README.md

AppSettingsSourceGenerator

Source generator that turns appsettings.json into ready to be used classes for dependency injection.

Installation

Use this NuGet package. Install using, for example, dotnet add package Reodor.AppSettingsSourceGenerator --version 1.0.0

Because of how source generators work in Visual Studio currently, you may have to restart Visual Studio after you first install the package in your project.

Note
Due to how analyzers need to be packaged when referencing external NuGet packages, your analyzer list in Visual Studio may appear cluttered with other libraries than just analyzers. For now, this is the only way to make this work.

How it works

Given an appsettings.json such as

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "MySettings": {
    "Test": "asdf",
    "Value": 1,
    "Exists": false
  }
}

the source generator will create three classes when you build your project:

• <YourTopNamespace>.AppSettings.Logging
• <YourTopNamespace>.AppSettings.MySettings
• <YourTopNamespace>.AppSettings.SimpleSettings

The resulting code looks like this (using MySettings from the above appsettings.json as an example)

#nullable enable
using System;
namespace DemoApp.AppSettings
{

    public partial class MySettings
    {
        public string Test { get; set; } = default!;
        public int Value { get; set; } = default!;
        public bool Exists { get; set; } = default!;
    }
}

The SimpleSettings class is a special one as it contains all simple valued settings such as "AllowedHosts": "*".

You can then add these to dependency injection like this:

builder.Services.Configure<DemoApp.AppSettings.MySettings>(builder.Configuration.GetSection("MySettings"));