Transferring data between Middleware in Asp.net Core

The "HttpContext" object in ASP.NET Core allows you to transport data between middleware. A single HTTP request's context is represented by the "HttpContext," which also contains data on the request and response.
Depending on your unique use case, there are different ways to transport data between middleware. Here are some strategies you can use:

Route values or Query Parameters:

Using query parameters or route values, middleware can communicate data amongst each other. From the request URL, the information can be taken out and used in later middleware. For instance:

   // Middleware 1
   public async Task Invoke(HttpContext context)
   {
       // Get data from query parameter
       string data = context.Request.Query["data"];

       // Pass data to next middleware
       context.Items["data"] = data;

       await _next(context);
   }
   // Middleware 2
   public async Task Invoke(HttpContext context)
   {
       // Get data from previous middleware
       string data = context.Items["data"] as string;

       // Use the data

       await _next(context);
   }

Session State:

Data can be kept in the session and accessed by later middlewares. Make sure your ASP.NET Core application has session state configured. For instance:

   // Middleware 1
   public async Task Invoke(HttpContext context)
   {
       // Store data in session
       context.Session.SetString("data", "value");

       await _next(context);
   }

   // Middleware 2
   public async Task Invoke(HttpContext context)
   {
       // Retrieve data from session
       string data = context.Session.GetString("data");

       // Use the data

       await _next(context);
   }

“HttpContext.Items”: Data that is specific to the current request but not persisted across subsequent requests can be stored in the "HttpContext.Items" dictionary. For instance:

   // Middleware 1
   public async Task Invoke(HttpContext context)
   {
       // Store data in HttpContext.Items
       context.Items["data"] = "value";

       await _next(context);
   }

   // Middleware 2
   public async Task Invoke(HttpContext context)
   {
       // Retrieve data from HttpContext.Items
       string data = context.Items["data"] as string;

       // Use the data

       await _next(context);
   }

These are just a few instances of how ASP.NET Core allows you to transmit data between middlewares. The method chosen will depend on the type of data being used and the particular needs of your application.