aspnet core dependency injection with IOptions in startup - asp.net-core

Question

What is going on gang?
I am looking for a proper and clean way of injecting configuration into my classes using the IOptions package. Currently, I am registering all the configuration object in one place and everything is just fine. The problem is with some classes that I need to register in the startup method.
The initial method implementation looks like this: (extension method)
public static void RegisterHttpClients(this IServiceCollection services, AppSettings appSettings)
{
services.AddHttpClient<IPdfService, PdfService>(
httpClient => httpClient.DefaultRequestHeaders.Add("PdfApiKey", appSettings.PdfApiKey));
}
This AppSettings object I am also injecting into other classes using IOptions so would like to somehow reuse the object from there instead of having to get same object from json again like that:
var appSettings = Configuration.GetSection("AppSettings").Get<AppSettings>();
services.RegisterHttpClients(appSettings);
In other words - I already have the thing registered with services.Configure<AppSettings>(configuration.GetSection("AppSettings")); so would kind of like to piggy-back on this if possible.
Any thoughts/suggestions for possible directions on how to configure this?
EDIT: (added JSON and AppSettings files)
public class AppSettings
{
public string PdfApiKey {get; set;}
public string AnotherProperty {get; set;}
}
{
"AppSettings": {
"PdfApiKey": "SomeKey",
"AnotherProperty": "HollyTheCow"
}
}
Thanks in advance!

Answer 1

You can accomplish this by registering your options with Configure (which you've done), then using the second overload to AddHttpClient() to get the registered options from the DI container (Service Locator pattern). Note I've used IServiceProvider.GetRequiredService, but you can use IServiceProvider.GetService()?.Value if it's an optional setting.
services.Configure<AppSettings>(_configuration.GetSection("AppSettings"));
services.AddHttpClient<YourService>((serviceProvider, config) => {
var settings = serviceProvider.GetRequiredService<IOptions<AppSettings>>().Value;
config.BaseAddress = new Uri(settings.BaseUri);
});

Answer 2

Your code has no any error and will run successfully
There may be many appSetting.json files on your project.
Check the ASPNETCORE_ENVIRONMENTvariable on your project.
Right click on your project > Properties > Debug > Environment variables
if ASPNETCORE_ENVIRONMENT is set on Development IConfiguration read data from
appSettings.development.json and you should add AppSettigs json in appSettings.development.json
if ASPNETCORE_ENVIRONMENT is set on Production IConfiguration read data from
appSettings.production.json and you should add AppSettigs json in appSettings.production.json
if you want IConfiguration read data from appSetting.json delete both appSettings.development.json and appSettings.production.json file.
in this case IConfiguration by default read and bind data from appSetting.json
Another options
You can config your IConfiguration to load data dynamically from
appSettings.json like this
public Startup(IHostingEnvironment env)
{
var builder = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
.AddEnvironmentVariables();
this.configuration = builder.Build();
}