Skip to main content

.Net Core Session Management



The Session helps to store user data in the application memory. Since the user data stores on the application it quick and fast to access. .Net Core Session data stored application using the cache, this cache can be either In-Memory or Distributed Cache. 

Session Work-flow:

  • On the user request the application from the browser, the server will create a session with an id called Session-Id. 
  • This Session-Id will be given to the user in response by storing it in the cookie. So on every next request, this cookie will reach to the application which contains Session-Id. 
  • An application uses the SessionId as the main key and stores all user data in the application cache. So by receiving a cookie from a client with Session-Id application will fetch the session stored data as per request. 
  • This cookie session is browser-specific it is not sharable between browsers. 
  • We can set session time out in our application, where after the time session data will get automatically cleared.

Create A Sample .Net Core MVC Application:

Let's create a sample MVC application to get hands-on for implementing and configuring the session in the application. To create a .Net Core MVC application you can use either Visual Studio 2019(Support .Net Core 3.0 +) or Visual Studio Code. Click here to understand the visual studio code to create a .Net Core Application.

Register Session:

Now register session service in application startup file as follows.
Startup.cs:(Inside of ConfigureService Method)
services.AddSession(options => {
	options.IdleTimeout = TimeSpan.FromMinutes(1);
	options.Cookie.HttpOnly = true;
	options.Cookie.IsEssential = true;
});
IdleTimeout - The IdleTimeout indicates how long the session can be idle before its content is abandoned. Each time session access will reset the timeout. This IdleTimeout only applies to session content on the server, not to the cookie which holds the session-id.
Cookie - The Cookie provides configuration for the cookie used to store the session-id.

Configure Session Middleware:

Now configure the session middleware in the startup file. It should be configured between the middleware like 'app.UseRouting()' and 'app.UseEndpoint()'.
Startup.cs:(Inside of Configure Method):

app.UseRouting();

app.UseSession();

app.UseEndpoints();

Check Session-Id:

We can check the Session-Id value from the 'HttpContext.Session.Id' as follows.
Controllers/TestController.cs:
using Microsoft.AspNetCore.Mvc;
namespace SessionMvc.App.Controllers
{

    [Route("test")]
    public class TestController:Controller
    {
        [HttpGet]
        [Route("get-sessionId")]
        public IActionResult GetSessionId()
        {
            return Content(HttpContext.Session.Id);
        }
    }
}

From the picture above we fetched Session-Id created by the application. But we can observe the session cookie was not created. The reason behind the session cookie not created, the application only stores the session on at least single user data to be stored in the session. So in this case, if the user requested application multiple times, on every request application creates a new session-id, since there was no session cookie.

Store And Fetch Data From Session:

Till now we haven't set and fetch data from the session. So to do that we have some predefined methods to set and fetch session data as follows.

'HttpContext.Session.Set(string key, byte[] value)' - In this, we need to pass one parameter like 'key' which of type string used for fetch stored data, and another parameter of type byte[](byte array) which our actual data to be stored in the session.
'HttpContext.Session.TryGetValue(string key, out byte[] value)' - In this, we need to pass a key-value to fetch the data stored in the session. Here it outputs the value as bytep[](byte array).

Here to save or fetch data we need to deal with a byte array of data. So to make communication easy and simple .Net provide extension method under 'Microsoft.AspNetCore.Http' library.

'HttpContext.Session.SetString(string key, string value)' - In this method both key and value(data to be stored) of type string.
'HttpContext.Session.GetString(string key)' - In this method on passing key, we get session stored data as of type string.

Controllers/TestController.cs:
using Microsoft.AspNetCore.Http;

namespace SessionMvc.App.Controllers
{
    [Route("test")]
    public class TestController : Controller
    {
        [HttpGet]
        [Route("save-to-session")]
        public IActionResult SaveToSession(string name)
        {
            HttpContext.Session.SetString("your_name", name);
            return Content($"{name} save to session");
        }

        [HttpGet]
        [Route("fetch-from-session")]
        public IActionResult FetchFromSession()
        {
            string name = HttpContext.Session.GetString("your_name");
            return Content(name);
        }
    }
}

On saving data to the session, the application adds the session id to cookie and return to the response, so on every next request application uses the session id to fetch the data from the session store until the data expired.

