[Feature Request] Add a method to read a section with Downstream apis (.AddDownstreamApis(IConfigurationSection))

[jmprieur]

Why?

As developers use more IDownstreamApi, standardize the description of a collection of Downstream APIs, and register them all at once.

In the appsettings.json, customers could describe their APIs in a particular section, and Microsoft.Identity.Web should be able to add them all.

"AzureAd" : {
},

"DownstreamApi":
{
 "MyApi1": {
    "BaseUrl" : "https://myservice.com",
    "Scopes" : [ "access_as_admin" ],
    "RequestAppToken" : true
 },
 "MyApi2": {
    "BaseUrl" : "https://myOtherService.com",
    "Scopes" : [ "access_as_user" ],
 }
}

What?

Have an API, in DownstreamApiExtensions that takes a IConfigurationSection

services.AddDownstreamApis(Configuration.GetSection("DownstreamApis")

This would deserialize the section as a Dictionary<string, DownstreamApiOptions>, register the DownstreamApi service, and keep the Options in named options.

P2: Also add a method:

AddDownstrsamApis(IConfiguration, Action<Dictionary<string, DownstreamApiOptions>> configureOptions)

How

Dictionary<string, DownstreamApiOptions> dictionaryOfDownstreamApiOptionsByServiceName;

foreach(var optionsForService in dictionaryOfDownstreamApiOptionsByServiceName)
{
  services.Configure(optionsForService.Key, optionsForService.Value);
}
RegisterDownstreamApi(services)

[jennyf19]

#2782