AspNetCore.Docs/aspnetcore/tutorials/first-web-api-mac.md

title	author	description	helpviewer_heywords	manager	ms.author	ms.date	ms.prod	ms.technology	ms.topic	uid
Create a Web API with ASP.NET Core and Visual Studio for Mac	rick-anderson	Create a Web API with ASP.NET Core MVC and Visual Studio for Mac	ASP.NET Core, WebAPI, Web API, REST, mac, macOS, HTTP, Service, HTTP Service	wpickett	riande	09/15/2017	asp.net-core	aspnet	get-started-article	tutorials/first-web-api-mac

Create a Web API with ASP.NET Core MVC and Visual Studio for Mac

By Rick Anderson and Mike Wasson

In this tutorial, build a web API for managing a list of "to-do" items. The UI isn't constructed.

There are 3 versions of this tutorial:

• macOS: Web API with Visual Studio for Mac (This tutorial)
• Windows: Web API with Visual Studio for Windows
• macOS, Linux, Windows: Web API with Visual Studio Code

[!INCLUDEtemplate files]

• See Introduction to ASP.NET Core MVC on Mac or Linux for an example that uses a persistent database.

Prerequisites

Install the following:

• .NET Core 2.0.0 SDK or later
• Visual Studio for Mac

Create the project

From Visual Studio, select File > New Solution.

Select .NET Core App > ASP.NET Core Web API > Next.

Enter TodoApi for the Project Name, and then select Create.

Launch the app

In Visual Studio, select Run > Start With Debugging to launch the app. Visual Studio launches a browser and navigates to http://localhost:5000. You get an HTTP 404 (Not Found) error. Change the URL to http://localhost:port/api/values. The ValuesController data will be displayed:

["value1","value2"]

Add support for Entity Framework Core

Install the Entity Framework Core InMemory database provider. This database provider allows Entity Framework Core to be used with an in-memory database.

• From the Project menu, select Add NuGet Packages.

  • Alternately, you can right-click Dependencies, and then select Add Packages.

• Enter EntityFrameworkCore.InMemory in the search box.

• Select Microsoft.EntityFrameworkCore.InMemory, and then select Add Package.

Add a model class

A model is an object that represents the data in your application. In this case, the only model is a to-do item.

Add a folder named Models. In Solution Explorer, right-click the project. Select Add > New Folder. Name the folder Models.

Note: You can put model classes anywhere in your project, but the Models folder is used by convention.

Add a TodoItem class. Right-click the Models folder and select Add > New File > General > Empty Class. Name the class TodoItem, and then select New.

Replace the generated code with:

[!code-csharpMain]

The database generates the Id when a TodoItem is created.

Create the database context

The database context is the main class that coordinates Entity Framework functionality for a given data model. You create this class by deriving from the Microsoft.EntityFrameworkCore.DbContext class.

Add a TodoContext class to the Models folder.

[!code-csharpMain]

[!INCLUDERegister the database context]

Add a controller

In Solution Explorer, in the Controllers folder, add the class TodoController.

Replace the generated code with the following (and add closing braces):

[!INCLUDEcode and get todo items]

Launch the app

In Visual Studio, select Run > Start With Debugging to launch the app. Visual Studio launches a browser and navigates to http://localhost:port, where port is a randomly chosen port number. You get an HTTP 404 (Not Found) error. Change the URL to http://localhost:port/api/values. The ValuesController data will be displayed:

["value1","value2"]

Navigate to the Todo controller athttp://localhost:port/api/todo:

[{"key":1,"name":"Item1","isComplete":false}]

Implement the other CRUD operations

We'll add Create, Update, and Delete methods to the controller. These are variations on a theme, so I'll just show the code and highlight the main differences. Build the project after adding or changing code.

Create

[!code-csharpMain]

This is an HTTP POST method, indicated by the [HttpPost] attribute. The [FromBody] attribute tells MVC to get the value of the to-do item from the body of the HTTP request.

The CreatedAtRoute method returns a 201 response, which is the standard response for an HTTP POST method that creates a new resource on the server. CreatedAtRoute also adds a Location header to the response. The Location header specifies the URI of the newly created to-do item. See 10.2.2 201 Created.

Use Postman to send a Create request

• Start the app (Run > Start With Debugging).
• Start Postman.

• Set the HTTP method to POST
• Select the Body radio button
• Select the raw radio button
• Set the type to JSON
• In the key-value editor, enter a Todo item such as

{
	"name":"walk dog",
	"isComplete":true
}

• Select Send

• Select the Headers tab in the lower pane and copy the Location header:

You can use the Location header URI to access the resource you just created. Recall the GetById method created the "GetTodo" named route:

[HttpGet("{id}", Name = "GetTodo")]
public IActionResult GetById(string id)

Update

[!code-csharpMain]

Update is similar to Create, but uses HTTP PUT. The response is 204 (No Content). According to the HTTP spec, a PUT request requires the client to send the entire updated entity, not just the deltas. To support partial updates, use HTTP PATCH.

{
  "key": 1,
  "name": "walk dog",
  "isComplete": true
}

Delete

[!code-csharpMain]

The response is 204 (No Content).

Next steps

• Routing to Controller Actions
• For information about deploying your API, see Host and deploy.
• View or download sample code (how to download)
• Postman
• Fiddler