Self-Host ASP.NET Web API 1 (C#)

秒速五厘米 2022-07-15 01:28 158阅读 0赞

# Self-Host ASP.NET Web API 1 (C\#) #

By [ Mike Wasson][Mike Wasson] Mike Wasson |January 26, 2012

213 of 239 people found this helpful

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ASP.NET Web API does not require IIS. You can self-host a web API in your own host process. This tutorial shows how to host a web API inside a console application.

**New applications should use OWIN to self-host Web API.** See [ Use OWIN to Self-Host ASP.NET Web API 2][Use OWIN to Self-Host ASP.NET Web API 2].

## Software versions used in the tutorial ##

*  Web API 1
 *  Visual Studio 2012

## Create the Console Application Project ##

Start Visual Studio and select **New Project** from the **Start** page. Or, from the **File** menu, select **New** and then **Project**.

In the **Templates** pane, select **Installed Templates** and expand the **Visual C\#** node. Under **Visual C\#**, select  **Windows**. In the list of project templates, select **Console Application**. Name the project "SelfHost" and click **OK**.

![webapi_selfhost01.png][]

## Set the Target Framework (Visual Studio 2010) ##

If you are using Visual Studio 2010, change the target framework to .NET Framework 4.0. (By default, the project template targets the [ .Net Framework Client Profile][.Net Framework Client Profile].)

In Solution Explorer, right-click the project and select **Properties**. In the **Target framework** dropdown list, change the target framework to .NET Framework 4.0. When prompted to apply the change, click **Yes**.

![webapi_selfhost02.png][]

## Install NuGet Package Manager ##

The NuGet Package Manager is the easiest way to add the Web API assemblies to a non-ASP.NET project.

To check if NuGet Package Manager is installed, click the **Tools** menu in Visual Studio. If you see a menu item called **Library Package Manager**, then you have NuGet Package Manager.

To install NuGet Package Manager:

1.  Start Visual Studio.
2.  From the **Tools** menu, select **Extensions and Updates**.
3.  In the **Extensions and Updates** dialog, select **Online**.
4.  If you don't see "NuGet Package Manager", type "nuget package manager" in the search box.
5.  Select the NuGet Package Manager and click **Download**.
6.  After the download completes, you will be prompted to install.
7.  After the installation completes, you might be prompted to restart Visual Studio.

![webapi_selfhost03.png][]

## Add the Web API NuGet Package ##

After NuGet Package Manager is installed, add the Web API Self-Host package to your project.

1.  From the **Tools** menu, select **Library Package Manager**. *Note*: If do you not see this menu item, make sure that NuGet Package Manager installed correctly.
2.  Select **Manage NuGet Packages for Solution...**
3.  In the **Manage NugGet Packages** dialog, select **Online**.
4.  In the search box, type "Microsoft.AspNet.WebApi.SelfHost".
5.  Select the ASP.NET Web API Self Host package and click **Install**.
6.  After the package installs, click **Close** to close the dialog.

Make sure to install the package named Microsoft.AspNet.WebApi.SelfHost, not AspNetWebApi.SelfHost.

![webapi_selfhost04.png][]

## Create the Model and Controller ##

This tutorial uses the same model and controller classes as the [ Getting Started][Getting Started] tutorial.

Add a public class named `Product`.

namespace SelfHost
    {
       
        public class Product
        {
       
            public int Id {
        get; set; }
            public string Name {
        get; set; }
            public string Category {
        get; set; }
            public decimal Price {
        get; set; }
        }
    }

Add a public class named `ProductsController`. Derive this class from **System.Web.Http.ApiController**.

