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Tutorial: Create a web API with ASP.NET Core

rick-anderson

Learn how to build a web API with ASP.NET Core.

riande

mvc

08/13/2020

Blazor

Blazor Server

Blazor WebAssembly

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Let's Encrypt

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tutorials/first-web-api

Tutorial: Create a web API with ASP.NET Core

By Rick Anderson, Kirk Larkin, and Mike Wasson

This tutorial teaches the basics of building a web API with ASP.NET Core.

::: moniker range=">= aspnetcore-3.0"

In this tutorial, you learn how to:

[!div class="checklist"]

Create a web API project.

Add a model class and a database context.

Scaffold a controller with CRUD methods.

Configure routing, URL paths, and return values.

Call the web API with Postman.

At the end, you have a web API that can manage "to-do" items stored in a database.

Overview

This tutorial creates the following API:

API	Description	Request body	Response body
`GET /api/TodoItems`	Get all to-do items	None	Array of to-do items
`GET /api/TodoItems/{id}`	Get an item by ID	None	To-do item
`POST /api/TodoItems`	Add a new item	To-do item	To-do item
`PUT /api/TodoItems/{id}`	Update an existing item	To-do item	None
`DELETE /api/TodoItems/{id}`	Delete an item	None	None

The following diagram shows the design of the app.

Prerequisites

Visual Studio

[!INCLUDE]

Visual Studio Code

[!INCLUDE]

Visual Studio for Mac

[!INCLUDE]

Create a web project

Visual Studio

From the File menu, select New > Project.
Select the ASP.NET Core Web Application template and click Next.
Name the project TodoApi and click Create.
In the Create a new ASP.NET Core Web Application dialog, confirm that .NET Core and ASP.NET Core 3.1 are selected. Select the API template and click Create.

Visual Studio Code

Open the integrated terminal.
Change directories (cd) to the folder that will contain the project folder.

Run the following commands:

dotnet new webapi -o TodoApi
cd TodoApi
dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package Microsoft.EntityFrameworkCore.InMemory
code -r ../TodoApi

When a dialog box asks if you want to add required assets to the project, select Yes.

The preceding commands:
- Creates a new web API project and opens it in Visual Studio Code.
- Adds the NuGet packages which are required in the next section.

Visual Studio for Mac

Select File > New Solution.
In Visual Studio for Mac earlier than version 8.6, select .NET Core > App > API > Next. In version 8.6 or later, select Web and Console > App > API > Next.
In the Configure the new ASP.NET Core Web API dialog, select the latest .NET Core 3.x Target Framework. Select Next.
Enter TodoApi for the Project Name and then select Create.

[!INCLUDE]

Open a command terminal in the project folder and run the following commands:

dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package Microsoft.EntityFrameworkCore.InMemory

Test the API

The project template creates a WeatherForecast API. Call the Get method from a browser to test the app.

Visual Studio

Press Ctrl+F5 to run the app. Visual Studio launches a browser and navigates to https://localhost:<port>/WeatherForecast, where <port> is a randomly chosen port number.

If you get a dialog box that asks if you should trust the IIS Express certificate, select Yes. In the Security Warning dialog that appears next, select Yes.

Visual Studio Code

Press Ctrl+F5 to run the app. In a browser, go to following URL: https://localhost:5001/WeatherForecast.

Visual Studio for Mac

Select Run > Start Debugging to launch the app. Visual Studio for Mac launches a browser and navigates to https://localhost:<port>, where <port> is a randomly chosen port number. An HTTP 404 (Not Found) error is returned. Append /WeatherForecast to the URL (change the URL to https://localhost:<port>/WeatherForecast).

JSON similar to the following is returned:

[
    {
        "date": "2019-07-16T19:04:05.7257911-06:00",
        "temperatureC": 52,
        "temperatureF": 125,
        "summary": "Mild"
    },
    {
        "date": "2019-07-17T19:04:05.7258461-06:00",
        "temperatureC": 36,
        "temperatureF": 96,
        "summary": "Warm"
    },
    {
        "date": "2019-07-18T19:04:05.7258467-06:00",
        "temperatureC": 39,
        "temperatureF": 102,
        "summary": "Cool"
    },
    {
        "date": "2019-07-19T19:04:05.7258471-06:00",
        "temperatureC": 10,
        "temperatureF": 49,
        "summary": "Bracing"
    },
    {
        "date": "2019-07-20T19:04:05.7258474-06:00",
        "temperatureC": -1,
        "temperatureF": 31,
        "summary": "Chilly"
    }
]

Add a model class

A model is a set of classes that represent the data that the app manages. The model for this app is a single TodoItem class.

