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In this article, we are going to understand GraphQL Subscriptions in an angular application using the Apollo Angular Library. Graphql Subscription: GraphQL subscriptions are a way to push data from the server to the clients that listen to real-time messages or payload or data from the server. Subscriptions are similar to queries in that they specify a set of fields to be delivered to the client, but instead of immediately returning a single response, a result is sent every time a particular event happens on the server. So for this demo, I have created a GraphQL endpoint in .Net5. So I'm going to use that as my server. Publisher: Subscriber: So above 2 images like 'Publisher' and 'Subscriber' are tested using the browser. Now we will implement those publisher and subscriber functionalities into the angular application. Create An Angular Application: Let's begin our demo by creating an angular sample application. Command To Install Angular CLI:(If not insta

This article will implement a small demo on subscriptions in Hot Chocolate Graphql using the application In-Memory storage. Since our target storage is application In-Memory, so this approach only apt for a single server hosted application. For applications with multiple servers then we have to use Redis Store. GraphQL Subscription Flow: In general, events raising or publishing will be triggered from the GraphQL mutation resolvers. Inside mutation resolvers raise the event to store the data into application in-memory storage. In GraphQL 'Subscriptions' is one of the root definitions like 'Query', Mutation'. So the subscription resolvers will always receive the data from in-memory storage. So the subscription resolvers can also be called subscribers whose job always watches the data send by the raised events. So the event raised from the mutation resolver will be received by all subscribers. Create A .Net5 Web API App: Now let's begin our journey by creat

Part3  we had enabled the JWT token validation and discussed different authorization techniques as well. In this article, we will understand Refresh Token creation and its usage. When To Use Refresh Token: A refresh token is a unique random encrypted string. On the expiration of the JWT auth access token, instead of showing a login page to the user, we can make the user authenticated immediately using the refresh token. By using refresh token we can fetch new user access tokens from the server without any user credentials. Generate Refresh Token: In 'AuthLogic.cs' file add a new private method like 'GenerateRefreshToken()'. Logics/AuthLogics.cs: private string GenerateRefreshToken() { var randomNumber = new byte[32]; using (var generator = RandomNumberGenerator.Create()) { generator.GetBytes(randomNumber); return Convert.ToBase64String(randomNumber); } } Here using 'System.Security.Cryptography.RandomNumberGenerator' generated refresh token of leng

Part2  we had generated a JWT access token for the user authentication. In this article, we are going to validate the JWT access token and also understand different techniques of Authorization. Install JwtBearer NuGet: To enable jwt token validation service we have to install JwtBearer NuGet. Package Manager Command: Install-Package Microsoft.AspNetCore.Authentication.JwtBearer -Version 5.0.4 .Net CLI Command: dotnet add package Microsoft.AspNetCore.Authentication.JwtBearer --version 5.0.4 Register JwtBearer Service: In the 'Startup.cs' file, we should register our JwtBearer validation service. Startup.cs: services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme) .AddJwtBearer(options => { var tokenSettings = Configuration .GetSection("TokenSettings").Get<TokenSettings>(); options.TokenValidationParameters = new TokenValidationParameters { ValidIssuer = tokenSettings.Issuer, ValidateIssuer = true, ValidAudience = tokenSettings.Audienc

Part1  discussed user registration. In this article, we are going to implement logic to generate the JWT access token in the Hot Chocolate GraphQL. Overview On JWT(JSON Web Token): JSON Web Token is a digitally signed and secured token for user validation. The jwt is constructed with 3 informative parts: Header Payload Signature Install JWT NuGet: Package Manager Command: Install-Package System.IdentityModel.Tokens.Jwt -Version 6.9.0 .Net CLI Command: dotnet add package System.IdentityModel.Tokens.Jwt --version 6.9.0 Add Token Settings: While generating the JWT access token, few token-specific settings need to be specified. appsettings.Development.json: "TokenSettings":{ "Issuer":"localhost:5001", "Audience":"js.app.com", "Key":"SomeRandomlyGeneratedStringSomeRandomlyGeneratedString" } The 'Issuer' is like the identification of the server that generated the token. In access token 'iss'

About The Series: Using Pure Code First Technique In Hot Chocolate GraphQL, Custom Authentication Series: Part1 User Registration Resolver Part2 Generating JWT Access Token For User Authentication. Part3 Validating JWT Access Token And Different Authorization Techniques Part4 Generating Refresh Token. So this our Part-1 of the series where we are going to create a sample in GraphQL for user registration. SQL Tables: Create 2 tables like 'User' and 'UserRoles'. User Table: CREATE TABLE [dbo].[User]( [UserId] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](192) NULL, [LastName] [varchar](192) NULL, [EmailAddress] [varchar](192) NOT NULL, [Password] [varchar](640) NOT NULL, [RefreshToken] [varchar](640) NULL, [RefershTokenExpiration] [datetime] NULL, CONSTRAINT [PK_User] PRIMARY KEY CLUSTERED ( [UserId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY