Optional appsettings.local.json in (new format) visual studio project

Question

My app uses appsettings.json for some settings. If appsettings.local.json is present, that should override appsettings.json for whatever settings it contains. So far, no problem.

But I use git for version control. Obviously, I don't want other users pulling down my local settings. So I git ignore appsettings.json.

Furthermore, there are a lot of projects in the solution. They share the same settings. So there is an appsettings.json at the solution level, and all the projects include it as a link.

Still fine, except for one thing. In order to be usable, I have to copy appsettings.local.json over to the output directory. But it shouldn't be in version control. So if someone clones the solution fresh they won't have it. That ought to be fine, but it isn't. VS. says "this file should be linked, but where the heck is it?" build error.

How can I deal with that?

Answer 1

With v2 this is dead simple.

1. Add an appsettings.local.json to your project (it should nest itself below the main appsettings.json file).
2. Add appsettings.local.json to your .gitignore

3. In your startup.cs within the constructor do the following:

   public class Startup
   {
       public IConfigurationRoot Configuration { get; }
   
       public Startup(IHostingEnvironment env)
       {
           var builder = new ConfigurationBuilder()
               .SetBasePath(env.ContentRootPath)
               .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true) //load base settings
               .AddJsonFile("appsettings.local.json", optional: true, reloadOnChange: true) //load local settings
               .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true) //load environment settings
               .AddEnvironmentVariables();
   
           Configuration = builder.Build();
       }
   
       /*
        * rest of your startup.cs
        */
   }
   

Answer 2

For .Net Core >2.1 you can simply chain the extension method ConfigureAppConfiguration(Action<WebHostBuilderContext, IConfigurationBuilder> configureDelegate) to your WebHost. Here is an example:

WebHost.CreateDefaultBuilder(args)
    .ConfigureAppConfiguration((hostingContext, config) =>
    {
        config.AddJsonFile(
            "appsettings.Local.json",
             optional: true,
             reloadOnChange: true);
    })
    // ...

And of course ignore the appsettings.Local.json in your .gitignore.