Visual Studio

In Solution Explorer, right-click the project. Select Add > New Folder. Name the folder Models.
Right-click the Models folder and select Add > Class. Name the class TodoItem and select Add.
Replace the template code with the following code:

Visual Studio Code

Add a folder named Models.
Add a TodoItem class to the Models folder with the following code:

Visual Studio for Mac

Right-click the project. Select Add > New Folder. Name the folder Models.
Right-click the Models folder, and select Add > New File > General > Empty Class.
Name the class TodoItem, and then click New.
Replace the template code with the following code:

[!code-csharp]

The Id property functions as the unique key in a relational database.

Model classes can go anywhere in the project, but the Models folder is used by convention.

Add a database context

The database context is the main class that coordinates Entity Framework functionality for a data model. This class is created by deriving from the Microsoft.EntityFrameworkCore.DbContext class.

Visual Studio

Add NuGet packages

From the Tools menu, select NuGet Package Manager > Manage NuGet Packages for Solution.
Select the Browse tab, and then enter Microsoft.EntityFrameworkCore.SqlServer in the search box.
Select Microsoft.EntityFrameworkCore.SqlServer in the left pane.
Select the Project check box in the right pane and then select Install.
Use the preceding instructions to add the Microsoft.EntityFrameworkCore.InMemory NuGet package.

Add the TodoContext database context

Right-click the Models folder and select Add > Class. Name the class TodoContext and click Add.

Visual Studio Code / Visual Studio for Mac

Add a TodoContext class to the Models folder.

Enter the following code:

[!code-csharp]

Register the database context

In ASP.NET Core, services such as the DB context must be registered with the dependency injection (DI) container. The container provides the service to controllers.

Update Startup.cs with the following highlighted code:

[!code-csharp]

The preceding code:

Removes unused using declarations.
Adds the database context to the DI container.
Specifies that the database context will use an in-memory database.

Scaffold a controller

Visual Studio

Right-click the Controllers folder.
Select Add > New Scaffolded Item.
Select API Controller with actions, using Entity Framework, and then select Add.
In the Add API Controller with actions, using Entity Framework dialog:
- Select TodoItem (TodoApi.Models) in the Model class.
- Select TodoContext (TodoApi.Models) in the Data context class.
- Select Add.

Visual Studio Code / Visual Studio for Mac

Run the following commands:

dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design
dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet tool install --global dotnet-aspnet-codegenerator
dotnet tool update -g Dotnet-aspnet-codegenerator
dotnet-aspnet-codegenerator controller -name TodoItemsController -async -api -m TodoItem -dc TodoContext -outDir Controllers

The preceding commands:

Add NuGet packages required for scaffolding.
Installs the scaffolding engine (dotnet-aspnet-codegenerator).
Scaffolds the TodoItemsController.

The generated code:

Marks the class with the [ApiController] attribute. This attribute indicates that the controller responds to web API requests. For information about specific behaviors that the attribute enables, see xref:web-api/index.
Uses DI to inject the database context (TodoContext) into the controller. The database context is used in each of the CRUD methods in the controller.

The ASP.NET Core templates for:

Controllers with views include [action] in the route template.
API controllers don't include [action] in the route template.

When the [action] token isn't in the route template, the action name is excluded from the route. That is, the action's associated method name isn't used in the matching route.

Examine the PostTodoItem create method

Replace the return statement in the PostTodoItem to use the nameof operator:

[!code-csharp]

The preceding code is an HTTP POST method, as indicated by the [HttpPost] attribute. The method gets the value of the to-do item from the body of the HTTP request.

For more information, see Attribute routing with Http[Verb] attributes.

The xref:Microsoft.AspNetCore.Mvc.ControllerBase.CreatedAtAction* method:

Returns an HTTP 201 status code if successful. HTTP 201 is the standard response for an HTTP POST method that creates a new resource on the server.
Adds a Location header to the response. The Location header specifies the URI of the newly created to-do item. For more information, see 10.2.2 201 Created.
References the GetTodoItem action to create the Location header's URI. The C# nameof keyword is used to avoid hard-coding the action name in the CreatedAtAction call.

Install Postman

This tutorial uses Postman to test the web API.

