Add MapConfiguration

Directory.Build.props

@@ -19,7 +19,7 @@
     <!-- Embed source files that are not tracked by the source control manager in the PDB -->
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
 
-    <LangVersion>10.0</LangVersion>
+    <LangVersion>12.0</LangVersion>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>

src/NetLah.Extensions.Configuration/ConfigurationBuilderBuilder.cs

@@ -189,6 +189,11 @@ public ConfigurationBuilderBuilder WithTransformConfiguration(string sectionKey
         return WithAddPostConfiguration(builder => builder.AddTransformConfiguration(sectionKey));
     }
 
+    public ConfigurationBuilderBuilder WithMapConfiguration(string sectionKey = "MapConfiguration")
+    {
+        return WithAddPostConfiguration(builder => builder.AddMapConfiguration(sectionKey));
+    }
+
     public static ConfigurationBuilderBuilder Create<TStartup>(string[]? args = null)
         => new ConfigurationBuilderBuilder()
             .WithCommandLines(args)

src/NetLah.Extensions.Configuration/ConfigurationBuilderExtensions.cs

@@ -24,6 +24,23 @@ public static TConfigurationBuilder AddTransformConfiguration<TConfigurationBuil
         return configBuilder;
     }
 
+    public static TConfigurationBuilder AddMapConfiguration<TConfigurationBuilder>(this TConfigurationBuilder configBuilder, string sectionKey = "MapConfiguration")
+        where TConfigurationBuilder : IConfigurationBuilder
+    {
+        if (string.IsNullOrWhiteSpace(sectionKey))
+        {
+            throw new ArgumentException($"{nameof(sectionKey)} is required", nameof(sectionKey));
+        }
+
+        var configuration = configBuilder is IConfigurationRoot configurationRoot
+            ? configurationRoot
+            : configBuilder.Build();
+
+        configBuilder.Add(new MapConfigurationSource(configuration, sectionKey));
+
+        return configBuilder;
+    }
+
     public static TConfigurationBuilder AddAddFileConfiguration<TConfigurationBuilder>(this TConfigurationBuilder configBuilder, Action<AddFileConfigurationSourceOptions>? configureOptions = null, string sectionKey = "AddFile", bool? throwIfNotSupport = null)
         where TConfigurationBuilder : IConfigurationBuilder
     {

src/NetLah.Extensions.Configuration/MapConfigurationProvider.cs

@@ -0,0 +1,64 @@
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Primitives;
+
+namespace NetLah.Extensions.Configuration;
+
+public class MapConfigurationProvider(MapConfigurationSource source) : ConfigurationProvider
+{
+    private readonly MapConfigurationSource _source = source;
+    private object? _lock = null;
+    private IChangeToken? _token;
+    private IConfigurationSection? _configurationSection;
+
+    private void OnChange(object? obj)
+    {
+        Data.Clear();
+        InternalLoad();
+        OnReload();
+    }
+
+    public override void Load()
+    {
+        InternalLoad();
+
+        if (_configurationSection != null && Interlocked.CompareExchange(ref _lock, new object(), null) == null)
+        {
+            _token = _configurationSection.GetReloadToken();
+            _token.RegisterChangeCallback(OnChange, this);
+        }
+    }
+
+    private void InternalLoad()
+    {
+        var configuration = _source.Configuration;
+        _configurationSection ??= configuration.GetSection(_source.SectionKey);
+
+        foreach (var item in _configurationSection.GetChildren())
+        {
+            if (item.Value is { } keyValue)
+            {
+                TryParse(keyValue);
+            }
+            else
+            {
+                var key1 = item["From"] ?? item["Source"];
+                var key2 = item["To"] ?? item["Destination"] ?? item["Dest"];
+                if (!string.IsNullOrEmpty(key1) && !string.IsNullOrEmpty(key2) && configuration[key1] is { } value)
+                {
+                    Data[key2] = value;
+                }
+            }
+        }
+
+        void TryParse(string keyValue)
+        {
+            var pos = keyValue.IndexOf('=');
+            var key1 = keyValue[..pos];
+            var key2 = keyValue[(pos + 1)..];
+            if (configuration[key1] is { } value)
+            {
+                Data[key2] = value;
+            }
+        }
+    }
+}

src/NetLah.Extensions.Configuration/MapConfigurationSource.cs

@@ -0,0 +1,15 @@
+using Microsoft.Extensions.Configuration;
+
+namespace NetLah.Extensions.Configuration;
+
+public class MapConfigurationSource(IConfiguration configuration, string sectionKey) : IConfigurationSource
+{
+    public IConfiguration Configuration { get; } = configuration;
+
+    public string SectionKey { get; } = sectionKey;
+
+    public IConfigurationProvider Build(IConfigurationBuilder builder)
+    {
+        return new MapConfigurationProvider(this);
+    }
+}