Fetching stored data looks as below.

Store Objects In Session:

Session storage follows the key-value pair dictionary process to save or fetch data. In this process, we have only available methods to store data either in form byte[](byte array) or string, there is no overloaded method to save object or class or entity of data directly into the session.

So to store the Objects in session let's implement custom extension methods as follows.
Utilities/SessionExtenstion.cs:
using System.Text.Json;
using Microsoft.AspNetCore.Http;

namespace SessionMvc.App.Utilities
{
    public static class SessionExtension
    {
        public static void Set<T>(this ISession session, string key, T value)
        {
            session.SetString(key, JsonSerializer.Serialize(value));
        }

        public static T Get<T>(this ISession session, string key)
        {
            var value = session.GetString(key);
            return value == null ? default : JsonSerializer.Deserialize<T>(value);
        }
    }
}
Here we can observe serializing the object to string type and saved it using existing methods like 'ISession.SetString(string key, string value)'.

So to test these extension methods, let's create a model and try to store it in session as follows.
Models/InfoModel.cs:
public class InfoModel
{
	public string Name { get; set; }
	public int Age { get; set; }
	public string Designation { get; set; }
}
Let's update our controller code as follows.
Controllers/TestController.cs:
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using SessionMvc.App.Models;
using SessionMvc.App.Utilities;

namespace SessionMvc.App.Controllers
{

    [Route("test")]
    public class TestController : Controller
    {
        [HttpGet]
        [Route("save-to-session")]
        public IActionResult SaveToSession()
        {
            var info = new InfoModel
            {
                Name = "Naveen",
                Age = 26,
                Designation = ".NET Developer"
            };
            HttpContext.Session.Set<InfoModel>("info", info);
            return Content($"save to session");
        }

        [HttpGet]
        [Route("fetch-from-session")]
        public IActionResult FetchFromSession()
        {
            InfoModel info = HttpContext.Session.Get<InfoModel>("info");
            return Content($"{info.Name} info fetched from session");
        }
    }
}

Clear Session:

'HttpContext.Session.Remove(string key)' - This method removes the given key from the session.

'HttpContext.Session.Clear()' - This method removes the all entries from the session.

Session Using SQL Distributed Cache:

For single-server applications saving session data in-memory of the application will work without any issue. But if an application hosted on multiple servers or nodes using then there is a chance of inconsistency with the application because the in-memory session is specific to the application which runs on a specific server, this in-memory can't be shared between multiple server or nodes.

So it is recommended to use DistributedCache to store the session data. We can use some of the DistributeCache stores like 'Redis', 'SQL Cache', 'NCache', etc. Here we going to use SQL cache to store the session data. Click here to know more about the Distributed SQL Cache, so here I'm going to show code snippet of SQL cache.

Let's install the following nugget to support the .NET Core SQL Cache.
.Net Core CLI Command:
dotnet add package Microsoft.Extensions.Caching.SqlServer
Click here to find the SQL script to generate the cache table.

Now to store the session data in the cache table we need to register SQL distributed service in the startup file.
Startup.cs:
services.AddDistributedSqlServerCache(options => {
	options.ConnectionString = Configuration.GetConnectionString("MyWorldDbConnection");
	options.SchemaName = "dbo";
	options.TableName = "MyCache";
	//options.ExpiredItemsDeletionInterval = TimeSpan.FromMinutes(6);
});
Configure your database connection string in appSettings.json.

That's all the configuration need to set up the SQL cache table and now run the application and check the session store in the cache table as follows.

Wrapping Up:

Hopefully, this article will help to understand the Session Management in .Net Core. I love to have your feedback, suggestions, and better techniques in the comment section.

Follow Me:

Comments

  1. Thank you. Helped me to understand how Session works in MVC Core.

    ReplyDelete
  2. how to make this session work on api with authenticate

    ReplyDelete
    Replies
    1. IN Web Api Core, Inject IHttpContextAccessor in your service constructor and use the session property. Other than that, the startup configurations are the same as above.

