Using asp Net core creating web API series

Use ASP.NET Core establish Web API

This time mainly introduces the use of ASP.NET Core structure Web API Basic knowledge of .

In this tutorial , You will understand ：

• establish Web API project .
• Add model classes and database context .
• Use CRUD Method to build the controller .
• Configure the routing 、URL Path and return value .
• Use Postman call Web API.

summary This tutorial will create the following API：

API	explain	Request body	Response Content
GET /api/TodoItems	Get all the to-do items	nothing	An array of to-do items
GET /api/TodoItems/{id}	Press ID To obtain a	nothing	To do list
POST /api/TodoItems	Add a new item	To do list	To do list
PUT /api/TodoItems/{id}	Update existing items	To do list	nothing
DELETE /api/TodoItems/{id}	Delete the item	nothing	nothing

establish Web project

from “ file ” From the menu “ newly build ”>“ project ” .

choice “ASP.NET Core Web Applications ” Templates , Click again “ next step ” .

Name the project TodoApi, And then click “ establish ” .

stay “ Create a new ASP.NET Core Web Applications ” In the dialog box , Confirm selection “.NET Core” and “ASP.NET Core 3.1” .  choice “API” Templates , And then click “ establish ” .

 

Add model class

Model Is a group of classes that represent application management data .  The model for this application is a single  TodoItem  class .

1. stay “ Solution explorer ” in , Right click on the item .  choice “ add to ” > “ New folder ” .  Name the folder “Models” .
2. Right click “Models” Folder , And then choose “ add to ” > “ class ” .  Name the class TodoItem, And then choose “ add to ” .
3. Replace the template code with the following code ：

Build controller

• Right click Controllers Folder .
• choice “ add to ”>“ New build item ” .
• choice “ Its operation uses Entity Framework API controller ”, And then choose “ add to ” 

Check PostTodoItem create Method

Replace  PostTodoItem  The return statement in , To use the  nameof  Operator ：

 [Route("api/posttodoitem")]
    [ApiController]
    public class PostTodoItemController : ControllerBase
    {
        public static List<TodoItem> todoItems = new List<TodoItem>() {
            new TodoItem{Id=1,IsComplete=true,Name=" Zhang Yi Xing " },
            new TodoItem{Id=2,IsComplete=true,Name=" Zheng Kai " },
            new TodoItem{Id=3,IsComplete=true,Name=" Angela Baby " },
            new TodoItem{Id=4,IsComplete=true,Name=" Chen He " },
            new TodoItem{Id=5,IsComplete=true,Name=" Li Chen " },
        };

       [HttpPost]
        public async Task<ActionResult<TodoItem>> PostTodoItem(TodoItem todoItem)
        {

            todoItems.Add(todoItem);

            return CreatedAtAction(nameof(GetTodoItem), new { id = todoItem.Id }, todoItem);
           // return CreatedAtAction("GetTodoItem", new { id = todoItem.Id }, todoItem);
           
        }
        [HttpGet]
        public async Task<ActionResult<List<TodoItem>>> TodoItems()
        {



            return  await Task.Run(() => todoItems);
            // return CreatedAtAction("GetTodoItem", new { id = todoItem.Id }, todoItem);

        }

        [HttpGet("{id}")]
        public async Task<ActionResult<TodoItem>>GetTodoItem(int id)
        {

            var todoItem = await Task.Run(() => todoItems.Where(x => x.Id == id)); ;

            if (todoItem == null)
            {
                return NotFound();
            }

            return todoItem.FirstOrDefault();

        }
    }

install Postman

This tutorial USES Postman test Web API.

• install  Postman
• start-up Web application \( At testing time , It can be found in the project folder , function   cmd  
• Input ：dotnet  watch  run )

For example, the project location is ：

open Cmd

 

• start-up Postman.
• Ban  SSL Certificate validation
• stay “ file ”>“ Set up ”（“ routine ” tab ） in , Ban “SSL Certificate validation ” 

adopt Postman test PostTodoItem

• Create a new request .
• take HTTP Method set to  POST.
• choice “ Text ” tab .
• choice “ original ” Radio button .
• Set type to  JSON (application/json)
• In the body of the request , Enter the to-do list JSON：

{

Id:5

  "name":"walk dog",

  "isComplete":true

}

choice Send.

 

Test location header URI

• stay Headers  Select... In the pane Response  tab .
• Copy Location  Header value ：
• 

 

• Set the method to “GET”.
• Paste URI（ for example ,http://localhost:52655/api/posttodoitem/6）.
• choice Send.