ASP.NET Core Web API - Build an API from Scratch

Explore the basics of web api requests, client–server workflow, and common api operations. Review http status codes and the CMS Open API specification for a college management system.

Explore the client–server request workflow of a web API, including a get /courses call processed by a database repository, returning 200 ok or 500 internal server error.

Create a new asp.net core web api project with dotnet new web api in a vscode workspace, run on port 5000, and test the weather forecast endpoint with Postman.

Understand how a web API in ASP.NET Core wires its host, services, middleware, and routing from Program.cs and Startup.cs, enabling controllers and swagger by default.

Explore the http request-response cycle and core web api operations (get, post, put, delete, patch) along with common status codes for success and errors in a college management system project.

Learn how asp.net core web api controllers derive from the controller base class to handle http requests, and how api controller attributes enable attribute routing, binding, and automatic 400 responses.

Build a collection API with ASP.NET Core. Create a web API project, add a controller with actions, model data, wire a database repository, and implement a get all items operation.

Delete the weather forecast controller and create a new courses controller derived from the controller base class, adding a constructor for dependency injection plus the controller and route attribute.

Add http get, http post, http put, and http delete actions to the controller to fetch resources like a courses list, and test the endpoint with Postman.

Implement the get all courses operation in an in-memory CMS repository using a DTO mapping strategy, exposing via ASP.NET Core Web API and validating with Postman on port 5000.

Build an ASP.NET Core web API by creating a controller with routing, define actions with HTTP verbs, inject repositories (including in-memory), and map data models to DTOs to fetch courses.

Use IActionResult in ASP.NET Core to return multiple results, such as okay object result and bad request, and handle exceptions with status 500 while testing via Postman.

Use action result of T to return any type, with implicit cast handled by ASP.NET; for enumerables, return a list of T to support status codes, including internal server error.

Learn to implement asynchronous programming in ASP.NET Core Web API using async and await for get operations, returning results with async task and async enumerable.

Implement get operation to fetch a course by id via http get route, validate existence, retrieve a course from the repository, map to the course model, and test with postman.

Implement put operation to update an existing course by reusing get logic, mapping with auto mapper, and updating the repository, then test with postman to verify changes.

Implement the delete operation for an individual course by using an http delete endpoint that accepts a course ID, validates existence, and removes the item from the in-memory CMS repository.

Implement get, put, and delete operations for an individual item using http get with route parameters and simple Linq queries. This section completes the item APIs and previews association APIs.

Explore association APIs in a web API by exposing collection endpoints tied to items, using get and post to fetch related data like students in a course, with delete optional.

Explore the importance of versioning your web API and how to add versions to controllers and actions in an ASP.NET Core project.

Add versions to actions within a controller by duplicating actions and mapping them to specific API versions, such as 3.0, 2.0, or 1.0.

Learn how to implement multiple versioning strategies in a single API using a combined API version reader, supporting both query string and header versioning; ensure consistent versions for reliable requests.