From b492595ec28016e88ceee6385a57a0686b77d33e Mon Sep 17 00:00:00 2001
From: Andrew Lock <andrewlock.net@gmail.com>
Date: Thu, 15 Jun 2023 20:59:13 +0100
Subject: [PATCH] ioptions-validation-minivalidation

---
 .../IOptionsValidationMiniValidation.csproj   | 13 +++
 ioptions-validation-minivalidation/Program.cs | 88 +++++++++++++++++++
 .../Properties/launchSettings.json            | 28 ++++++
 .../appsettings.json                          | 15 ++++
 4 files changed, 144 insertions(+)
 create mode 100644 ioptions-validation-minivalidation/IOptionsValidationMiniValidation.csproj
 create mode 100644 ioptions-validation-minivalidation/Program.cs
 create mode 100644 ioptions-validation-minivalidation/Properties/launchSettings.json
 create mode 100644 ioptions-validation-minivalidation/appsettings.json

diff --git a/ioptions-validation-minivalidation/IOptionsValidationMiniValidation.csproj b/ioptions-validation-minivalidation/IOptionsValidationMiniValidation.csproj
new file mode 100644
index 0000000..94077f2
--- /dev/null
+++ b/ioptions-validation-minivalidation/IOptionsValidationMiniValidation.csproj
@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="MiniValidation" Version="0.7.4" />
+  </ItemGroup>
+
+</Project>
diff --git a/ioptions-validation-minivalidation/Program.cs b/ioptions-validation-minivalidation/Program.cs
new file mode 100644
index 0000000..39ce2e5
--- /dev/null
+++ b/ioptions-validation-minivalidation/Program.cs
@@ -0,0 +1,88 @@
+using System.ComponentModel.DataAnnotations;
+using Microsoft.Extensions.Options;
+using MiniValidation;
+
+var builder = WebApplication.CreateBuilder(args);
+
+builder.Services.AddOptions<MySettings>()
+    .BindConfiguration("MySettings")
+    .ValidateMiniValidation() // <- Enable validation
+    .ValidateOnStart(); // <- Validate on app start
+
+// Explicitly register the settings object by delegating to the IOptions object
+builder.Services.AddSingleton(resolver => 
+        resolver.GetRequiredService<IOptions<MySettings>>().Value);
+
+var app = builder.Build();
+
+// app.MapGet("/", (IOptions<MySettings> options) => options.Value);
+app.MapGet("/", (MySettings options) => options);
+
+app.Run();
+
+public class MySettings
+{
+    [Required]
+    public string DisplayName { get; set; }
+
+    [Required]
+    public NestedSettings Nested { get; set; }
+
+    public class NestedSettings
+    {
+        [Required]
+        public string Value { get; set; }
+
+        [Range(1, 100)]
+        public int Count { get; set; }
+    }
+}
+
+public static class MiniValidationExtensions
+{
+    public static OptionsBuilder<TOptions> ValidateMiniValidation<TOptions>(
+        this OptionsBuilder<TOptions> optionsBuilder) where TOptions : class
+    {
+        optionsBuilder.Services.AddSingleton<IValidateOptions<TOptions>>(
+            new MiniValidationValidateOptions<TOptions>(optionsBuilder.Name));
+        return optionsBuilder;
+    }
+}
+
+    public class MiniValidationValidateOptions<TOptions>
+        : IValidateOptions<TOptions> where TOptions : class
+    {
+        public MiniValidationValidateOptions(string? name)
+        {
+            Name = name;
+        }
+
+        public string? Name { get; }
+
+        public ValidateOptionsResult Validate(string? name, TOptions options)
+        {
+            // Null name is used to configure all named options.
+            if (Name != null && Name != name)
+            {
+                // Ignored if not validating this instance.
+                return ValidateOptionsResult.Skip;
+            }
+
+            // Ensure options are provided to validate against
+            ArgumentNullException.ThrowIfNull(options);
+
+            if (MiniValidator.TryValidate(options, out var validationErrors))
+            {
+                return ValidateOptionsResult.Success;
+            }
+
+            var typeName = options.GetType().Name;
+            var errors = new List<string>();
+            foreach (var (member, memberErrors) in validationErrors)
+            {
+                errors.Add($"DataAnnotation validation failed for '{typeName}' member: '{member}' with errors: '{string.Join("', '", memberErrors)}'.");
+            }
+
+            return ValidateOptionsResult.Fail(errors);
+        }
+    }
diff --git a/ioptions-validation-minivalidation/Properties/launchSettings.json b/ioptions-validation-minivalidation/Properties/launchSettings.json
new file mode 100644
index 0000000..cf6f48b
--- /dev/null
+++ b/ioptions-validation-minivalidation/Properties/launchSettings.json
@@ -0,0 +1,28 @@
+{
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:27028",
+      "sslPort": 44379
+    }
+  },
+  "profiles": {
+    "StronglyTypedValidation": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "applicationUrl": "https://localhost:7282;http://localhost:5101",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}
diff --git a/ioptions-validation-minivalidation/appsettings.json b/ioptions-validation-minivalidation/appsettings.json
new file mode 100644
index 0000000..9d46e9d
--- /dev/null
+++ b/ioptions-validation-minivalidation/appsettings.json
@@ -0,0 +1,15 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*",
+  "MySettings": {
+    "DisplayName": "Display",
+    "Nested" : {
+      "Count": 0
+    }
+  }
+}