Install Postman
Start the web app.
Start Postman.
Disable SSL certificate verification
- From File > Settings (General tab), disable SSL certificate verification.
  
  [!WARNING] Re-enable SSL certificate verification after testing the controller.

Test PostTodoItem with Postman

Create a new request.
Set the HTTP method to POST.
Set the URI to https://localhost:<port>/api/TodoItems. For example, https://localhost:5001/api/TodoItems.
Select the Body tab.
Select the raw radio button.
Set the type to JSON (application/json).

In the request body enter JSON for a to-do item:

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

Select Send.

Test the location header URI with Postman

Select the Headers tab in the Response pane.
Copy the Location header value:
Set the HTTP method to GET.
Set the URI to https://localhost:<port>/api/TodoItems/1. For example, https://localhost:5001/api/TodoItems/1.
Select Send.

Examine the GET methods

These methods implement two GET endpoints:

GET /api/TodoItems
GET /api/TodoItems/{id}

Test the app by calling the two endpoints from a browser or Postman. For example:

https://localhost:5001/api/TodoItems
https://localhost:5001/api/TodoItems/1

A response similar to the following is produced by the call to GetTodoItems:

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

Test Get with Postman

Create a new request.
Set the HTTP method to GET.
Set the request URI to https://localhost:<port>/api/TodoItems. For example, https://localhost:5001/api/TodoItems.
Set Two pane view in Postman.
Select Send.

This app uses an in-memory database. If the app is stopped and started, the preceding GET request will not return any data. If no data is returned, POST data to the app.

Routing and URL paths

The [HttpGet] attribute denotes a method that responds to an HTTP GET request. The URL path for each method is constructed as follows:

Start with the template string in the controller's Route attribute:

[!code-csharp]
Replace [controller] with the name of the controller, which by convention is the controller class name minus the "Controller" suffix. For this sample, the controller class name is TodoItemsController, so the controller name is "TodoItems". ASP.NET Core routing is case insensitive.
If the [HttpGet] attribute has a route template (for example, [HttpGet("products")]), append that to the path. This sample doesn't use a template. For more information, see Attribute routing with Http[Verb] attributes.

In the following GetTodoItem method, "{id}" is a placeholder variable for the unique identifier of the to-do item. When GetTodoItem is invoked, the value of "{id}" in the URL is provided to the method in its id parameter.

[!code-csharp]

Return values

The return type of the GetTodoItems and GetTodoItem methods is ActionResult<T> type. ASP.NET Core automatically serializes the object to JSON and writes the JSON into the body of the response message. The response code for this return type is 200, assuming there are no unhandled exceptions. Unhandled exceptions are translated into 5xx errors.

ActionResult return types can represent a wide range of HTTP status codes. For example, GetTodoItem can return two different status values:

If no item matches the requested ID, the method returns a 404 xref:Microsoft.AspNetCore.Mvc.ControllerBase.NotFound%2A error code.
Otherwise, the method returns 200 with a JSON response body. Returning item results in an HTTP 200 response.

The PutTodoItem method

Examine the PutTodoItem method:

[!code-csharp]

PutTodoItem is similar to PostTodoItem, except it uses HTTP PUT. The response is 204 (No Content). According to the HTTP specification, a PUT request requires the client to send the entire updated entity, not just the changes. To support partial updates, use HTTP PATCH.

If you get an error calling PutTodoItem, call GET to ensure there's an item in the database.

Test the PutTodoItem method

This sample uses an in-memory database that must be initialized each time the app is started. There must be an item in the database before you make a PUT call. Call GET to insure there's an item in the database before making a PUT call.

Update the to-do item that has ID = 1 and set its name to "feed fish":

  {
    "ID":1,
    "name":"feed fish",
    "isComplete":true
  }

The following image shows the Postman update:

The DeleteTodoItem method

Examine the DeleteTodoItem method:

[!code-csharp]

Test the DeleteTodoItem method

Use Postman to delete a to-do item:

Set the method to DELETE.
Set the URI of the object to delete (for example https://localhost:5001/api/TodoItems/1).
Select Send.

Prevent over-posting

Currently the sample app exposes the entire TodoItem object. Production apps typically limit the data that's input and returned using a subset of the model. There are multiple reasons behind this and security is a major one. The subset of a model is usually referred to as a Data Transfer Object (DTO), input model, or view model. DTO is used in this article.

A DTO may be used to:

Prevent over-posting.
Hide properties that clients are not supposed to view.
Omit some properties in order to reduce payload size.
Flatten object graphs that contain nested objects. Flattened object graphs can be more convenient for clients.

