Technology Wonders

In this article, we will go through the steps for creating ASP.NET Core API. We use API aka REST  APIs for creating data communication services. In short, we can say that we are building a service that can be consumed (or subscribed to) by any client application e.g.  JAVA, .NET, JavaScript Clients (like React, Angular, and Vue.js) so that these applications can make HTTP Requests and perform Data communication in JSON form. We can say the APIs can establish a data communication bridge between homogeneous or heterogeneous applications.    The ASP.NET Core is a complete eco-system that provides a single HTTP Pipeline for the following applications ASP.NET Core Razor Application ASP.NET Core MVC Application ASP.NET Core  Web API Application In this step-by-step post, we will use Visual Studio 2022 for creating the ASP.NET Core API project and SQL Server 2018 for the database.  The database scripts are provided in Listing 1. Create Database Company GO CREATE TABLE [dbo].[Department]( [

The minimal APIs in ASP.NET Core 7 is one of the best features. I have already written a post on the minimal APIs. In this article, I will demonstrate an approach to uploading files using minimal APIs. I have already written a post on file upload using ASP.NET Core on this link .   Step 1: Open Visual Studio 2022 and create a new ASP.NET Core API project targeted to .NET 7. Name this project  Core7_FIleUpload_MinimalAPI. You need to make sure that, the checkbox Use controllers (uncheck to use minimal APIs) is unchecked as shown in Figure 1. Once we uncheck this checkbox, then we will not see the  Controllers folder in our project. We need to write the API login in Program.cs. In this project add a new folder and name it files. All uploaded files will be stored in this folder.  Step 2: In the Program.cs, we will create two APIs one each for uploading a single file and uploading multiple files. To upload a single file we use the IFromFile interface. This interface represents a file sent

In this article, we will see using the PostgreSQL database to store the ASP.NET Identity information in it. If the ASP.NET Core application is using PostgreSQL database instead of SQL Server database then we can use it to store application user and role information. This article is a simple implementation of identity in ASP.NET Core using PostgreSQL. To create a database and tables for storing ASP.NET Identity information, we use classes like IdentityUser, IdentityRole, etc. The EntityFrameworkCore Code-First approach is used to create a database and tables.  Step 1: Open Visual Studio 2022 and create a new ASP.NET Core API project. Name this project as Core_API_Postgre_Identity. To use Identity classes and PostgreSQL add the following packages to the project Microsoft.AspNetCore.Identity This package is needed to use IdentityUser and IdentityRole classes Microsoft.AspNetCore.Identity.EntityFrameworkCore This package is needed to use IdentityDbContext class. This class is used as a bas

This article is an extension of my previous article . In the previous article, we have seen how to make parallel HTTP calls with RxJS forkJoin() method. In this article, we will use the combineLatest() operator of the RXJS. We use the combineLatest() operator when we need to call multiple APIs and combine them for some processing before returning the result. The best use of this operator is when you have multiple, long-lived observables that rely on each other for some calculation or determination. The use case is that the Angular application wants to access product information of different categories from various REST APIs but the Angular Application wants to show all products of received categories on UI by combining them. Figure 1 explains the use case. Figure 1: Using the combineLatest The combineLatest() operator accepts Observables by accessing REST APIs, and then further allows us to add the code to process these observables as per our requirements in the Angular client applicat

In this article, we will see the mechanism for accessing external REST APIs by making parallel calls using RxJs.  Angular, being the great framework for building complex front-end apps, various times we need to make HTTP calls to REST APIs to fetch data to show on UI. Of course, Angular provides HttpClientModule and HttpClient classes to manage asynchronous HTTP calls. The HttpClient provides get(), post(), put(), and delete() methods to perform HTTP operations and all these methods return an Observable object.  Objeservable is the most basic building block provided in RxJs. An Observable represents a set of values received over any time, this means that when the HTTP call returns data from REST API it is immediately delivered to UI so that the UI can be updated.  There is one more use case that must be considered which makes parallel HTTP calls to REST APIs to fetch data. Here, the challenge is how to collect these multiple observables at a time and pass them to UI? Figure 1 shows the