.NET Core HttpContext is empty during getting DB name in Startup

Question

I have .NET Core app with dynamic DB, that I get from http request (subdomain). And I do the following in Startup.cs:

public void ConfigureServices(IServiceCollection services)
{
    services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();

    services.AddDbContext<AppDbContext>((serviceProvider, options) =>
    {
        var httpContext = serviceProvider.GetService<IHttpContextAccessor>().HttpContext;
        //todo get subdomain
                
        options.UseSqlServer(Configuration.GetConnectionString("DataContext").Replace(":dbname", dbName));
    });
    ...
}

But httpContext variable is null. Why is it null and how can I resolve it?

I looked at this link Dynamically change connection string in Asp.Net Core but it seems nothing works from there

I think you have to use an environment variable to store the dbname — ddfra, Sep 14 '21 at 20:46
@dofra I would be appreciate the example how it will work in my case. — A. Gladkiy, Sep 15 '21 at 07:07
yeah sure. Can you tell where you are deploying the application? On-Prem, Azure app service, docker? — ddfra, Sep 15 '21 at 07:57

score 1 · Answer 1 · answered Sep 14 '21 at 14:19

1

An HttpContext only exists when there is a request, that's why you won't get any outside of one.

answered Sep 14 '21 at 14:19

Ricardo Peres

13,724
5
57
74

Thanks @Ricardo, but what's the best way to get DB name in my case then? – A. Gladkiy Sep 14 '21 at 14:31
See the approach I followed in my library SharedFlat: https://weblogs.asp.net/ricardoperes/sharedflat-and-databases – Ricardo Peres Sep 14 '21 at 14:37

.NET Core HttpContext is empty during getting DB name in Startup

1 Answers1