To demonstrate the DTO approach, update the TodoItem class to include a secret field:

[!code-csharp]

The secret field needs to be hidden from this app, but an administrative app could choose to expose it.

Verify you can post and get the secret field.

Create a DTO model:

[!code-csharp]

Update the TodoItemsController to use TodoItemDTO:

[!code-csharp]

Verify you can't post or get the secret field.

Call the web API with JavaScript

See Tutorial: Call an ASP.NET Core web API with JavaScript.

::: moniker-end

::: moniker range="< aspnetcore-3.0"

In this tutorial, you learn how to:

[!div class="checklist"]

Create a web API project.

Add a model class and a database context.

Add a controller.

Add CRUD methods.

Configure routing and URL paths.

Specify return values.

Call the web API with Postman.

Call the web API with JavaScript.

At the end, you have a web API that can manage "to-do" items stored in a relational database.

Overview

This tutorial creates the following API:

API	Description	Request body	Response body
GET /api/TodoItems	Get all to-do items	None	Array of to-do items
GET /api/TodoItems/{id}	Get an item by ID	None	To-do item
POST /api/TodoItems	Add a new item	To-do item	To-do item
PUT /api/TodoItems/{id}	Update an existing item	To-do item	None
DELETE /api/TodoItems/{id}	Delete an item	None	None

The following diagram shows the design of the app.

Prerequisites

Visual Studio

[!INCLUDE]

Visual Studio Code

[!INCLUDE]

Visual Studio for Mac

[!INCLUDE]

Create a web project

Visual Studio

From the File menu, select New > Project.
Select the ASP.NET Core Web Application template and click Next.
Name the project TodoApi and click Create.
In the Create a new ASP.NET Core Web Application dialog, confirm that .NET Core and ASP.NET Core 2.2 are selected. Select the API template and click Create. Don't select Enable Docker Support.

Visual Studio Code

Open the integrated terminal.
Change directories (cd) to the folder that will contain the project folder.
Run the following commands:
```
dotnet new webapi -o TodoApi
code -r TodoApi
```
These commands create a new web API project and open a new instance of Visual Studio Code in the new project folder.
When a dialog box asks if you want to add required assets to the project, select Yes.

Visual Studio for Mac

Select File > New Solution.
In Visual Studio for Mac earlier than version 8.6, select .NET Core > App > API > Next. In version 8.6 or later, select Web and Console > App > API > Next.
In the Configure the new ASP.NET Core Web API dialog, select the latest .NET Core 2.x Target Framework. Select Next.
Enter TodoApi for the Project Name and then select Create.

Test the API

The project template creates a values API. Call the Get method from a browser to test the app.

Visual Studio

Press Ctrl+F5 to run the app. Visual Studio launches a browser and navigates to https://localhost:<port>/api/values, where <port> is a randomly chosen port number.

If you get a dialog box that asks if you should trust the IIS Express certificate, select Yes. In the Security Warning dialog that appears next, select Yes.

Visual Studio Code

Press Ctrl+F5 to run the app. In a browser, go to following URL: https://localhost:5001/api/values.

Visual Studio for Mac

Select Run > Start Debugging to launch the app. Visual Studio for Mac launches a browser and navigates to https://localhost:<port>, where <port> is a randomly chosen port number. An HTTP 404 (Not Found) error is returned. Append /api/values to the URL (change the URL to https://localhost:<port>/api/values).

The following JSON is returned:

["value1","value2"]

Add a model class

A model is a set of classes that represent the data that the app manages. The model for this app is a single TodoItem class.

Visual Studio

In Solution Explorer, right-click the project. Select Add > New Folder. Name the folder Models.
Right-click the Models folder and select Add > Class. Name the class TodoItem and select Add.
Replace the template code with the following code:

Visual Studio Code

Add a folder named Models.
Add a TodoItem class to the Models folder with the following code:

Visual Studio for Mac

Right-click the project. Select Add > New Folder. Name the folder Models.
Right-click the Models folder, and select Add > New File > General > Empty Class.
Name the class TodoItem, and then click New.
Replace the template code with the following code:

[!code-csharp]

The Id property functions as the unique key in a relational database.

Model classes can go anywhere in the project, but the Models folder is used by convention.

Add a database context

The database context is the main class that coordinates Entity Framework functionality for a data model. This class is created by deriving from the Microsoft.EntityFrameworkCore.DbContext class.

