Handle database conflicts at a higher level with middleware

src/Tgstation.Server.Host/Controllers/InstanceController.cs

@@ -211,14 +211,7 @@ namespace Tgstation.Server.Host.Controllers
 
 			var attachFileName = ioManager.ConcatPath(originalModel.Path, InstanceAttachFileName);
 			await ioManager.WriteAllBytes(attachFileName, Array.Empty<byte>(), default).ConfigureAwait(false);
-			try
-			{
-				await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);    //cascades everything
-			}
-			catch (DbUpdateException e)
-			{
-				return Conflict(new ErrorMessage { Message = e.Message });
-			}
+			await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);   //cascades everything
 			return Ok();
 		}
 

src/Tgstation.Server.Host/Controllers/InstanceUserController.cs

@@ -69,14 +69,7 @@ namespace Tgstation.Server.Host.Controllers
 
 			DatabaseContext.InstanceUsers.Add(dbUser);
 
-			try
-			{
-				await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);
-			}
-			catch (DbUpdateConcurrencyException e)
-			{
-				return Conflict(new ErrorMessage { Message = e.Message });
-			}
+			await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);
 			return Json(dbUser.ToApi());
 		}
 
@@ -98,14 +91,7 @@ namespace Tgstation.Server.Host.Controllers
 			originalUser.DreamDaemonRights = model.DreamDaemonRights ?? originalUser.DreamDaemonRights;
 			originalUser.DreamMakerRights = model.DreamMakerRights ?? originalUser.DreamMakerRights;
 
-			try
-			{
-				await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);
-			}
-			catch (DbUpdateConcurrencyException e)
-			{
-				return Conflict(new ErrorMessage { Message = e.Message });
-			}
+			await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);
 			return Json(originalUser.ToApi());
 		}
 

src/Tgstation.Server.Host/Controllers/UserController.cs

@@ -116,22 +116,7 @@ namespace Tgstation.Server.Host.Controllers
 
 			DatabaseContext.Users.Add(dbUser);
 
-			try
-			{
-				try
-				{
-					await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);
-				}
-				catch (Exception e)
-				{
-					logger.LogInformation("Error creating user: {0}", e);
-					throw;
-				}
-			}
-			catch (DbUpdateConcurrencyException e)
-			{
-				return Conflict(new { message = e.Message });
-			}
+			await DatabaseContext.Save(cancellationToken).ConfigureAwait(false);
 
 			return Json(dbUser.ToApi());
 		}

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

@@ -22,7 +22,6 @@ using Tgstation.Server.Host.Components;
 using Tgstation.Server.Host.Components.Byond;
 using Tgstation.Server.Host.Components.Chat;
 using Tgstation.Server.Host.Components.StaticFiles;
-using Tgstation.Server.Host.Components.Watchdog;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.Controllers;
 using Tgstation.Server.Host.IO;
@@ -249,6 +248,9 @@ namespace Tgstation.Server.Host.Core
 			});
 
 			applicationBuilder.UseAuthentication();
+
+			applicationBuilder.UseDbConflictHandling();
+
 			applicationBuilder.UseMvc();
 		}
 

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

@@ -0,0 +1,36 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Globalization;
+using Tgstation.Server.Api.Models;
+
+namespace Tgstation.Server.Host.Core
+{
+	/// <summary>
+	/// Extensions for <see cref="IApplicationBuilder"/>
+	/// </summary>
+	static class ApplicationBuilderExtensions
+	{
+		/// <summary>
+		/// Return a <see cref="ConflictObjectResult"/> for <see cref="DbUpdateException"/>s
+		/// </summary>
+		/// <param name="applicationBuilder">The <see cref="IApplicationBuilder"/> to configure</param>
+		public static void UseDbConflictHandling(this IApplicationBuilder applicationBuilder) => applicationBuilder.Use(async (context, next) =>
+		{
+			if (applicationBuilder == null)
+				throw new ArgumentNullException(nameof(applicationBuilder));
+			try
+			{
+				await next().ConfigureAwait(false);
+			}
+			catch (DbUpdateException e)
+			{
+				await new ConflictObjectResult(new ErrorMessage { Message = String.Format(CultureInfo.InvariantCulture, "A database conflict has occurred: {0}", (e.InnerException ?? e).Message) }).ExecuteResultAsync(new ActionContext
+				{
+					HttpContext = context
+				}).ConfigureAwait(false);
+			}
+		});
+	}
+}

src/Tgstation.Server.Host/Models/DatabaseContext.cs

@@ -141,7 +141,7 @@ namespace Tgstation.Server.Host.Models
 			Logger.LogInformation("Migrating database...");
 
 			var wasEmpty = false;
-			if (!databaseConfiguration.NoMigrations)
+			if (databaseConfiguration.NoMigrations)
 			{
 				Logger.LogWarning("Using all or nothing migration strategy!");
 				await Database.EnsureCreatedAsync(cancellationToken).ConfigureAwait(false);

src/Tgstation.Server.Host/Properties/launchSettings.json

@@ -1,27 +1,12 @@
 {
-  "iisSettings": {
-    "windowsAuthentication": false,
-    "anonymousAuthentication": true,
-    "iisExpress": {
-      "applicationUrl": "http://localhost:52906/",
-      "sslPort": 0
-    }
-  },
   "profiles": {
-    "IIS Express": {
-      "commandName": "IISExpress",
-      "launchBrowser": true,
-      "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
-      }
-    },
     "Tgstation.Server.Host": {
       "commandName": "Project",
-      "launchBrowser": true,
+      "launchBrowser": false,
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
       },
-      "applicationUrl": "http://localhost:52907/"
+      "applicationUrl": "http://localhost:5000/"
     }
   }
 }

tools/TGS.postman_collection.json

@@ -266,6 +266,45 @@
 					},
 					"response": []
 				},
+				{
+					"name": "Create User admin",
+					"request": {
+						"method": "PUT",
+						"header": [
+							{
+								"key": "Accept",
+								"value": "application/json"
+							},
+							{
+								"key": "User-Agent",
+								"value": "Postman/1.0"
+							},
+							{
+								"key": "Api",
+								"value": "Tgstation.Server.Api/4.0.0.0"
+							},
+							{
+								"key": "Content-Type",
+								"value": "application/json"
+							}
+						],
+						"body": {
+							"mode": "raw",
+							"raw": "{\n    \"password\": \"asdfasdfasdfasdfasdf\",\n    \"name\": \"admin\"\n}"
+						},
+						"url": {
+							"raw": "localhost:5000/User",
+							"host": [
+								"localhost"
+							],
+							"port": "5000",
+							"path": [
+								"User"
+							]
+						}
+					},
+					"response": []
+				},
 				{
 					"name": "Try To Add A SysId To User ID 2",
 					"request": {
@@ -544,7 +583,7 @@
 						],
 						"body": {
 							"mode": "raw",
-							"raw": "{\n    \"systemIdentifier\": \"Cyberboss\"\n}"
+							"raw": "{\n    \"systemIdentifier\": \"TESSONICS\\\\Jordan\"\n}"
 						},
 						"url": {
 							"raw": "localhost:5000/User",