ASP.NET Web API 2基于令牌的身份验证

基于令牌的认证

    我们知道WEB网站的身份验证一般通过session或者cookie完成的，登录成功后客户端发送的任何请求都带上cookie，服务端根据客户端发送来的cookie来识别用户。

    WEB API使用这样的方法不是很适合，于是就有了基于令牌的认证，使用令牌认证有几个好处：可扩展性、松散耦合、移动终端调用比较简单等等，别人都用上了，你还有理由不用吗？

    下面我们花个20分钟的时间来实现一个简单的WEB API token认证：

Step 1: 新建一个空的WEB API项目,项目名称就设置为WebApi

Step 2: 在Models目录下新建一个 Product 类 ：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

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

Step 3：在Controllers目录下新建一个 ProductsController 类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Web.Http;

using WebApi.Models;

namespace WebApi.Controllers
{
    [RoutePrefix("api/Products")]
    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));
        }
    }
}

F5运行后就可以使用这个简单的WebApi了，测试api可以使用Postman工具:

    获取所有数据  http://localhost:1234/api/products

    获取内码为1的数据  http://localhost:1234/api/products/1

    查询category=的数据  http://localhost:1234/api/products?category=Groceries

    可以看到这个产品的API是公开访问的，没有任何验证，这样不是很安全，下一步我将加上token验证。

Step 4：安装所需的NuGet包：

打开NuGet包管理器控制台，然后输入如下指令：

Install-Package Microsoft.AspNet.WebApi.Owin -Version 5.1.2
Install-Package Microsoft.Owin.Host.SystemWeb -Version 2.1.0
Install-Package Microsoft.AspNet.Identity.Owin -Version 2.0.1
Install-Package Microsoft.Owin.Cors -Version 2.1.0
Install-Package EntityFramework -Version 6.0.0 

Step 5：在项目根目录下添加Owin“Startup”类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Http;

using Owin;
using Microsoft.Owin;
using Microsoft.Owin.Security.OAuth;

[assembly: OwinStartup(typeof(WebApi.Startup))]
namespace WebApi
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            HttpConfiguration config = new HttpConfiguration();
            ConfigureOAuth(app);

            WebApiConfig.Register(config);
            app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);
            app.UseWebApi(config);
        }

        public void ConfigureOAuth(IAppBuilder app)
        {
            OAuthAuthorizationServerOptions OAuthServerOptions = new OAuthAuthorizationServerOptions()
            {
                AllowInsecureHttp = true,
                TokenEndpointPath = new PathString("/token"),
                AccessTokenExpireTimeSpan = TimeSpan.FromDays(1),
                Provider = new SimpleAuthorizationServerProvider()
            };
            app.UseOAuthAuthorizationServer(OAuthServerOptions);
            app.UseOAuthBearerAuthentication(new OAuthBearerAuthenticationOptions());
        }
    }
}

Step 6：删除Global.asax 

我们已经设置了Setup类，就不需要Global了，删掉干净；

Step 7：在项目根目录下添加验证类 SimpleAuthorizationServerProvider，为了简单用户的验证部分我们省略掉；

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

using System.Threading;
using System.Threading.Tasks;
using Microsoft.Owin;
using Microsoft.Owin.Security.OAuth;
using System.Security.Claims;

namespace WebApi
{
    public class SimpleAuthorizationServerProvider : OAuthAuthorizationServerProvider
    {
        public override async Task ValidateClientAuthentication(OAuthValidateClientAuthenticationContext context)
        {
            context.Validated();
        }

        public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
        {

            context.OwinContext.Response.Headers.Add("Access-Control-Allow-Origin", new[] { "*" });

            /*
             * 对用户名、密码进行数据校验，这里我们省略
            using (AuthRepository _repo = new AuthRepository())
            {
                IdentityUser user = await _repo.FindUser(context.UserName, context.Password);

                if (user == null)
                {
                    context.SetError("invalid_grant", "The user name or password is incorrect.");
                    return;
                }
            }*/

            var identity = new ClaimsIdentity(context.Options.AuthenticationType);
            identity.AddClaim(new Claim("sub", context.UserName));
            identity.AddClaim(new Claim("role", "user"));

            context.Validated(identity);

        }
    }
}

Step 7：让CORS起作用

在ASP.NET Web API中启用OAuth的Access Token验证非常简单，只需在相应的Controller或Action加上[Authorize]标记

修改ProductsController类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Web.Http;

using WebApi.Models;

namespace WebApi.Controllers
{

    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 }  
        };

        [Authorize]
        [Route("")]
        public IEnumerable<Product> GetAllProducts()
        {
            return products;
        }

        [Authorize]
        public Product GetProductById(int id)
        {
            var product = products.FirstOrDefault((p) => p.Id == id);
            if (product == null)
            {
                throw new HttpResponseException(HttpStatusCode.NotFound);
            }
            return product;
        }

        [AllowAnonymous]
        public IEnumerable<Product> GetProductsByCategory(string category)
        {
            return products.Where(p => string.Equals(p.Category, category,
                    StringComparison.OrdinalIgnoreCase));
        }
    }
}

现在我们再次直接GET http://localhost:23477/api/products/ 会返回401错误，请求被拒绝

获取token， POST   http://localhost:23477/token

参数BODY x-www-form-urlencoded 格式：

grant_type=password

username=admin 

password=123456

返回200状态，内容为：

{
  "access_token": "eLjAu3Alm2YWjJKXmX_fLY07P6vbIzxasFECkDap3KIE0Ydp7IGhTgrzWLtPdgrK46rfAB-OmJSG5C8Bh-PkfG3XrGS0uDea2KBXyoWSR11evTGJiVIyXny3Ih2DkH04qH2T_Ar4kIjcAngPtUnsEVex26tV4QHIrjCq5SlkOdfdAa9Pnl98QVwYH47yO-zlc55bwMgpR2J4fQLyNzWVHNZpH3DbOcHQ3Yenemr6XhM",
  "token_type": "bearer",
  "expires_in": 86399
}

只要在http请求头中加上Authorization:bearer Token就可以成功访问API就成功了：

GET   http://localhost:23477/api/products/

Authorization : bearer eLjAu3Alm2YWjJKXmX_fLY07P6vbIzxasFECkDap3KIE0Ydp7IGhTgrzWLtPdgrK46rfAB-OmJSG5C8Bh-PkfG3XrGS0uDea2KBXyoWSR11evTGJiVIyXny3Ih2DkH04qH2T_Ar4kIjcAngPtUnsEVex26tV4QHIrjCq5SlkOdfdAa9Pnl98QVwYH47yO-zlc55bwMgpR2J4fQLyNzWVHNZpH3DbOcHQ3Yenemr6XhM

这样我们就完成了简单的WEB API的token验证~

不过这个程序有个问题，如果GetProductById也加上验证那么根据ID获取product的接口 http://localhost:23477/api/products/1 会报错

需要修改成 http://localhost:23477/api/products?id=1 

不知道是哪里出的问题

本文代码： http://pan.baidu.com/s/1jGxZVKU

PostMan工具请移步这里看介绍 http://www.cnblogs.com/wade-xu/p/4228954.html