Visual Studio

Right-click the Models folder and select Add > Class. Name the class TodoContext and click Add.

Visual Studio Code / Visual Studio for Mac

Add a TodoContext class to the Models folder.

Replace the template code with the following code:

[!code-csharp]

Register the database context

In ASP.NET Core, services such as the DB context must be registered with the dependency injection (DI) container. The container provides the service to controllers.

Update Startup.cs with the following highlighted code:

[!code-csharp]

The preceding code:

Removes unused using declarations.
Adds the database context to the DI container.
Specifies that the database context will use an in-memory database.

Add a controller

Visual Studio

Right-click the Controllers folder.
Select Add > New Item.
In the Add New Item dialog, select the API Controller Class template.
Name the class TodoController, and select Add.

Visual Studio Code / Visual Studio for Mac

In the Controllers folder, create a class named TodoController.

Replace the template code with the following code:

[!code-csharp]

The preceding code:

Defines an API controller class without methods.
Marks the class with the [ApiController] attribute. This attribute indicates that the controller responds to web API requests. For information about specific behaviors that the attribute enables, see xref:web-api/index.
Uses DI to inject the database context (TodoContext) into the controller. The database context is used in each of the CRUD methods in the controller.
Adds an item named Item1 to the database if the database is empty. This code is in the constructor, so it runs every time there's a new HTTP request. If you delete all items, the constructor creates Item1 again the next time an API method is called. So it may look like the deletion didn't work when it actually did work.

Add Get methods

To provide an API that retrieves to-do items, add the following methods to the TodoController class:

[!code-csharp]

These methods implement two GET endpoints:

GET /api/todo
GET /api/todo/{id}

Stop the app if it's still running. Then run it again to include the latest changes.

Test the app by calling the two endpoints from a browser. For example:

https://localhost:<port>/api/todo
https://localhost:<port>/api/todo/1

The following HTTP response is produced by the call to GetTodoItems:

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

Routing and URL paths

The [HttpGet] attribute denotes a method that responds to an HTTP GET request. The URL path for each method is constructed as follows:

Start with the template string in the controller's Route attribute:

[!code-csharp]
Replace [controller] with the name of the controller, which by convention is the controller class name minus the "Controller" suffix. For this sample, the controller class name is TodoController, so the controller name is "todo". ASP.NET Core routing is case insensitive.
If the [HttpGet] attribute has a route template (for example, [HttpGet("products")]), append that to the path. This sample doesn't use a template. For more information, see Attribute routing with Http[Verb] attributes.

[!code-csharp]

Return values

ActionResult return types can represent a wide range of HTTP status codes. For example, GetTodoItem can return two different status values:

If no item matches the requested ID, the method returns a 404 xref:Microsoft.AspNetCore.Mvc.ControllerBase.NotFound%2A error code.
Otherwise, the method returns 200 with a JSON response body. Returning item results in an HTTP 200 response.

Test the GetTodoItems method

This tutorial uses Postman to test the web API.

Install Postman.
Start the web app.
Start Postman.
Disable SSL certificate verification.

Visual Studio

From File > Settings (General tab), disable SSL certificate verification.

Visual Studio Code / Visual Studio for Mac

From Postman > Preferences (General tab), disable SSL certificate verification. Alternatively, select the wrench and select Settings, then disable the SSL certificate verification.

[!WARNING] Re-enable SSL certificate verification after testing the controller.

Create a new request.
- Set the HTTP method to GET.
- Set the request URI to https://localhost:<port>/api/todo. For example, https://localhost:5001/api/todo.
Set Two pane view in Postman.
Select Send.

Add a Create method

Add the following PostTodoItem method inside of Controllers/TodoController.cs:

[!code-csharp]

The preceding code is an HTTP POST method, as indicated by the [HttpPost] attribute. The method gets the value of the to-do item from the body of the HTTP request.

The CreatedAtAction method:

Returns an HTTP 201 status code, if successful. HTTP 201 is the standard response for an HTTP POST method that creates a new resource on the server.
Adds a Location header to the response. The Location header specifies the URI of the newly created to-do item. For more information, see 10.2.2 201 Created.
References the GetTodoItem action to create the Location header's URI. The C# nameof keyword is used to avoid hard-coding the action name in the CreatedAtAction call.

[!code-csharp]

Test the PostTodoItem method

Build the project.
In Postman, set the HTTP method to POST.
Set the URI to https://localhost:<port>/api/TodoItem. For example, https://localhost:5001/api/TodoItem.
Select the Body tab.
Select the raw radio button.
Set the type to JSON (application/json).

