHttpClient"/>.</returns>
-		IHttpClient CreateClient();
-	}
-}

src/Tgstation.Server.Common/Http/IHttpClient.cs

@@ -1,33 +0,0 @@
-using System;
-using System.Net.Http;
-using System.Net.Http.Headers;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace Tgstation.Server.Common.Http
-{
-	/// <summary>
-	/// For sending HTTP requests.
-	/// </summary>
-	public interface IHttpClient : IDisposable
-	{
-		/// <summary>
-		/// The request timeout.
-		/// </summary>
-		TimeSpan Timeout { get; set; }
-
-		/// <summary>
-		/// The <see cref="HttpRequestHeaders"/> used on every request.
-		/// </summary>
-		HttpRequestHeaders DefaultRequestHeaders { get; }
-
-		/// <summary>
-		/// Send an HTTP request.
-		/// </summary>
-		/// <param name="request">The <see cref="HttpRequestMessage"/>.</param>
-		/// <param name="completionOption">The <see cref="HttpCompletionOption"/>.</param>
-		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
-		/// <returns>A <see cref="Task{TResult}"/> resulting in the <see cref="HttpResponseMessage"/> of the request.</returns>
-		Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken);
-	}
-}

src/Tgstation.Server.Host/Components/Engine/OpenDreamInstallation.cs

@@ -12,7 +12,6 @@ using Microsoft.Extensions.Logging;
 
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Components.Deployment;
 using Tgstation.Server.Host.Components.Interop;
 using Tgstation.Server.Host.IO;
@@ -56,9 +55,9 @@ namespace Tgstation.Server.Host.Components.Engine
 		readonly IAsyncDelayer asyncDelayer;
 
 		/// <summary>
-		/// The <see cref="IAbstractHttpClientFactory"/> for the <see cref="OpenDreamInstallation"/>.
+		/// The <see cref="IHttpClientFactory"/> for the <see cref="OpenDreamInstallation"/>.
 		/// </summary>
-		readonly IAbstractHttpClientFactory httpClientFactory;
+		readonly IHttpClientFactory httpClientFactory;
 
 		/// <summary>
 		/// Path to the Robust.Server.dll.
@@ -84,7 +83,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		public OpenDreamInstallation(
 			IIOManager installationIOManager,
 			IAsyncDelayer asyncDelayer,
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			string dotnetPath,
 			string serverDllPath,
 			string compilerDllPath,

src/Tgstation.Server.Host/Components/Engine/OpenDreamInstaller.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -8,7 +9,6 @@ using Microsoft.Extensions.Options;
 
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Common.Extensions;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Components.Repository;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.IO;
@@ -77,9 +77,9 @@ namespace Tgstation.Server.Host.Components.Engine
 		readonly IAsyncDelayer asyncDelayer;
 
 		/// <summary>
-		/// The <see cref="IAbstractHttpClientFactory"/> for the <see cref="OpenDreamInstaller"/>.
+		/// The <see cref="IHttpClientFactory"/> for the <see cref="OpenDreamInstaller"/>.
 		/// </summary>
-		readonly IAbstractHttpClientFactory httpClientFactory;
+		readonly IHttpClientFactory httpClientFactory;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="OpenDreamInstaller"/> class.
@@ -100,7 +100,7 @@ namespace Tgstation.Server.Host.Components.Engine
 			IProcessExecutor processExecutor,
 			IRepositoryManager repositoryManager,
 			IAsyncDelayer asyncDelayer,
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			IOptions<GeneralConfiguration> generalConfigurationOptions,
 			IOptions<SessionConfiguration> sessionConfigurationOptions)
 			: base(ioManager, logger)

src/Tgstation.Server.Host/Components/Engine/WindowsOpenDreamInstaller.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -7,7 +8,6 @@ using Microsoft.Extensions.Options;
 
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Common.Extensions;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Components.Repository;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.IO;
@@ -36,7 +36,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="processExecutor">The <see cref="IProcessExecutor"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="repositoryManager">The <see cref="IRepositoryManager"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="asyncDelayer">The <see cref="IAsyncDelayer"/> for the <see cref="OpenDreamInstaller"/>.</param>
-		/// <param name="httpClientFactory">The <see cref="IAbstractHttpClientFactory"/> for the <see cref="OpenDreamInstaller"/>.</param>
+		/// <param name="httpClientFactory">The <see cref="IHttpClientFactory"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="generalConfigurationOptions">The <see cref="IOptions{TOptions}"/> of <see cref="GeneralConfiguration"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="sessionConfigurationOptions">The <see cref="IOptions{TOptions}"/> of <see cref="SessionConfiguration"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="linkFactory">The value of <see cref="linkFactory"/>.</param>
@@ -47,7 +47,7 @@ namespace Tgstation.Server.Host.Components.Engine
 			IProcessExecutor processExecutor,
 			IRepositoryManager repositoryManager,
 			IAsyncDelayer asyncDelayer,
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			IOptions<GeneralConfiguration> generalConfigurationOptions,
 			IOptions<SessionConfiguration> sessionConfigurationOptions,
 			IFilesystemLinkFactory linkFactory)

src/Tgstation.Server.Host/Core/Application.cs

@@ -46,7 +46,6 @@ using Serilog.Sinks.Elasticsearch;
 using Tgstation.Server.Api;
 using Tgstation.Server.Api.Hubs;
 using Tgstation.Server.Api.Models;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Authority;
 using Tgstation.Server.Host.Authority.Core;
 using Tgstation.Server.Host.Components;
@@ -311,8 +310,12 @@ namespace Tgstation.Server.Host.Core
 			services.AddCors();
 
