How to replace the DataPortalProxy at an arbitrary time in the app lifecycle

[GreatBarrier86]

I have a question on this. In CSLA 5, we had the Csla.ApplicationContext.DataPortalProxy and Csla.ApplicationContext.DataPortalUrlString static properties that allowed changing the values at runtime (eg: switching from local to remote at an arbitrary time).

In principle, it doesn't appear that Dependency Injection supports that concept. Would you say changing the proxy/url is simply not a thing we could do anymore?

[GreatBarrier86]

I'm extraordinarily new to using Dependency Injection so i wasn't coming at this from the right angle. It occurs to me that while you can't replace services after you're registered them, there's nothing stopping me from using the Func<> parameter of each of the AddTransient calls to return what I need at DP request time to switch back and forth.

Would this be reasonable to you, @rockfordlhotka?

`

            services.AddTransient<HttpProxyOptions>(p =>
                    {
                        return new HttpProxyOptions { DataPortalUrl = CslaUtilities.DataPortalHelper.WebServiceUrl };
                    })
                    .AddTransient<HttpClient>()
                    .AddCsla()
                    .AddTransient<IDataPortalProxy>(p =>
                    {
                        var appCtx = p.GetRequiredService<Csla.ApplicationContext>();
                        if (CslaUtilities.DataPortalHelper.UseRemoteDataPortal)
                        {
                            var httpClient = p.GetRequiredService<HttpClient>();
                            var proxOps = p.GetRequiredService<HttpProxyOptions>();
                            return new CustomHttpProxy(appCtx, httpClient, proxOps);
                        }
                        else
                        {
                            return new LocalProxy(appCtx, new LocalProxyOptions());
                        }
                    });

`

[rockfordlhotka]

You are on the right track, but the specific solution won't work - at least not if you use the existing extension method:

csla/Source/Csla/DataPortalClient/HttpProxyExtensions.cs

Line 25 in ffa5f22

public static DataPortalClientOptions UseHttpProxy(this DataPortalClientOptions config, Action<Csla.Channels.Http.HttpProxyOptions> options)

The reason is that, in the default extension method, the HttpProxyOptions are directly created, they aren't created as a service.

I think what you want is to change how the actual HttpProxy is created and initialized. Basically DO NOT use the existing UseHttpProxy extension method, and instead create your own implementation that sets up the HttpProxyOptions as necessary for each call.

[GreatBarrier86]

Where am I using UseHttpProxy? Maybe I misunderstand.

[rockfordlhotka]

In Program.cs on the client, where you call something like services.AddCsla() you'll call other configuration elements for CSLA, usually including setting the data portal proxy.

From BlazorExample:

builder.Services.AddCsla(o => o
  .AddBlazorWebAssembly()
  .DataPortal(dpo => dpo
    .EnableSecurityPrincipalFlowFromClient()
    .UseHttpProxy(options => options.DataPortalUrl = "/api/DataPortal")));