namespace SelfHost
    {
       
        using System;
        using System.Collections.Generic;
        using System.Linq;
        using System.Net;
        using System.Web.Http;
        
        public class ProductsController : ApiController
        {
       
            Product[] products = new Product[]  
            {
         
                new Product {
        Id = 1, Name = "Tomato Soup", Category = "Groceries", Price = 1 },  
                new Product {
        Id = 2, Name = "Yo-yo", Category = "Toys", Price = 3.75M },  
                new Product {
        Id = 3, Name = "Hammer", Category = "Hardware", Price = 16.99M }  
            };
    
            public IEnumerable<Product> GetAllProducts()
            {
       
                return products;
            }
    
            public Product GetProductById(int id)
            {
       
                var product = products.FirstOrDefault((p) => p.Id == id);
                if (product == null)
                {
       
                    throw new HttpResponseException(HttpStatusCode.NotFound);
                }
                return product;
            }
    
            public IEnumerable<Product> GetProductsByCategory(string category)
            {
       
                return products.Where(p => string.Equals(p.Category, category,
                        StringComparison.OrdinalIgnoreCase));
            }
        }
    }

For more information about the code in this controller, see the [ Getting Started][Getting Started] tutorial. This controller defines three GET actions:

<table> 
 <thead> 
  <tr> 
   <th>URI</th> 
   <th>Description</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>/api/products</td> 
   <td>Get a list of all products.</td> 
  </tr> 
  <tr> 
   <td>/api/products/<em>id</em></td> 
   <td>Get a product by ID.</td> 
  </tr> 
  <tr> 
   <td>/api/products/?category=<em>category</em></td> 
   <td>Get a list of products by category.</td> 
  </tr> 
 </tbody> 
</table>

## Host the Web API ##

Open the file Program.cs and add the following using statements:

using System.Web.Http;
    using System.Web.Http.SelfHost;

Add the following code to the **Program** class.

## (Optional) Add an HTTP URL Namespace Reservation ##

This application listens to http://localhost:8080/. By default, listening at a particular HTTP address requires administrator privileges. When you run the tutorial, therefore, you may get this error: "HTTP could not register URL http://+:8080/" There are two ways to avoid this error:

*  Run Visual Studio with elevated administrator permissions, or
 *  Use Netsh.exe to give your account permissions to reserve the URL.

To use Netsh.exe, open a command prompt with administrator privileges and enter the following command:following command:

netsh http add urlacl url=http://+:8080/ user=machine\username

where *machine\\username* is your user account.

When you are finished self-hosting, be sure to delete the reservation:

netsh http delete urlacl url=http://+:8080/

## Call the Web API from a Client Application (C\#) ##

Let's write a simple console application that calls the web API.

Add a new console application project to the solution:

*  In Solution Explorer, right-click the solution and select **Add New Project**.
 *  Create a new console application named "ClientApp".

![webapi_selfhost05.png][]

Use NuGet Package Manager to add the ASP.NET Web API Core Libraries package:

*  From the Tools menu, select **Library Package Manager**.
 *  Select **Manage NuGet Packages for Solution...**
 *  In the **Manage NuGet Packages** dialog, select **Online**.
 *  In the search box, type "Microsoft.AspNet.WebApi.Client".
 *  Select the Microsoft ASP.NET Web API Client Libraries package and click  **Install**.

Add a reference in ClientApp to the SelfHost project:

*  In Solution Explorer, right-click the ClientApp project.
 *  Select **Add Reference**.
 *  In the **Reference Manager** dialog, under **Solution**, select **Projects**.
 *  Select the SelfHost project.
 *  Click **OK**.

![webapi_selfhost06.png][]

Open the Client/Program.cs file. Add the following **using** statement:

using System.Net.Http;

Add a static **HttpClient** instance:

namespace Client
    {
       
        class Program
        {
       
            static HttpClient client = new HttpClient();
        }
    }

Add the following methods to list all products, list a product by ID, and list products by category.

static void ListAllProducts()
    {
       
        HttpResponseMessage resp = client.GetAsync("api/products").Result;
        resp.EnsureSuccessStatusCode();
    
        var products = resp.Content.ReadAsAsync<IEnumerable<SelfHost.Product>>().Result;
        foreach (var p in products)
        {
       