 			// Enable managed HTTP clients
-			services.AddHttpClient();
-			services.AddSingleton<IAbstractHttpClientFactory, AbstractHttpClientFactory>();
+			services
+				.AddHttpClient()
+				.ConfigureHttpClientDefaults(
+					builder => builder.ConfigureHttpClient(
+						client => client.DefaultRequestHeaders.UserAgent.Add(
+							assemblyInformationProvider.ProductInfoHeaderValue)));
 
 			// configure metrics
 			var prometheusPort = postSetupServices.GeneralConfiguration.PrometheusPort;

src/Tgstation.Server.Host/IO/FileDownloader.cs

@@ -5,7 +5,6 @@ using System.Net.Http.Headers;
 using Microsoft.Extensions.Logging;
 
 using Tgstation.Server.Api;
-using Tgstation.Server.Common.Http;
 
 namespace Tgstation.Server.Host.IO
 {
@@ -13,9 +12,9 @@ namespace Tgstation.Server.Host.IO
 	public sealed class FileDownloader : IFileDownloader
 	{
 		/// <summary>
-		/// The <see cref="IAbstractHttpClientFactory"/> for the <see cref="FileDownloader"/>.
+		/// The <see cref="IHttpClientFactory"/> for the <see cref="FileDownloader"/>.
 		/// </summary>
-		readonly IAbstractHttpClientFactory httpClientFactory;
+		readonly IHttpClientFactory httpClientFactory;
 
 		/// <summary>
 		/// The <see cref="ILogger"/> for the <see cref="FileDownloader"/>.
@@ -27,7 +26,7 @@ namespace Tgstation.Server.Host.IO
 		/// </summary>
 		/// <param name="httpClientFactory">The value of <see cref="httpClientFactory"/>.</param>
 		/// <param name="logger">The value of <see cref="logger"/>.</param>
-		public FileDownloader(IAbstractHttpClientFactory httpClientFactory, ILogger<FileDownloader> logger)
+		public FileDownloader(IHttpClientFactory httpClientFactory, ILogger<FileDownloader> logger)
 		{
 			this.httpClientFactory = httpClientFactory ?? throw new ArgumentNullException(nameof(httpClientFactory));
 			this.logger = logger ?? throw new ArgumentNullException(nameof(logger));

src/Tgstation.Server.Host/IO/RequestFileStreamProvider.cs

@@ -14,9 +14,9 @@ namespace Tgstation.Server.Host.IO
 	sealed class RequestFileStreamProvider : IFileStreamProvider
 	{
 		/// <summary>
-		/// The <see cref="IHttpClient"/> for the <see cref="RequestFileStreamProvider"/>.
+		/// The <see cref="HttpClient"/> for the <see cref="RequestFileStreamProvider"/>.
 		/// </summary>
-		readonly IHttpClient httpClient;
+		readonly HttpClient httpClient;
 
 		/// <summary>
 		/// The <see cref="IFileDownloader"/> for the <see cref="RequestFileStreamProvider"/>.
@@ -43,7 +43,7 @@ namespace Tgstation.Server.Host.IO
 		/// </summary>
 		/// <param name="httpClient">The value of <see cref="httpClient"/>.</param>
 		/// <param name="requestMessage">The value of <see cref="requestMessage"/>.</param>
-		public RequestFileStreamProvider(IHttpClient httpClient, HttpRequestMessage requestMessage)
+		public RequestFileStreamProvider(HttpClient httpClient, HttpRequestMessage requestMessage)
 		{
 			this.httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));
 			this.requestMessage = requestMessage ?? throw new ArgumentNullException(nameof(requestMessage));

src/Tgstation.Server.Host/Security/OAuth/DiscordOAuthValidator.cs

@@ -1,9 +1,9 @@
 using System;
+using System.Net.Http;
 
 using Microsoft.Extensions.Logging;
 
 using Tgstation.Server.Api.Models;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Configuration;
 
 namespace Tgstation.Server.Host.Security.OAuth
@@ -25,11 +25,11 @@ namespace Tgstation.Server.Host.Security.OAuth
 		/// <summary>
 		/// Initializes a new instance of the <see cref="DiscordOAuthValidator"/> class.
 		/// </summary>
-		/// <param name="httpClientFactory">The <see cref="IAbstractHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.</param>
+		/// <param name="httpClientFactory">The <see cref="IHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		/// <param name="logger">The <see cref="ILogger"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		/// <param name="oAuthConfiguration">The <see cref="OAuthConfiguration"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		public DiscordOAuthValidator(
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			ILogger<DiscordOAuthValidator> logger,
 			OAuthConfiguration oAuthConfiguration)
 			: base(httpClientFactory, logger, oAuthConfiguration)

src/Tgstation.Server.Host/Security/OAuth/GenericOAuthValidator.cs

@@ -13,7 +13,6 @@ using Newtonsoft.Json.Serialization;
 
 using Tgstation.Server.Api;
 using Tgstation.Server.Api.Models;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.Extensions;
 
@@ -53,7 +52,7 @@ namespace Tgstation.Server.Host.Security.OAuth
 		/// <summary>
 		/// The <see cref="IHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.
 		/// </summary>
-		readonly IAbstractHttpClientFactory httpClientFactory;
+		readonly IHttpClientFactory httpClientFactory;
 
 		/// <summary>
 		/// Gets <see cref="JsonSerializerSettings"/> that should be used.
@@ -74,7 +73,7 @@ namespace Tgstation.Server.Host.Security.OAuth
 		/// <param name="logger">The value of <see cref="Logger"/>.</param>
 		/// <param name="oAuthConfiguration">The value of <see cref="OAuthConfiguration"/>.</param>
 		public GenericOAuthValidator(
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			ILogger<GenericOAuthValidator> logger,
 			OAuthConfiguration oAuthConfiguration)
 		{
@@ -178,10 +177,10 @@ namespace Tgstation.Server.Host.Security.OAuth
 		protected abstract OAuthTokenRequest CreateTokenRequest(string code);
 