In the request body enter JSON for a to-do item:

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

Select Send.

If you get a 405 Method Not Allowed error, it's probably the result of not compiling the project after adding the PostTodoItem method.

Test the location header URI

Select the Headers tab in the Response pane.
Copy the Location header value:
Set the method to GET. * Set the URI to https://localhost:<port>/api/TodoItems/2. For example, https://localhost:5001/api/TodoItems/2.
Select Send.

Add a PutTodoItem method

Add the following PutTodoItem method:

[!code-csharp]

If you get an error calling PutTodoItem, call GET to ensure there's an item in the database.

Test the PutTodoItem method

Update the to-do item that has id = 1 and set its name to "feed fish":

  {
    "ID":1,
    "name":"feed fish",
    "isComplete":true
  }

The following image shows the Postman update:

Add a DeleteTodoItem method

Add the following DeleteTodoItem method:

[!code-csharp]

The DeleteTodoItem response is 204 (No Content).

Test the DeleteTodoItem method

Use Postman to delete a to-do item:

Set the method to DELETE.
Set the URI of the object to delete (for example, https://localhost:5001/api/todo/1).
Select Send.

The sample app allows you to delete all the items. However, when the last item is deleted, a new one is created by the model class constructor the next time the API is called.

Call the web API with JavaScript

In this section, an HTML page is added that uses JavaScript to call the web API. jQuery initiates the request. JavaScript updates the page with the details from the web API's response.

Configure the app to serve static files and enable default file mapping by updating Startup.cs with the following highlighted code:

[!code-csharp]

Create a wwwroot folder in the project directory.

Add an HTML file named index.html to the wwwroot directory. Replace its contents with the following markup:

[!code-html]

Add a JavaScript file named site.js to the wwwroot directory. Replace its contents with the following code:

[!code-javascript]

A change to the ASP.NET Core project's launch settings may be required to test the HTML page locally:

Open Properties\launchSettings.json.
Remove the launchUrl property to force the app to open at index.html—the project's default file.

This sample calls all of the CRUD methods of the web API. Following are explanations of the calls to the API.

Get a list of to-do items

jQuery sends an HTTP GET request to the web API, which returns JSON representing an array of to-do items. The success callback function is invoked if the request succeeds. In the callback, the DOM is updated with the to-do information.

[!code-javascript]

Add a to-do item

jQuery sends an HTTP POST request with the to-do item in the request body. The accepts and contentType options are set to application/json to specify the media type being received and sent. The to-do item is converted to JSON by using JSON.stringify. When the API returns a successful status code, the getData function is invoked to update the HTML table.

[!code-javascript]

Update a to-do item

Updating a to-do item is similar to adding one. The url changes to add the unique identifier of the item, and the type is PUT.

[!code-javascript]

Delete a to-do item

Deleting a to-do item is accomplished by setting the type on the AJAX call to DELETE and specifying the item's unique identifier in the URL.

[!code-javascript]

::: moniker-end

Add authentication support to a web API

[!INCLUDE]

Additional resources

View or download sample code for this tutorial. See how to download.

For more information, see the following resources:

40 KiB Raw Blame History

Tutorial: Create a web API with ASP.NET Core

Overview

Prerequisites

Create a web project

Test the API

Add a model class

Add a database context

Add NuGet packages

Add the TodoContext database context

Register the database context

Scaffold a controller

Examine the PostTodoItem create method

Install Postman

Test PostTodoItem with Postman

Test the location header URI with Postman

Examine the GET methods

Test Get with Postman

Routing and URL paths

Return values

The PutTodoItem method

Test the PutTodoItem method

The DeleteTodoItem method

Test the DeleteTodoItem method

Prevent over-posting

Call the web API with JavaScript

Overview

Prerequisites

Create a web project

Test the API

Add a model class

Add a database context

Register the database context

Add a controller

Add Get methods

Routing and URL paths

Return values

Test the GetTodoItems method

Add a Create method

Test the PostTodoItem method

Test the location header URI

Add a PutTodoItem method

Test the PutTodoItem method

Add a DeleteTodoItem method

Test the DeleteTodoItem method

Call the web API with JavaScript

Get a list of to-do items

Add a to-do item

Update a to-do item

Delete a to-do item

Add authentication support to a web API

Additional resources

40 KiB

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