      Delete
  3. how to do admin login and update admin profile in dot net core

    ReplyDelete

Post a Comment

Popular posts from this blog

.NET6 Web API CRUD Operation With Entity Framework Core

In this article, we are going to do a small demo on AspNetCore 6 Web API CRUD operations. What Is Web API: Web API is a framework for building HTTP services that can be accessed from any client like browser, mobile devices, desktop apps. In simple terminology API(Application Programming Interface) means an interface module that contains a programming function that can be requested via HTTP calls to save or fetch the data for their respective clients. Some of the key characteristics of API: Supports HTTP verbs like 'GET', 'POST', 'PUT', 'DELETE', etc. Supports default responses like 'XML' and 'JSON'. Also can define custom responses. Supports self-hosting or individual hosting, so that all different kinds of apps can consume it. Authentication and Authorization are easy to implement. The ideal platform to build REST full services. Create A .NET6 Web API Application: Let's create a .Net6 Web API sample application to accomplish our

Usage Of CancellationToken In Asp.Net Core Applications

When To Use CancellationToken?: In a web application request abortion or orphan, requests are quite common. On users disconnected by network interruption or navigating between multiple pages before proper response or closing of the browser, tabs make the request aborted or orphan. An orphan request can't deliver a response to the client, but it will execute all steps(like database calls, HTTP calls, etc) at the server. Complete execution of an orphan request at the server might not be a problem generally if at all requests need to work on time taking a job at the server in those cases might be nice to terminate the execution immediately. So CancellationToken can be used to terminate a request execution at the server immediately once the request is aborted or orphan. Here we are going to see some sample code snippets about implementing a CancellationToken for Entity FrameworkCore, Dapper ORM, and HttpClient calls in Asp.NetCore MVC application. Note: The sample codes I will show in

A Small Guide On NestJS Queues

NestJS Application Queues helps to deal with application scaling and performance challenges. When To Use Queues?: API request that mostly involves in time taking operations like CPU bound operation, doing them synchronously which will result in thread blocking. So to avoid these issues, it is an appropriate way to make the CPU-bound operation separate background job.  In nestjs one of the best solutions for these kinds of tasks is to implement the Queues. For queueing mechanism in the nestjs application most recommended library is '@nestjs/bull'(Bull is nodejs queue library). The 'Bull' depends on Redis cache for data storage like a job. So in this queueing technique, we will create services like 'Producer' and 'Consumer'. The 'Producer' is used to push our jobs into the Redis stores. The consumer will read those jobs(eg: CPU Bound Operations) and process them. So by using this queues technique user requests processed very fastly because actually

Blazor WebAssembly Custom Authentication From Scratch

In this article, we are going to explore and implement custom authentication from the scratch. In this sample, we will use JWT authentication for user authentication. Main Building Blocks Of Blazor WebAssembly Authentication: The core concepts of blazor webassembly authentication are: AuthenticationStateProvider Service AuthorizeView Component Task<AuthenticationState> Cascading Property CascadingAuthenticationState Component AuthorizeRouteView Component AuthenticationStateProvider Service - this provider holds the authentication information about the login user. The 'GetAuthenticationStateAsync()' method in the Authentication state provider returns user AuthenticationState. The 'NotifyAuthenticationStateChaged()' to notify the latest user information within the components which using this AuthenticationStateProvider. AuthorizeView Component - displays different content depending on the user authorization state. This component uses the AuthenticationStateProvider

How Response Caching Works In Asp.Net Core

What Is Response Caching?: Response Caching means storing of response output and using stored response until it's under it's the expiration time. Response Caching approach cuts down some requests to the server and also reduces some workload on the server. Response Caching Headers: Response Caching carried out by the few Http based headers information between client and server. Main Response Caching Headers are like below Cache-Control Pragma Vary Cache-Control Header: Cache-Control header is the main header type for the response caching. Cache-Control will be decorated with the following directives. public - this directive indicates any cache may store the response. private - this directive allows to store response with respect to a single user and can't be stored with shared cache stores. max-age - this directive represents a time to hold a response in the cache. no-cache - this directive represents no storing of response and always fetch the fr

Part-1 Angular JWT Authentication Using HTTP Only Cookie[Angular V13]