 		/// <summary>
-		/// Create a new configured <see cref="IHttpClient"/>.
+		/// Create a new configured <see cref="HttpClient"/>.
 		/// </summary>
-		/// <returns>A new configured <see cref="IHttpClient"/>.</returns>
-		IHttpClient CreateHttpClient()
+		/// <returns>A new configured <see cref="HttpClient"/>.</returns>
+		HttpClient CreateHttpClient()
 		{
 			var httpClient = httpClientFactory.CreateClient();
 			try

src/Tgstation.Server.Host/Security/OAuth/InvisionCommunityOAuthValidator.cs

@@ -1,9 +1,9 @@
 using System;
+using System.Net.Http;
 
 using Microsoft.Extensions.Logging;
 
 using Tgstation.Server.Api.Models;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Configuration;
 
 namespace Tgstation.Server.Host.Security.OAuth
@@ -27,11 +27,11 @@ namespace Tgstation.Server.Host.Security.OAuth
 		/// <summary>
 		/// Initializes a new instance of the <see cref="InvisionCommunityOAuthValidator"/> class.
 		/// </summary>
-		/// <param name="httpClientFactory">The <see cref="IAbstractHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.</param>
+		/// <param name="httpClientFactory">The <see cref="IHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		/// <param name="logger">The <see cref="ILogger"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		/// <param name="oAuthConfiguration">The <see cref="OAuthConfiguration"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		public InvisionCommunityOAuthValidator(
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			ILogger<InvisionCommunityOAuthValidator> logger,
 			OAuthConfiguration oAuthConfiguration)
 			: base(httpClientFactory, logger, oAuthConfiguration)

src/Tgstation.Server.Host/Security/OAuth/KeycloakOAuthValidator.cs

@@ -1,9 +1,9 @@
 using System;
+using System.Net.Http;
 
 using Microsoft.Extensions.Logging;
 
 using Tgstation.Server.Api.Models;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Configuration;
 
 namespace Tgstation.Server.Host.Security.OAuth
@@ -32,11 +32,11 @@ namespace Tgstation.Server.Host.Security.OAuth
 		/// <summary>
 		/// Initializes a new instance of the <see cref="KeycloakOAuthValidator"/> class.
 		/// </summary>
-		/// <param name="httpClientFactory">The <see cref="IAbstractHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.</param>
+		/// <param name="httpClientFactory">The <see cref="IHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		/// <param name="logger">The <see cref="ILogger"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		/// <param name="oAuthConfiguration">The <see cref="OAuthConfiguration"/> for the <see cref="GenericOAuthValidator"/>.</param>
 		public KeycloakOAuthValidator(
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			ILogger<KeycloakOAuthValidator> logger,
 			OAuthConfiguration oAuthConfiguration)
 			: base(httpClientFactory, logger, oAuthConfiguration)

src/Tgstation.Server.Host/Security/OAuth/OAuthProviders.cs

@@ -1,12 +1,12 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net.Http;
 
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
 using Tgstation.Server.Api.Models;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.Utils.GitHub;
 
@@ -24,12 +24,12 @@ namespace Tgstation.Server.Host.Security.OAuth
 		/// Initializes a new instance of the <see cref="OAuthProviders"/> class.
 		/// </summary>
 		/// <param name="gitHubServiceFactory">The <see cref="IGitHubServiceFactory"/> to use.</param>
-		/// <param name="httpClientFactory">The <see cref="IAbstractHttpClientFactory"/> to use.</param>
+		/// <param name="httpClientFactory">The <see cref="IHttpClientFactory"/> to use.</param>
 		/// <param name="loggerFactory">The <see cref="ILoggerFactory"/> to use.</param>
 		/// <param name="securityConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing the <see cref="SecurityConfiguration"/> to use.</param>
 		public OAuthProviders(
 			IGitHubServiceFactory gitHubServiceFactory,
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			ILoggerFactory loggerFactory,
 			IOptions<SecurityConfiguration> securityConfigurationOptions)
 		{

src/Tgstation.Server.Host/Swarm/SwarmService.cs

@@ -19,7 +19,6 @@ using Newtonsoft.Json;
 using Tgstation.Server.Api.Models.Internal;
 using Tgstation.Server.Api.Models.Response;
 using Tgstation.Server.Common.Extensions;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.Core;
 using Tgstation.Server.Host.Database;
@@ -74,9 +73,9 @@ namespace Tgstation.Server.Host.Swarm
 		readonly IAssemblyInformationProvider assemblyInformationProvider;
 
 		/// <summary>
-		/// The <see cref="IAbstractHttpClientFactory"/> for the <see cref="SwarmService"/>.
+		/// The <see cref="IHttpClientFactory"/> for the <see cref="SwarmService"/>.
 		/// </summary>
-		readonly IAbstractHttpClientFactory httpClientFactory;
+		readonly IHttpClientFactory httpClientFactory;
 