            Console.WriteLine("{0} {1} {2} ({3})", p.Id, p.Name, p.Price, p.Category);
        }
    }
    
    static void ListProduct(int id)
    {
       
        var resp = client.GetAsync(string.Format("api/products/{0}", id)).Result;
        resp.EnsureSuccessStatusCode();
    
        var product = resp.Content.ReadAsAsync<SelfHost.Product>().Result;
        Console.WriteLine("ID {0}: {1}", id, product.Name);
    }
    
    static void ListProducts(string category)
    {
       
        Console.WriteLine("Products in '{0}':", category);
    
        string query = string.Format("api/products?category={0}", category);
    
        var resp = client.GetAsync(query).Result;
        resp.EnsureSuccessStatusCode();
    
        var products = resp.Content.ReadAsAsync<IEnumerable<SelfHost.Product>>().Result;
        foreach (var product in products)
        {
       
            Console.WriteLine(product.Name);
        }
    }

Each of these methods follows the same pattern:

1.  Call **HttpClient.GetAsync** to send a GET request to the appropriate URI.
2.  Call **HttpResponseMessage.EnsureSuccessStatusCode**. This method throws an exception if the HTTP response status is an error code.
3.  Call **ReadAsAsync<T>** to deserialize a CLR type from the HTTP response. This method is an extension method, defined in **System.Net.Http.HttpContentExtensions**.

The **GetAsync** and **ReadAsAsync** methods are both asynchronous. They return **Task** objects that represent the asynchronous operation. Getting the **Result** property blocks the thread until the operation completes.

For more information about using HttpClient, including how to make non-blocking calls, see [ Calling a Web API From a .NET Client][Calling a Web API From a .NET Client].

Before calling these methods, set the BaseAddress property on the HttpClient instance to "http://localhost:8080". For example:

static void Main(string[] args)
    {
       
        client.BaseAddress = new Uri("http://localhost:8080");
    
        ListAllProducts();
        ListProduct(1);
        ListProducts("toys");
    
        Console.WriteLine("Press Enter to quit.");
        Console.ReadLine();
    }

This should output the following. (Remember to run the SelfHost application first.)

1 Tomato Soup 1.0 (Groceries)
    2 Yo-yo 3.75 (Toys)
    3 Hammer 16.99 (Hardware)
    ID 1: Tomato Soup
    Products in 'toys':
    Yo-yo
    Press Enter to quit.

![webapi_selfhost07.png][]

This article was originally created on January 26, 2012

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## Author Information ##

![Mike Wasson][Mike Wasson 1]

**Mike Wasson** – Mike Wasson is a programmer-writer at Microsoft.

[Mike Wasson]: https://www.asp.net/web-api/overview/older-versions/self-host-a-web-api#author-36870
[Tweet]: https://twitter.com/share
[Use OWIN to Self-Host ASP.NET Web API 2]: https://www.asp.net/web-api/overview/hosting-aspnet-web-api/use-owin-to-self-host-web-api
[webapi_selfhost01.png]: /images/20220715/12ee957314c04e469c1e84c0a8c12af1.png
[.Net Framework Client Profile]: http://msdn.microsoft.com/en-us/library/cc656912.aspx#features_not_included_in_the_net_framework_client_profile
[webapi_selfhost02.png]: /images/20220715/9131a472218f4565936c8008c7233007.png
[webapi_selfhost03.png]: /images/20220715/43a813a142514f5787f1278561860304.png
[webapi_selfhost04.png]: /images/20220715/9410f9457d3943c797f030fceffe9aec.png
[Getting Started]: https://www.asp.net/web-api/overview/getting-started-with-aspnet-web-api/tutorial-your-first-web-api
[webapi_selfhost05.png]: /images/20220715/c9f4e7a9d6b3413c8e6961e3f7ca995d.png
[webapi_selfhost06.png]: /images/20220715/9532958e9de0471dbcd81f41a76ecd16.png
[Calling a Web API From a .NET Client]: https://www.asp.net/web-api/overview/web-api-clients/calling-a-web-api-from-a-net-client
[webapi_selfhost07.png]: /images/20220715/506d543bfbde4a9eb4311a2919e42ebe.png
[Mike Wasson 1]: /images/20220715/02965333c3624bbcad11c6a11cd33386.png