test/NetLah.Extensions.Configuration.Test/ConfigurationBuilderBuilderTest.cs

@@ -94,12 +94,15 @@ private static void AssertProduction(IConfiguration configuration)
     {
         Assert.Equal("MainValue1", configuration["MainKey"]);
         Assert.Equal("EnvironmentProductionValue1", configuration["EnvironmentKey"]);
+        Assert.Equal("ProductionSubValue1", configuration["ProductionSection:SubKey"]);
+        Assert.Null(configuration["SecondaryKey"]);
     }
 
     private static void AssertDevelopment(IConfiguration configuration)
     {
         Assert.Equal("MainValue1", configuration["MainKey"]);
         Assert.Equal("EnvironmentDevelopmentValue1", configuration["EnvironmentKey"]);
+        Assert.Equal("DevelopmentSubValue1", configuration["DevelopmentSection:SubKey"]);
     }
 
     private static void AssertCommandLines(IConfiguration configuration)
@@ -564,7 +567,9 @@ public void Build_Production_changeTo_dev_Success()
                 null,
             });
 
-        AssertDevelopment(configuration2);
+        Assert.Equal("MainValue1", configuration2["MainKey"]);
+        Assert.Equal("EnvironmentDevelopmentValue1", configuration2["EnvironmentKey"]);
+        Assert.Null(configuration2["DevelopmentSection:SubKey"]);
         AssertCommandLines(configuration2);
     }
 
@@ -1433,4 +1438,60 @@ public void AddFileConfigurationProduction_KeyPerFile_Handler()
         Assert.Equal("Key-Per-File/mainValue line0", configuration["MainKey"]);
         Assert.Equal("KeyPerFileSection__Add-File-Source.txt", configuration["KeyPerFileSection:Add-File-Source"]);
     }
+
+    [Fact]
+    public void EnvironmentNameMapConfiguration()
+    {
+        var configuration = ConfigurationBuilderBuilder.Create(["/CommandLineSection:SubKey=CommandLineSection-SubKeyValue"])
+            .WithEnvironment("Map")
+            .WithMapConfiguration()
+            .BuildConfigurationRoot();
+
+        AssertProviders(configuration, new[] {
+                "JsonConfigurationProvider",
+                "JsonConfigurationProvider",
+                "EnvironmentVariablesConfigurationProvider",
+                "CommandLineConfigurationProvider",
+                "MapConfigurationProvider",
+            }, new[] {
+                "appsettings.json",
+                "appsettings.Map.json",
+                null,
+                null,
+                null,
+            });
+
+        Assert.Equal("MainValue1", configuration["MainKey"]);
+        Assert.Equal("MainValue1", configuration["SecondaryKey"]);
+        Assert.Equal("CommandLineSection-SubKeyValue", configuration["CommandLineSection:SubKey"]);
+        Assert.Equal("CommandLineSection-SubKeyValue", configuration["MapSection:SubKey"]);
+    }
+
+    [Fact]
+    public void ConfigurationBuilder_EnvironmentNameMapConfiguration()
+    {
+        var configuration = CreateDefaultBuilder(["/CommandLineSection:SubKey=CommandLineSection-SubKeyValue"], "Map")
+            .AddMapConfiguration()
+            .Build();
+
+        AssertProviders(configuration, [
+                "JsonConfigurationProvider",
+                "JsonConfigurationProvider",
+                "EnvironmentVariablesConfigurationProvider",
+                "CommandLineConfigurationProvider",
+                "MapConfigurationProvider",
+            ], [
+                "appsettings.json",
+                "appsettings.Map.json",
+                null,
+                null,
+                null,
+            ]);
+
+        Assert.Equal("MainValue1", configuration["MainKey"]);
+        Assert.Equal("MainValue1", configuration["SecondaryKey"]);
+        Assert.Equal("CommandLineSection-SubKeyValue", configuration["CommandLineSection:SubKey"]);
+        Assert.Equal("CommandLineSection-SubKeyValue", configuration["MapSection:SubKey"]);
+    }
+
 }

test/NetLah.Extensions.Configuration.Test/appsettings.Development.json

@@ -1,3 +1,6 @@
 {
-  "EnvironmentKey": "EnvironmentDevelopmentValue1"
+  "EnvironmentKey": "EnvironmentDevelopmentValue1",
+  "DevelopmentSection": {
+    "SubKey": "DevelopmentSubValue1"
+  }
 }

test/NetLah.Extensions.Configuration.Test/appsettings.Map.json

@@ -0,0 +1,9 @@
+{
+  "MapConfiguration": [
+    "MainKey=SecondaryKey",
+    {
+      "From": "CommandLineSection:SubKey",
+      "To": "MapSection:SubKey"
+    }
+  ]
+}

test/NetLah.Extensions.Configuration.Test/appsettings.Production.json

@@ -1,3 +1,6 @@
 {
-  "EnvironmentKey": "EnvironmentProductionValue1"
+  "EnvironmentKey": "EnvironmentProductionValue1",
+  "ProductionSection": {
+    "SubKey": "ProductionSubValue1"
+  }
 }