RealSense.DomainBasedConfig 1.1.0

How to use

1. Add the following section to your .config file

<configuration>
	<configSections>
		<section name="domainBasedConfig" type="RealSense.DomainBasedConfig.DomainBasedConfigSection, RealSense.DomainBasedConfig" allowLocation="true" allowDefinition="Everywhere" />
	</configSections>
</configuration>

2. Add the following section to your .config file

<configuration>
	<domainBasedConfig>
		<domains>
			<add domain="localhost" port="3000" map="DevEnv" />
			<add domain="test1.example.com" map="Test1Env" />
			<add domain="example.com" map="LiveEnv" />
			<add domain="www.example.com" map="LiveEnv" />
		</domains>
		<environments>
			<add name="DevEnv">
				<database server="(local)" database="Dev1" />
				<settings>
					<add name="Setting1" value="Apple" />
					<add name="Setting2" value="Cheese" />
				</settings>
			</add>
			<add name="Test1Env">
				<database server="(local)" database="Test1" />
				<settings>
					<add name="Setting1" value="Grape" />
					<add name="Setting2" value="Egg" />
				</settings>
			</add>
			<add name="LiveEnv">
				<database server="(local)\MSSQL2020" database="LiveDatabase" />
				<settings>
					<add name="Setting1" value="Plum" />
					<add name="Setting2" value="Date" />
				</settings>
			</add>
		</environments>
</configuration>

NOTE: The <domains> section is only required for Web Applications and provides automatic resolution of which environment to use based on the HttpContext.Request details. For console applications (for example) you can request settings and connection strings by stating the environment name.

3. Access to a connection string from Entity Framework is done adding a new partial class that implements a static method as follows:

	using System;
	using System.Collections.Generic;
	using System.Linq;
	using System.Web;

	namespace WebService
	{
		public partial class MyEntities
		{
			/// <summary>
			/// Initializes a new instance using a modified connection string 
			/// based on host name.
			/// </summary>
			public static MyEntities CreateDomainBased()
			{
				string s = RealSense.DomainBasedConfig.Instance.GetHttpConnectionString("MyEntities");
				return new MyEntities(s);
			}
		}
	}

4. Change your Entity Framework instantiation from

	using (var ctx = new MyEntities())
	{
	}

TO:

	using (var ctx = MyEntities.CreateDomainBased())
	{
	}

Example Application

// Program.cs
using Inst = RealSense.DomainBasedConfig.Instance;
using Debug = System.Diagnostics.Debug;

namespace TestDomainBasedConfig
{
	internal class Program
	{
		private static void Main(string[] args)
		{
			Debug.WriteLine("1) Dump Config");
			Debug.WriteLine(Inst.DumpConfig());

			Debug.WriteLine("2) Get Environment (valid)");
			var env1 = Inst.GetEnvironment("Dev2Env");
			Debug.WriteLine(env1);

			Debug.WriteLine("3) Get Configuration String \"Stock\" under \"Dev2Env\"");
			Debug.WriteLine(Inst.GetEnvConnectionString("Stock", "Dev2Env"));

			Debug.WriteLine("4) Get Setting from Environment (env1) (will throw if setting doesn't exist)");
			var v1 = env1.Settings["Setting1"];
			Debug.Assert(v1 == "Strawberry");
			Debug.WriteLine($"Setting1=\"{v1}\" under \"{env1.Name}\" environment..");

			Debug.WriteLine("5) Safely get non-existant Setting from Environment (env1) (returns provided defaultValue or null if doesn't exist)");
			var value2 = env1.Settings.Get("Setting2");
			Debug.Assert(value2 == null);
			t = value2 ?? "(null)";
			Debug.WriteLine($"Setting Setting2: {t}");

			Debug.WriteLine("7) Get Environment based on HttpContext");
			// NOTE: will throw for non-web applications as HttpContext.Current will be null
			try
			{
				var env3 = Inst.GetEnvironmentFromHttp();
				Debug.Assert(env3 != null);
			}
			catch (RealSense.DomainBasedConfig.NonHttpEnvironmentException ex)
			{
				Debug.WriteLine(ex.Message);
			}

			Debug.WriteLine("8) Get Connection String based on HttpContext");
			// NOTE: This will throw for non-web applications as HttpContext.Current will be null
			try
			{
				var connString2 = Inst.GetHttpConnectionString("HumanResources");
				Debug.Assert(connString2 != null);
			}
			catch (RealSense.DomainBasedConfig.NonHttpEnvironmentException ex)
			{
				Debug.WriteLine(ex.Message);
			}

			Debug.WriteLine("9) Enumerate settings in an environment");
			Debug.WriteLine($"Settings for {env1.Name} environment:");
			foreach(var setting in env1.Settings)
				Debug.WriteLine($" - {setting.Key} => {setting.Value}");
			Debug.WriteLine($"Settings for Test1Env environment:");
			foreach(var setting in Inst.GetEnvironment("Test1Env").Settings)
				Debug.WriteLine($" - {setting.Key} => {setting.Value}");

			Debug.WriteLine("10) Enumerate all Settings for all Environments");
			Debug.WriteLine($"Enumerate all settings:");
			foreach (var env in Inst.GetConfig().Environments)
			{
				Debug.WriteLine($" - Environment: {env.Key}");
				foreach (var setting in env.Value.Settings)
					Debug.WriteLine($" - - {setting.Key} => {setting.Value}");
			}

			Debug.WriteLine("11) Enumerate all Connection Strings for all Environments");
			var csList = new string[] { "Stock", "Marketing", "HumanResources", "Development" };
			Debug.WriteLine($"Enumerate all connection strings:");
			foreach (var env in Inst.GetConfig().Environments)
			{
				var db = env.Value.Database;
				Debug.WriteLine($" - Environment: {env.Key}; Database: {db}");
				foreach (var cs in csList)
				{
					var str = Inst.GetEnvConnectionString(cs, env.Key);
					Debug.WriteLine($" - - {cs} => {str}");
				}
			}
		}
	}
}

// App.config
<?xml version="1.0" encoding="utf-8"?>
<configuration>
	<configSections>
		<section name="domainBasedConfig" type="RealSense.DomainBasedConfig.DomainBasedConfigSection, RealSense.DomainBasedConfig" allowLocation="true" allowDefinition="Everywhere" />
	</configSections>
	<startup>
		<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6" />
	</startup>
	<connectionStrings>
		<remove name="LocalSqlServer" />
		<add name="Stock" connectionString="Data Source=xxxxxxx;Initial Catalog=xxxxxxx;Integrated Security=True;MultipleActiveResultSets=True" providerName="System.Data.SqlClient" />
		<add name="HumanResources" connectionString="metadata=res://HumanResources/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=xxxxxxx;Initial Catalog=xxxxxxx;Integrated Security=True;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" />
	</connectionStrings>
	<domainBasedConfig>
		<domains>
			<add domain="localhost" port="3000" map="Dev1Env" />
			<add domain="example.com" map="LiveEnv" />
			<add domain="www.example.com" map="LiveEnv" />
		</domains>
		<environments>
			<add name="Dev1Env">
				<database server="(local)" database="Dev2Database" />
				<settings>
					<add name="Setting1" value="Strawberry" />
					<add name="Setting2" value="Pear" />
				</settings>
			</add>
			<add name="LiveEnv">
				<database server="(local)\MSSQL2020" database="LiveDatabase" />
				<settings>
					<add name="Setting1" value="Plum" />
					<add name="Setting2" value="Date" />
				</settings>
			</add>
		</environments>
	</domainBasedConfig>
</configuration>