IHttpContextAccessor resolved as null

[JakeGinnivan]

I am using IdentityServer3 with dotnet core and am upgrading to RC2 and have hit a snag.

I have a custom user service which I want to resolve out of the aspnet core container. So I get access to the Request services like this:

var idsrvOptions = new IdentityServerOptions
{
    Factory = new IdentityServerServiceFactory
    {
        UserService = new Registration<IUserService>(r =>
        {
            var owin1 = r.Resolve<OwinEnvironmentService>();
            var httpContext1 = (HttpContext) owin1.Environment["Microsoft.AspNetCore.Http.HttpContext"];
            return httpContext1.RequestServices.GetService<CustomUserService>();
        })
    }
...

Not pretty, but I couldn't figure out how else to go from identity servers internal container to the request container without doing this. It calls into my factory fine:

services.AddScoped(p =>
{
    var httpContextAccessor = p.GetService<IHttpContextAccessor>();
    var portalOptions = p.GetService<IOptions<AuthenticationApiOptions>>();
    return new IdentityStoresApi(
        portalOptions,
        _portalApiHandler(),
        httpContextAccessor,
        _selfApiHandler);
});

Inside the AddScoped callback, httpContextAccessor is null. Any ideas what I have missed? The options are resolved fine.

[khellang]

In RC2, IHttpContextAccessor isn't registered by default. You have to register it yourself, explicitly; https://github.com/aspnet/Mvc/blob/dd774366f6fb18af9382ca84c276e6eb73c66b3a/test/WebSites/BasicWebSite/Startup.cs#L23

Related: aspnet/Razor#768, aspnet/Mvc#3936

I really think it's time there's an announcement for this... See aspnet/Mvc#3936 (comment) // @Eilon

[manikandan05]

Following is my startup.cs file code snippet

` public void ConfigureServices(IServiceCollection services)
{
// Add framework services.
services.AddDbContext(options =>
options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

        services.AddIdentity<ApplicationUser, IdentityRole>()
            .AddEntityFrameworkStores<ApplicationDbContext>()
            .AddDefaultTokenProviders();

        services.AddMvc();
        services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
        services.AddSingleton<IActionContextAccessor, ActionContextAccessor>();
        //services.AddCaching();
        services.AddSession();
        // Add application services.
        services.AddTransient<IEmailSender, AuthMessageSender>();
        services.AddTransient<ISmsSender, AuthMessageSender>();
    }`

I'm unable to get Httpcontext in my static class

` public static class TestHelper
{
public static IHttpContextAccessor HttpContextAccessor;

    public static void Configure(IHttpContextAccessor httpContextAccessor)
    {
        HttpContextAccessor = httpContextAccessor;
    }

public static string UrlFinder(this IHtmlHelper helper, string controlid)
{
HttpContextAccessor httpContextObj = new HttpContextAccessor();
//This line worked in RC1
var urlHelper = httpContextObj.HttpContext.RequestServices.GetRequiredService();
};
}

`

I already tried the steps said in following link comments

1. Can't resolve IHttpContextAccessor, IActionContextAccessor, IUrlHelper in RC2 Mvc#3936
2. HttpContext returns null for Httpcontextaccessor instance in RC2 Razor#768

Please help us to find out solution.

[khellang]

@manikandan05 You can't just create an instance of HttpContextAccessor and expect it to know about the current HttpContext. You need to get it from the container. That's why you're registering it.

[manikandan05]

Hi @khellang , I just want to get the urlHelper for my action. I tried out get the value from the below mentioned way.

var urlHelper = httpContextObj.HttpContext.RequestServices.GetRequiredService<IUrlHelper>();

[JakeGinnivan]

@khellang so the behaviour of the DI in core is to return null when things are not registered rather than throw an error? That seems broken =/

I didn't even check for it not being registered because I assumed if something is not registered it would throw saying it cannot resolve.

[khellang]

@JakeGinnivan Yes, when calling GetService. If you want to make sure it throws for invalid configurations, you need to call GetRequiredService 😄

[khellang]

@manikandan05 I'm not sure what you're trying to do. You want to resolve IHtmlHelper from the services? You already have it as a parameter?

You could do something like

public static class TestHelper
{
    public static string UrlFinder(this IHtmlHelper helper, string controlid)
    {
        var httpContext = helper.ViewContext.HttpContext;

        // Do something with httpContext...
    }
}

BTW, it sounds like you want to get the URL for something. You know there's already a utility called IUrlHelper?

[JakeGinnivan]

Sweet, i'm all sorted. will leave this issue open for @manikandan05

[JakeGinnivan]

Gonna close this, @manikandan05's issue doesn't seem to be related.

[manikandan05]

Hi @JakeGinnivan, still i'm trying to resolve from my end. i didn't get solution for get the value from IUrlHelper in GetRequiredService<>()

[khellang]

@manikandan05 I suggest you file a separate issue with a good description of what you're trying to achieve and why it's not working. It doesn't seem related to this...

[manikandan05]

Hi @khellang, i have tried your solution also, but i'm cant escape from this UrlHelper. Now i have the face some other problem.

Please help to find out the solution.

[khellang]

I'd prefer not to download and unpack a random zip on my computer. Can you post it as a gist or something? Create a GitHub repo?

It would be nice if you could try to explain what you're trying to achieve. Or provide more info on what's wrong. 😄

[manikandan05]

Hi @khellang, I have posted my code snippet (gist) in the following online link.

https://gist.github.com/manikandan05/5fa6bc50ae739675834fa75ec5025024

[khellang]

@manikandan05 I've basically give you the solution above. Get the HttpContext from the IHtmlHelper: helper.ViewContext.HttpContext

[manikandan05]

ok @khellang , After HttpContext, i'm not further using RequestServices.GetRequiredService<>() get the UrlHelper value to call Action(controller,method). This is the issue form my starting point.

[khellang]

@manikandan05 I still can't remember reading what your original issue is. Are you not getting the IUrlHelper from the services? Can't you just create it? new UrlHelper(helper.ViewContext)

[manikandan05]

Hi @khellang, Thanks for your valuable suggestion. Now i got the solution 😄

Thanks...