 		/// <summary>
 		/// The <see cref="IAsyncDelayer"/> for the <see cref="SwarmService"/>.
@@ -175,7 +174,7 @@ namespace Tgstation.Server.Host.Swarm
 			IDatabaseContextFactory databaseContextFactory,
 			IDatabaseSeeder databaseSeeder,
 			IAssemblyInformationProvider assemblyInformationProvider,
-			IAbstractHttpClientFactory httpClientFactory,
+			IHttpClientFactory httpClientFactory,
 			IAsyncDelayer asyncDelayer,
 			IServerUpdater serverUpdater,
 			IFileTransferTicketProvider transferService,

src/Tgstation.Server.Host/Utils/AbstractHttpClientFactory.cs

@@ -1,76 +0,0 @@
-using System;
-using System.Net.Http;
-
-using Microsoft.Extensions.Logging;
-
-using Tgstation.Server.Common.Http;
-using Tgstation.Server.Host.System;
-
-namespace Tgstation.Server.Host.Utils
-{
-	/// <inheritdoc />
-	sealed class AbstractHttpClientFactory : IAbstractHttpClientFactory
-	{
-		/// <summary>
-		/// The real <see cref="IHttpClientFactory"/>.
-		/// </summary>
-		readonly IHttpClientFactory httpClientFactory;
-
-		/// <summary>
-		/// The <see cref="IAssemblyInformationProvider"/> for the <see cref="AbstractHttpClientFactory"/>.
-		/// </summary>
-		readonly IAssemblyInformationProvider assemblyInformationProvider;
-
-		/// <summary>
-		/// The <see cref="ILogger"/> for the <see cref="AbstractHttpClientFactory"/>.
-		/// </summary>
-		readonly ILogger<AbstractHttpClientFactory> logger;
-
-		/// <summary>
-		/// Initializes a new instance of the <see cref="AbstractHttpClientFactory"/> class.
-		/// </summary>
-		/// <param name="httpClientFactory">The value of <see cref="httpClientFactory"/>.</param>
-		/// <param name="assemblyInformationProvider">The value of <see cref="assemblyInformationProvider"/>.</param>
-		/// <param name="logger">The value of <see cref="logger"/>.</param>
-		public AbstractHttpClientFactory(
-			IHttpClientFactory httpClientFactory,
-			IAssemblyInformationProvider assemblyInformationProvider,
-			ILogger<AbstractHttpClientFactory> logger)
-		{
-			this.httpClientFactory = httpClientFactory ?? throw new ArgumentNullException(nameof(httpClientFactory));
-			this.assemblyInformationProvider = assemblyInformationProvider ?? throw new ArgumentNullException(nameof(assemblyInformationProvider));
-			this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
-		}
-
-		/// <inheritdoc />
-#pragma warning disable IDE0079
-#pragma warning disable CA2000
-		public IHttpClient CreateClient()
-		{
-			logger.LogTrace("Creating client...");
-			var innerClient = httpClientFactory.CreateClient();
-			try
-			{
-				var client = new Tgstation.Server.Common.Http.HttpClient(innerClient);
-				innerClient = null;
-				try
-				{
-					client.DefaultRequestHeaders.UserAgent.Add(assemblyInformationProvider.ProductInfoHeaderValue);
-					return client;
-				}
-				catch
-				{
-					client.Dispose();
-					throw;
-				}
-			}
-			catch
-			{
-				innerClient?.Dispose();
-				throw;
-			}
-		}
-#pragma warning restore CA2000
-#pragma warning restore IDE0079
-	}
-}

tests/Tgstation.Server.Client.Tests/TestApiClient.cs

@@ -15,6 +15,7 @@ using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
 using Tgstation.Server.Api.Models.Response;
 using Tgstation.Server.Common.Http;
+using Tgstation.Server.Common.Tests;
 
 namespace Tgstation.Server.Client.Tests
 {
@@ -44,11 +45,10 @@ namespace Tgstation.Server.Client.Tests
 				Content = new StringContent(sampleJson)
 			};
 
-			var httpClient = new Mock<IHttpClient>();
-			httpClient.Setup(x => x.SendAsync(It.IsNotNull<HttpRequestMessage>(), It.IsAny<HttpCompletionOption>(), It.IsAny<CancellationToken>())).Returns(Task.FromResult(response));
+			var handler = new MockHttpMessageHandler((_, __) => Task.FromResult(response));
 
 			var client = new ApiClient(
-				httpClient.Object,
+				new HttpClient(handler),
 				new Uri("http://fake.com"),
 				new ApiHeaders(
 					new ProductHeaderValue("fake"),
@@ -84,11 +84,10 @@ namespace Tgstation.Server.Client.Tests
 				Content = new StringContent(fakeJson)
 			};
 
-			var httpClient = new Mock<IHttpClient>();
-			httpClient.Setup(x => x.SendAsync(It.IsNotNull<HttpRequestMessage>(), It.IsAny<HttpCompletionOption>(), It.IsAny<CancellationToken>())).Returns(Task.FromResult(response));
+			var handler = new MockHttpMessageHandler((_, __) => Task.FromResult(response));
 
 			var client = new ApiClient(
-				httpClient.Object,
+				new HttpClient(handler),
 				new Uri("http://fake.com"),
 				new ApiHeaders(
 					new ProductHeaderValue("fake"),

tests/Tgstation.Server.Client.Tests/Tgstation.Server.Client.Tests.csproj

@@ -11,6 +11,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Tgstation.Server.Client\Tgstation.Server.Client.csproj" />
+    <ProjectReference Include="..\Tgstation.Server.Common.Tests\Tgstation.Server.Common.Tests.csproj" />
   </ItemGroup>
 