In this article, we are going to implement a sample angular application authentication using HTTP only cookie that contains a JWT token. HTTP Only JWT Cookie: In a SPA(Single Page Application) Authentication JWT token either can be stored in browser 'LocalStorage' or in 'Cookie'. Storing JWT token inside of the cookie then the cookie should be HTTP Only. The HTTP-Only cookie nature is that it will be only accessible by the server application. Client apps like javascript-based apps can't access the HTTP-Only cookie. So if we use authentication with HTTP only JWT cookie then we no need to implement custom logic like adding authorization header or storing token data, etc at our client application. Because once the user authenticated cookie will be automatically sent to the server by the browser on every API call. Authentication API: To implement JWT cookie authentication we need to set up an API. For that, I had created a mock authentication API(Using the NestJS Se

Unit Testing Asp.NetCore Web API Using xUnit[.NET6]

In this article, we are going to write test cases to an Asp.NetCore Web API(.NET6) application using the xUnit. xUnit For .NET: The xUnit for .Net is a free, open-source, community-focused unit testing tool for .NET applications. By default .Net also provides a xUnit project template to implement test cases. Unit test cases build upon the 'AAA' formula that means 'Arrange', 'Act' and 'Assert' Arrange - Declaring variables, objects, instantiating mocks, etc. Act - Calling or invoking the method that needs to be tested. Assert - The assert ensures that code behaves as expected means yielding expected output. Create An API And Unit Test Projects: Let's create a .Net6 Web API and xUnit sample applications to accomplish our demo. We can use either Visual Studio 2022 or Visual Studio Code(using .NET CLI commands) to create any.Net6 application. For this demo, I'm using the 'Visual Studio Code'(using the .NET CLI command) editor. Create a fo

Different HttpClient Techniques To Consume API Calls In Minimal API[.NET6]

In this article, we are going to implement different HttpClient techniques to consume API calls in minimal API. The different HttpClient techniques that we are going to explore are like: Register HttpClient Object Explicitly In DI(Dependency Injection Service) Named Client Type Client HttpRequestMessage Object Create A .NET6 Minimal API Project: Let's create a .Net6 Minimal API sample project to accomplish our demo. We can use either Visual Studio 2022 or Visual Studio Code(using .NET CLI commands) to create any.Net6 application. For this demo, I'm using the 'Visual Studio Code'(using the .NET CLI command) editor. CLI command For Minimal API Project dotnet new webapi -minimal -o Your_Project_Name Create A Third Party API Response Model: Here I'm going to use a free third-party rest API that is "https://jsonplaceholder.typicode.com/posts". So to receive the response let's create a response model like 'Post.cs'. Program.cs:(Add Post.cs c

.Net5 Web API Managing Files Using Azure Blob Storage

In this article, we are going to understand the different file operations like uploading, reading, downloading, and deleting in .Net5 Web API application using Azure Blob Storage. Azure Blob Storage: Azure blob storage is Microsoft cloud storage. Blob storage can store a massive amount of file data as unstructured data. The unstructured data means not belong to any specific type, which means text or binary data. So something like images or pdf or videos to store in the cloud, then the most recommended is to use the blob store. The key component to creating azure blob storage resource: Storage Account:- A Storage account gives a unique namespace in Azure for all the data we will save. Every object that we store in Azure Storage has an address. The address is nothing but the unique name of our Storage Account name. The combination of the account name and the Azure Storage blob endpoint forms the base address for each object in our Storage account. For example, if our Storage Account is n

.Net5 Web API Redis Cache Using StackExchange.Redis.Extensions.AspNetCore Library

In this article, we are going to explore the integration of Redis cache in .Net5 Web API application using the 'StackExchange.Redis.Exntensions' library. Note:- Microsoft has introduced an 'IDistributedCache' interface in dotnet core which supports different cache stores like In-Memory, Redis, NCache, etc. It is simple and easy to work with  'IDistributedCache', for the Redis store with limited features but if we want more features of the Redis store we can choose to use 'StackExchange.Redis.Extensions'.  Click here for Redis Cache Integration Using IDistributedCache Interface . Overview On StackExchange.Redis.Extnesions Library: The 'StackExchange.Redis.Extension' library extended from the main library 'StackExchange.Redis'. Some of the key features of this library like: Default serialization and deserialization. Easy to save and fetch complex objects. Search key. Multiple Database Access Setup Redis Docker Instance: For this sampl