Advanced - Access HttpContext

In this article

Access HttpContext from Razor Pages

public class IndexModel : PageModel
{
    public void OnGet()
    {
        var message = HttpContext.Request.PathBase;

        // ...
    }
}

@page
@model IndexModel

@{
    var message = HttpContext.Request.PathBase;

    // ...
}

Access HttpContext from a Razor view in MVC

@{
    var username = Context.User.Identity.Name;

    // ...
}

Access HttpContext from a controller

public class HomeController : Controller
{
    public IActionResult About()
    {
        var pathBase = HttpContext.Request.PathBase;

        // ...

        return View();
    }
}

Access HttpContext from minimal APIs

app.MapGet("/", (HttpContext context) => context.Response.WriteAsync("Hello World"));

Access HttpContext from middleware

public class MyCustomMiddleware
{
    // ...

    public async Task InvokeAsync(HttpContext context)
    {
        // ...
    }
}

Access HttpContext from SignalR

public class MyHub : Hub
{
    public async Task SendMessage()
    {
        var httpContext = Context.GetHttpContext();

        // ...
    }
}

Access HttpContext from gRPC methods

Access HttpContext from custom components

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllersWithViews();
builder.Services.AddHttpContextAccessor();
builder.Services.AddTransient<IUserRepository, UserRepository>();

• UserRepository declares its dependency on IHttpContextAccessor.

• The dependency is supplied when DI resolves the dependency chain and creates an instance of UserRepository.

public class UserRepository : IUserRepository
{
    private readonly IHttpContextAccessor _httpContextAccessor;

    public UserRepository(IHttpContextAccessor httpContextAccessor) =>
        _httpContextAccessor = httpContextAccessor;

    public void LogCurrentUser()
    {
        var username = _httpContextAccessor.HttpContext.User.Identity.Name;

        // ...
    }
}

HttpContext access from a background thread

Note If your app generates sporadic NullReferenceException errors, review parts of the code that start background processing or that continue processing after a request completes. Look for mistakes, such as defining a controller method as async void.

• Copy the required data during request processing.

• Pass the copied data to a background task.

• Do not reference HttpContext data in parallel tasks. Extract the data needed from the context before starting the parallel tasks.

public class EmailController : Controller
{
    public IActionResult SendEmail(string email)
    {
        var correlationId = HttpContext.Request.Headers["X-Correlation-Id"].ToString();

        _ = SendEmailCoreAsync(correlationId);

        return View();
    }

    private async Task SendEmailCoreAsync(string correlationId)
    {
        // ...
    }
}

IHttpContextAccessor/HttpContext in Razor components (Blazor)

[CascadingParameter]
public HttpContext? HttpContext { get; set; }

Ref: Access HttpContext in ASP.NET Core