 </Project>

tests/Tgstation.Server.Common.Tests/Extensions/TestVersionExtensions.cs

@@ -0,0 +1,19 @@
+using System;
+
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Tgstation.Server.Common.Extensions.Tests
+{
+	/// <summary>
+	/// Tests for <see cref="VersionExtensions"/>.
+	/// </summary>
+	[TestClass]
+	public sealed class TestVersionExtensions
+	{
+		[TestMethod]
+		public void TestSemver()
+		{
+			Assert.AreEqual(new Version(1, 2, 3), new Version(1, 2, 3, 4).Semver());
+		}
+	}
+}

tests/Tgstation.Server.Common.Tests/MockHttpMessageHandler.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Tgstation.Server.Common.Tests
+{
+	/// <summary>
+	/// Simple mock <see cref="HttpMessageHandler"/>.
+	/// </summary>
+	public sealed class MockHttpMessageHandler : HttpMessageHandler
+	{
+		readonly Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> callback;
+
+		public MockHttpMessageHandler(Func<HttpRequestMessage, CancellationToken, Task<HttpResponseMessage>> callback)
+		{
+			this.callback = callback ?? throw new ArgumentNullException(nameof(callback));
+		}
+
+		protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+			=> callback(request, cancellationToken);
+	}
+}

tests/Tgstation.Server.Common.Tests/Tgstation.Server.Common.Tests.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <Import Project="../../build/TestCommon.props" />
+
+  <PropertyGroup>
+    <TargetFramework>$(TgsFrameworkVersion)</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Tgstation.Server.Common\Tgstation.Server.Common.csproj" />
+  </ItemGroup>
+
+</Project>

tests/Tgstation.Server.Host.Tests/Components/Engine/TestOpenDreamInstaller.cs

@@ -1,4 +1,5 @@
-using System.Threading;
+using System.Net.Http;
+using System.Threading;
 using System.Threading.Tasks;
 
 using Microsoft.Extensions.Logging;
@@ -8,8 +9,6 @@ using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Moq;
 
 using Tgstation.Server.Api.Models;
-using Tgstation.Server.Api.Models.Internal;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Components.Repository;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.IO;
@@ -76,7 +75,7 @@ namespace Tgstation.Server.Host.Components.Engine.Tests
 				Mock.Of<IProcessExecutor>(),
 				mockRepositoryManager.Object,
 				Mock.Of<IAsyncDelayer>(),
-				Mock.Of<IAbstractHttpClientFactory>(),
+				Mock.Of<IHttpClientFactory>(),
 				mockGeneralConfigOptions.Object,
 				mockSessionConfigOptions.Object);
 

tests/Tgstation.Server.Host.Tests/IO/TestFileDownloader.cs

@@ -1,5 +1,7 @@
 using System;
 using System.IO;
+using System.Net;
+using System.Net.Http;
 using System.Text;
 using System.Threading.Tasks;
 
@@ -8,7 +10,7 @@ using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 using Moq;
 
-using Tgstation.Server.Common.Http;
+using Tgstation.Server.Common.Tests;
 using Tgstation.Server.Host.System;
 
 namespace Tgstation.Server.Host.IO.Tests
@@ -27,8 +29,8 @@ Please see the following for more context:
 		public void TestConstructor()
 		{
 			Assert.ThrowsException<ArgumentNullException>(() => new FileDownloader(null, null));
-			Assert.ThrowsException<ArgumentNullException>(() => new FileDownloader(Mock.Of<IAbstractHttpClientFactory>(), null));
-			_ = new FileDownloader(Mock.Of<IAbstractHttpClientFactory>(), Mock.Of<ILogger<FileDownloader>>());
+			Assert.ThrowsException<ArgumentNullException>(() => new FileDownloader(Mock.Of<IHttpClientFactory>(), null));
+			_ = new FileDownloader(Mock.Of<IHttpClientFactory>(), Mock.Of<ILogger<FileDownloader>>());
 		}
 
 		[TestMethod]
@@ -65,11 +67,21 @@ Please see the following for more context:
 				builder.SetMinimumLevel(LogLevel.Trace);
 			});
 
+			var mockHttpClientFactory = new Mock<IHttpClientFactory>();
+			var httpClient = new HttpClient(
+				new MockHttpMessageHandler(
+					(_, __) => Task.FromResult(
+						new HttpResponseMessage(HttpStatusCode.OK)
+						{
+							Content = new StringContent(ExpectedData),
+						})));
+
+			mockHttpClientFactory.Setup(x => x.CreateClient(String.Empty)).Returns(httpClient);
+
 			try
 			{
 				return new FileDownloader(
-					new HttpClientFactory(
-						new AssemblyInformationProvider().ProductInfoHeaderValue),
+					mockHttpClientFactory.Object,
 					loggerFactory.CreateLogger<FileDownloader>());
 			}
 			catch

tests/Tgstation.Server.Host.Tests/IO/TestRequestFileStreamProvider.cs

@@ -10,6 +10,7 @@ using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Moq;
 
 using Tgstation.Server.Common.Http;
+using Tgstation.Server.Common.Tests;
 using Tgstation.Server.Host.Extensions;
 
 namespace Tgstation.Server.Host.IO.Tests
@@ -21,7 +22,7 @@ namespace Tgstation.Server.Host.IO.Tests
 		public async Task TestConstruction()
 		{
 			Assert.ThrowsException<ArgumentNullException>(() => new RequestFileStreamProvider(null, null));
-			var mockClient = Mock.Of<IHttpClient>();
+			var mockClient = new HttpClient();
 			Assert.ThrowsException<ArgumentNullException>(() => new RequestFileStreamProvider(mockClient, null));
 			await using var test = new RequestFileStreamProvider(mockClient, new HttpRequestMessage());
 		}
@@ -31,21 +32,23 @@ namespace Tgstation.Server.Host.IO.Tests
 		{
 			var sequence = new byte[] { 1, 2, 3 };
 			var resultMs = new MemoryStream(sequence);
-			var mockHttpClient = new Mock<IHttpClient>();
 
 			var response = new HttpResponseMessage()
 			{
 				Content = new StreamContent(resultMs),
 			};
 
-
+			var ran = false;
 			var request = new HttpRequestMessage();
-			mockHttpClient
-				.Setup(x => x.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, It.IsAny<CancellationToken>()))
-				.Returns(Task.FromResult(response))
-				.Verifiable();
+			var mockHttpClient = new HttpClient(
+				new MockHttpMessageHandler(
+					(_, _) =>
+					{
+						ran = true;
+						return Task.FromResult(response);
+					}));
 
-			await using var downloader = new RequestFileStreamProvider(mockHttpClient.Object, request);
+			await using var downloader = new RequestFileStreamProvider(mockHttpClient, request);
 
 			var download = await downloader.GetResult(default);
 
@@ -55,8 +58,7 @@ namespace Tgstation.Server.Host.IO.Tests
 
 			var resultSequence = buffer.ToArray();
 			Assert.IsTrue(sequence.SequenceEqual(resultSequence));
-
-			mockHttpClient.VerifyAll();
+			Assert.IsTrue(ran);
 		}
 
 		[TestMethod]
@@ -64,20 +66,23 @@ namespace Tgstation.Server.Host.IO.Tests
 		{
 			var sequence = new byte[] { 1, 2, 3 };
 			var resultMs = new MemoryStream(sequence);
-			var mockHttpClient = new Mock<IHttpClient>();
 
 			var response = new HttpResponseMessage()
 			{
 				Content = new StreamContent(resultMs),
 			};
 
+			int ran = 0;
 			var request = new HttpRequestMessage();
-			mockHttpClient
-				.Setup(x => x.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, It.IsAny<CancellationToken>()))
-				.Returns(Task.FromResult(response))
-				.Verifiable();
+			var mockHttpClient = new HttpClient(
+				new MockHttpMessageHandler(
+					(_, _) =>
+					{
+						++ran;
+						return Task.FromResult(response);
+					}));
 
-			await using var downloader = new RequestFileStreamProvider(mockHttpClient.Object, request);
+			await using var downloader = new RequestFileStreamProvider(mockHttpClient, request);
 
 			var task1 = downloader.GetResult(default);
 			var task2 = downloader.GetResult(default);
@@ -93,15 +98,13 @@ namespace Tgstation.Server.Host.IO.Tests
 			Assert.AreSame(task1Result, await task2);
 			Assert.AreSame(task1Result, await task3);
 
-			mockHttpClient.VerifyAll();
-			Assert.AreEqual(1, mockHttpClient.Invocations.Count);
+			Assert.AreEqual(1, ran);
 		}
 
 		[TestMethod]
 		public async Task TestInterruptedDownload()
 		{
 			var resultMs = new MemoryStream();
-			var mockHttpClient = new Mock<IHttpClient>();
 
 			var response = new HttpResponseMessage()
 			{
@@ -110,17 +113,17 @@ namespace Tgstation.Server.Host.IO.Tests
 
 			var tcs = new TaskCompletionSource<HttpResponseMessage>();
 
+			var ran = false;
 			var request = new HttpRequestMessage();
-			mockHttpClient
-				.Setup(x => x.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, It.IsAny<CancellationToken>()))
-				.Returns<HttpRequestMessage, HttpCompletionOption, CancellationToken>((request, option, cancellationToken) =>
-				{
-					cancellationToken.Register(() => tcs.TrySetCanceled(cancellationToken));
-					return tcs.Task;
-				})
-				.Verifiable();
+			var mockHttpClient = new HttpClient(
+				new MockHttpMessageHandler(
+					(_, _) =>
+					{
+						ran = true;
+						return Task.FromResult(response);
+					}));
 
-			await using var downloader = new RequestFileStreamProvider(mockHttpClient.Object, request);
+			await using var downloader = new RequestFileStreamProvider(mockHttpClient, request);
 
 			using var cts1 = new CancellationTokenSource();
 			var task1 = downloader.GetResult(cts1.Token);
@@ -133,11 +136,11 @@ namespace Tgstation.Server.Host.IO.Tests
 
 			cts2.Cancel();
 
-			await Assert.ThrowsExceptionAsync<TaskCanceledException>(() => task1.AsTask());
-			await Assert.ThrowsExceptionAsync<TaskCanceledException>(() => task2.AsTask());
-			await Assert.ThrowsExceptionAsync<TaskCanceledException>(() => task3.AsTask());
+			await Assert.ThrowsExceptionAsync<TaskCanceledException>(task1.AsTask);
+			await Assert.ThrowsExceptionAsync<TaskCanceledException>(task2.AsTask);
+			await Assert.ThrowsExceptionAsync<TaskCanceledException>(task3.AsTask);
 
-			mockHttpClient.VerifyAll();
+			Assert.IsTrue(ran);
 		}
 	}
 }

tests/Tgstation.Server.Host.Tests/Swarm/SwarmRpcMapper.cs

@@ -21,7 +21,7 @@ using Moq;
 
 using Newtonsoft.Json;
 
-using Tgstation.Server.Common.Http;
+using Tgstation.Server.Common.Tests;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.Controllers;
 using Tgstation.Server.Host.Controllers.Results;
@@ -41,12 +41,10 @@ namespace Tgstation.Server.Host.Swarm.Tests
 
 		int serverErrorCount;
 
-		public SwarmRpcMapper(Func<SwarmService, FileTransferService, SwarmController> createSwarmController, Mock<IHttpClient> clientMock, ILogger logger)
+		public SwarmRpcMapper(Func<SwarmService, FileTransferService, SwarmController> createSwarmController, ILogger logger, out HttpMessageHandler handlerMock)
 		{
 			this.createSwarmController = createSwarmController;
-			clientMock
-				.Setup(x => x.SendAsync(It.IsNotNull<HttpRequestMessage>(), It.IsAny<HttpCompletionOption>(), It.IsAny<CancellationToken>()))
-				.Returns(MapRequest);
+			handlerMock = new MockHttpMessageHandler(MapRequest);
 			this.logger = logger;
 			AsyncRequests = true;
 		}
@@ -63,7 +61,6 @@ namespace Tgstation.Server.Host.Swarm.Tests
 
 		async Task<HttpResponseMessage> MapRequest(
 			HttpRequestMessage request,
-			HttpCompletionOption httpCompletionOption,
 			CancellationToken cancellationToken)
 		{
 			var (config, transferService, node) = configToNodes.FirstOrDefault(

tests/Tgstation.Server.Host.Tests/Swarm/TestableSwarmNode.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net.Http;
 using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
@@ -50,7 +51,6 @@ namespace Tgstation.Server.Host.Swarm.Tests
 
 		public bool Shutdown { get; private set; }
 
-		readonly Mock<IHttpClient> mockHttpClient;
 		readonly Mock<IDatabaseContextFactory> mockDBContextFactory;
 		readonly Mock<IDatabaseSeeder> mockDatabaseSeeder;
 		readonly ISetup<IDatabaseSeeder, ValueTask> mockDatabaseSeederInitialize;
@@ -121,10 +121,6 @@ namespace Tgstation.Server.Host.Swarm.Tests
 				.Setup(x => x.UseContextTaskReturn(It.IsNotNull<Func<IDatabaseContext, Task>>()))
 				.Callback<Func<IDatabaseContext, Task>>((func) => func(mockDatabaseContext));
 
-			var mockHttpClientFactory = new Mock<IAbstractHttpClientFactory>();
-			mockHttpClient = new Mock<IHttpClient>();
-			mockHttpClientFactory.Setup(x => x.CreateClient()).Returns(mockHttpClient.Object);
-
 			var mockAsyncDelayer = new Mock<IAsyncDelayer>();
 			mockAsyncDelayer.Setup(
 				x => x.Delay(It.IsAny<TimeSpan>(), It.IsAny<CancellationToken>()))
@@ -161,8 +157,8 @@ namespace Tgstation.Server.Host.Swarm.Tests
 					targetTransfer,
 					mockOptions.Object,
 					loggerFactory.CreateLogger<SwarmController>()),
-				mockHttpClient,
-				loggerFactory.CreateLogger($"SwarmRpcMapper-{swarmConfiguration.Identifier}"));
+				loggerFactory.CreateLogger($"SwarmRpcMapper-{swarmConfiguration.Identifier}"),
+				out var mockMessageHandler);
 
 			mockServerUpdater
 				.Setup(x => x.BeginUpdate(It.IsNotNull<ISwarmService>(), It.IsAny<IFileStreamProvider>(), It.IsNotNull<Version>(), It.IsAny<CancellationToken>()))
@@ -175,6 +171,9 @@ namespace Tgstation.Server.Host.Swarm.Tests
 
 			var mockTokenFactory = new MockTokenFactory();
 
+			var mockHttpClientFactory = new Mock<IHttpClientFactory>();
+			mockHttpClientFactory.Setup(x => x.CreateClient(String.Empty)).Returns(() => new HttpClient(mockMessageHandler));
+
 			var runCount = 0;
 			void RecreateControllerAndService()
 			{

tests/Tgstation.Server.Host.Tests/Tgstation.Server.Host.Tests.csproj

@@ -14,6 +14,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Tgstation.Server.Host\Tgstation.Server.Host.csproj" />
+    <ProjectReference Include="..\Tgstation.Server.Common.Tests\Tgstation.Server.Common.Tests.csproj" />
   </ItemGroup>
 
 </Project>

tests/Tgstation.Server.Tests/CachingFileDownloader.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.IO.Abstractions;
+using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -174,16 +175,26 @@ namespace Tgstation.Server.Tests
 
 		public IFileStreamProvider DownloadFile(Uri url, string bearerToken) => new ProviderPackage(logger, url, bearerToken);
 
-		static FileDownloader CreateRealDownloader(ILogger logger)
-			=> new(
-				new HttpClientFactory(
-					new AssemblyInformationProvider().ProductInfoHeaderValue),
+		public static FileDownloader CreateRealDownloader(ILogger logger)
+		{
+			var mockHttpClientFactory = new Mock<IHttpClientFactory>();
+			mockHttpClientFactory.Setup(x => x.CreateClient(String.Empty)).Returns(
+				() =>
+				{
+					var client = new HttpClient();
+					client.DefaultRequestHeaders.UserAgent.Add(new AssemblyInformationProvider().ProductInfoHeaderValue);
+					return client;
+				});
+
+			return new (
+				mockHttpClientFactory.Object,
 				logger != null
 					? new Logger<FileDownloader>(
 						TestingUtils.CreateLoggerFactoryForLogger(
 							logger,
 							out _))
 					: Mock.Of<ILogger<FileDownloader>>());
+		}
 
 		static async Task<MemoryStream> CacheFile(ILogger logger, Uri url, string bearerToken, string path, CancellationToken cancellationToken)
 		{

tests/Tgstation.Server.Tests/Live/Instance/InstanceTest.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO.Abstractions;
 using System.Linq;
+using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -16,7 +17,6 @@ using Tgstation.Server.Api.Models.Request;
 using Tgstation.Server.Api.Models.Response;
 using Tgstation.Server.Client;
 using Tgstation.Server.Client.Components;
-using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Components;
 using Tgstation.Server.Host.Components.Engine;
 using Tgstation.Server.Host.Components.Events;
@@ -126,7 +126,7 @@ namespace Tgstation.Server.Tests.Live.Instance
 						Mock.Of<ILogger<RepositoryManager>>(),
 						genConfig),
 					Mock.Of<IAsyncDelayer>(),
-					Mock.Of<IAbstractHttpClientFactory>(),
+					Mock.Of<IHttpClientFactory>(),
 					Options.Create(genConfig),
 					Options.Create(new SessionConfiguration()))
 				: new PlatformIdentifier().IsWindows

tests/Tgstation.Server.Tests/Live/RateLimitRetryingApiClient.cs

@@ -14,7 +14,7 @@ namespace Tgstation.Server.Tests.Live
 	sealed class RateLimitRetryingApiClient : ApiClient
 	{
 		public RateLimitRetryingApiClient(
-			IHttpClient httpClient,
+			HttpClient httpClient,
 			Uri url,
 			ApiHeaders apiHeaders,
 			ApiHeaders tokenRefreshHeaders,

tests/Tgstation.Server.Tests/Live/RateLimitRetryingApiClientFactory.cs

@@ -1,9 +1,8 @@
 using System;
+using System.Net.Http;
 
 using Tgstation.Server.Api;
-using Tgstation.Server.Api.Models.Response;
 using Tgstation.Server.Client;
-using Tgstation.Server.Common.Http;
 
 namespace Tgstation.Server.Tests.Live
 {
@@ -20,5 +19,19 @@ namespace Tgstation.Server.Tests.Live
 				apiHeaders,
 				tokenRefreshHeaders,
 				authless);
+
+		/// <inheritdoc />
+		public IApiClient CreateApiClient(
+			Uri url,
+			ApiHeaders apiHeaders,
+			ApiHeaders tokenRefreshHeaders,
+			HttpMessageHandler handler,
+			bool disposeHandler,
+			bool authless) => new RateLimitRetryingApiClient(
+				new HttpClient(handler, disposeHandler),
+				url,
+				apiHeaders,
+				tokenRefreshHeaders,
+				authless);
 	}
 }

tests/Tgstation.Server.Tests/Live/TestLiveServer.cs

@@ -409,10 +409,7 @@ namespace Tgstation.Server.Tests.Live
 				await CheckUpdate();
 
 				// Second pass, uploaded updates
-				var downloader = new Host.IO.FileDownloader(
-					new Common.Http.HttpClientFactory(
-						new AssemblyInformationProvider().ProductInfoHeaderValue),
-					Mock.Of<ILogger<Host.IO.FileDownloader>>());
+				var downloader = CachingFileDownloader.CreateRealDownloader(Mock.Of<ILogger<Host.IO.FileDownloader>>());
 				var gitHubToken = Environment.GetEnvironmentVariable("TGS_TEST_GITHUB_TOKEN");
 				if (String.IsNullOrWhiteSpace(gitHubToken))
 					gitHubToken = null;
@@ -828,10 +825,7 @@ namespace Tgstation.Server.Tests.Live
 					CheckInfo(node2Info2);
 
 					// also test with uploaded updates this time
-					var downloader = new Host.IO.FileDownloader(
-						new Common.Http.HttpClientFactory(
-							new AssemblyInformationProvider().ProductInfoHeaderValue),
-						Mock.Of<ILogger<Host.IO.FileDownloader>>());
+					var downloader = CachingFileDownloader.CreateRealDownloader(Mock.Of<ILogger<Host.IO.FileDownloader>>());
 					var gitHubToken = Environment.GetEnvironmentVariable("TGS_TEST_GITHUB_TOKEN");
 					if (String.IsNullOrWhiteSpace(gitHubToken))
 						gitHubToken = null;

tgstation-server.sln

@@ -277,6 +277,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "nix", "nix", "{5130526C-A55
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Tgstation.Server.Host.Utils.GitLab.GraphQL", "src\Tgstation.Server.Host.Utils.GitLab.GraphQL\Tgstation.Server.Host.Utils.GitLab.GraphQL.csproj", "{BF02BCC5-735C-4FF1-8EEF-FF78EA42FC85}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Tgstation.Server.Common.Tests", "tests\Tgstation.Server.Common.Tests\Tgstation.Server.Common.Tests.csproj", "{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -571,6 +573,18 @@ Global
 		{BF02BCC5-735C-4FF1-8EEF-FF78EA42FC85}.ReleaseNoWindows|Any CPU.Build.0 = Release|Any CPU
 		{BF02BCC5-735C-4FF1-8EEF-FF78EA42FC85}.ReleaseNoWix|Any CPU.ActiveCfg = Release|Any CPU
 		{BF02BCC5-735C-4FF1-8EEF-FF78EA42FC85}.ReleaseNoWix|Any CPU.Build.0 = Release|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.DebugNoWindows|Any CPU.ActiveCfg = Debug|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.DebugNoWindows|Any CPU.Build.0 = Debug|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.DebugNoWix|Any CPU.ActiveCfg = Debug|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.DebugNoWix|Any CPU.Build.0 = Debug|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.Release|Any CPU.Build.0 = Release|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.ReleaseNoWindows|Any CPU.ActiveCfg = Release|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.ReleaseNoWindows|Any CPU.Build.0 = Release|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.ReleaseNoWix|Any CPU.ActiveCfg = Release|Any CPU
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084}.ReleaseNoWix|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -609,6 +623,7 @@ Global
 		{7F7FCFDF-271D-45C2-830C-BCCB19C57077} = {A55C1117-5808-4AB2-BEA6-4D4A3E66A2F2}
 		{EAB84FD0-5514-4254-B188-7D90ACB7284D} = {316141B0-CD21-4769-A013-D53DA9B9EC09}
 		{5130526C-A553-493B-A9B0-3DB452949886} = {2648A85F-61AE-428E-95E1-66D06C7A3768}
+		{73F2C6B9-54A6-4433-9D94-07F2AC0FD084} = {316141B0-CD21-4769-A013-D53DA9B9EC09}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {DFD36C95-3E49-41C7-ACDB-86BAF5B18A79}