首页 > 代码库 > [转]用Middleware给ASP.NET Core Web API添加自己的授权验证
[转]用Middleware给ASP.NET Core Web API添加自己的授权验证
本文转自：http://www.cnblogs.com/catcher1994/p/6021046.html
Web API，是一个能让前后端分离、解放前后端生产力的好东西。不过大部分公司应该都没能做到完全的前后端分离。API的实现方式有很
多，可以用ASP.NET Core、也可以用ASP.NET Web API、ASP.NET MVC、NancyFx等。说到Web API，不同的人有不同的做法，可能前台、
中台和后台各一个api站点，也有可能一个模块一个api站点，也有可能各个系统共用一个api站点，当然这和业务有必然的联系。
安全顺其自然的成为Web API关注的重点之一。现在流行的OAuth 2.0是个很不错的东西，不过本文是暂时没有涉及到的，只是按照最最最
原始的思路做的一个授权验证。在之前的MVC中，我们可能是通过过滤器来处理这个身份的验证，在Core中，我自然就是选择Middleware来处
理这个验证。
下面开始本文的正题：
先编写一个能正常运行的api，不进行任何的权限过滤。
1 using Dapper; 2 using Microsoft.AspNetCore.Mvc; 3 using System.Data; 4 using System.Linq; 5 using System.Threading.Tasks; 6 using WebApi.CommandText; 7 using WebApi.Common; 8 using Common; 9 10 namespace WebApi.Controllers11 {12 [Route("api/[controller]")]13 public class BookController : Controller14 {15 16 private DapperHelper _helper;17 public BookController(DapperHelper helper)18 {19 this._helper = helper;20 }21 22 // GET: api/book23 [HttpGet]24 public async Task<IActionResult> Get()25 {26 var res = await _helper.QueryAsync(BookCommandText.GetBooks);27 CommonResult<Book> json = new CommonResult<Book>28 {29 Code = "000",30 Message = "ok",31 Data =http://www.mamicode.com/ res32 };33 return Ok(json);34 }35 36 // GET api/book/537 [HttpGet("{id}")]38 public IActionResult Get(int id)39 {40 DynamicParameters dp = new DynamicParameters();41 dp.Add("@Id", id, DbType.Int32, ParameterDirection.Input);42 var res = _helper.Query<Book>(BookCommandText.GetBookById, dp, null, true, null, CommandType.StoredProcedure).FirstOrDefault();43 CommonResult<Book> json = new CommonResult<Book>44 {45 Code = "000",46 Message = "ok",47 Data =http://www.mamicode.com/ res48 };49 return Ok(json);50 }51 52 // POST api/book 53 [HttpPost]54 public IActionResult Post([FromForm]PostForm form)55 {56 DynamicParameters dp = new DynamicParameters();57 dp.Add("@Id", form.Id, DbType.Int32, ParameterDirection.Input);58 var res = _helper.Query<Book>(BookCommandText.GetBookById, dp, null, true, null, CommandType.StoredProcedure).FirstOrDefault();59 CommonResult<Book> json = new CommonResult<Book>60 {61 Code = "000",62 Message = "ok",63 Data =http://www.mamicode.com/ res64 };65 return Ok(json);66 }67 68 }69 70 public class PostForm71 {72 public string Id { get; set; }73 }74 75 } api这边应该没什么好说的，都是一些常规的操作，会MVC的应该都可以懂。主要是根据id获取图书信息的方法(GET和POST)。这是我们后
面进行单元测试的两个主要方法。这样部署得到的一个API站点，是任何一个人都可以访问http://yourapidomain.com/api/book 来得到相关
的数据。现在我们要对这个api进行一定的处理，让只有权限的站点才能访问它。
下面就是编写自定义的授权验证中间件了。
Middleware这个东西大家应该都不会陌生了，OWIN出来的时候就有中间件这样的概念了，这里就不展开说明，在ASP.NET Core中是如何
实现这个中间件的可以参考官方文档 Middleware。
我们先定义一个我们要用到的option，ApiAuthorizedOptions
1 namespace WebApi.Middlewares 2 { 3 public class ApiAuthorizedOptions 4 { 5 //public string Name { get; set; } 6 7 public string EncryptKey { get; set; } 8 9 public int ExpiredSecond { get; set; }10 }11 }option内容比较简单，一个是EncryptKey ，用于对我们的请求参数进行签名，另一个是ExpiredSecond ，用于检验我们的请求是否超时。
与之对应的是在appsettings.json中设置的ApiKey节点
1 "ApiKey": {2 //"username": "123",3 //"password": "123",4 "EncryptKey": "@*api#%^@",5 "ExpiredSecond": "300"6 }有了option，下面就可以编写middleware的内容了
我们的api中就实现了get和post的方法，所以这里也就对get和post做了处理，其他http method，有需要的可以自己补充。
这里的验证主要是下面的几个方面：
1.参数是否被篡改
2.请求是否已经过期
3.请求的应用是否合法
主检查方法：Check
1 /// <summary> 2 /// the main check method 3 /// </summary> 4 /// <param name="context"></param> 5 /// <param name="requestInfo"></param> 6 /// <returns></returns> 7 private async Task Check(HttpContext context, RequestInfo requestInfo) 8 { 9 string computeSinature = HMACMD5Helper.GetEncryptResult($"{requestInfo.ApplicationId}-{requestInfo.Timestamp}-{requestInfo.Nonce}", _options.EncryptKey);10 double tmpTimestamp;11 if (computeSinature.Equals(requestInfo.Sinature) &&12 double.TryParse(requestInfo.Timestamp, out tmpTimestamp))13 {14 if (CheckExpiredTime(tmpTimestamp, _options.ExpiredSecond))15 {16 await ReturnTimeOut(context);17 }18 else19 {20 await CheckApplication(context, requestInfo.ApplicationId, requestInfo.ApplicationPassword);21 }22 }23 else24 {25 await ReturnNoAuthorized(context);26 }27 }Check方法带了2个参数，一个是当前的httpcontext对象和请求的内容信息，当签名一致，并且时间戳能转化成double时才去校验是否超时
和Applicatioin的相关信息。这里的签名用了比较简单的HMACMD5加密，同样是可以换成SHA等加密来进行这一步的处理，加密的参数和规则是
随便定的，要有一个约定的过程，缺少灵活性(就像跟银行对接那样，银行说你就要这样传参数给我，不这样就不行，只好乖乖从命)。
Check方法还用到了下面的4个处理
1.子检查方法--超时判断CheckExpiredTime
1 /// <summary> 2 /// check the expired time 3 /// </summary> 4 /// <param name="timestamp"></param> 5 /// <param name="expiredSecond"></param> 6 /// <returns></returns> 7 private bool CheckExpiredTime(double timestamp, double expiredSecond) 8 { 9 double now_timestamp = (DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds;10 return (now_timestamp - timestamp) > expiredSecond;11 }这里取了当前时间与1970年1月1日的间隔与请求参数中传过来的时间戳进行比较，是否超过我们在appsettings中设置的那个值，超过就是
超时了，没超过就可以继续下一个步骤。
2.子检查方法--应用程序判断CheckApplication
应用程序要验证什么呢？我们会给每个应用程序创建一个ID和一个访问api的密码，所以我们要验证这个应用程序的真实身份，是否是那些
有权限的应用程序。
1 /// <summary> 2 /// check the application 3 /// </summary> 4 /// <param name="context"></param> 5 /// <param name="applicationId"></param> 6 /// <param name="applicationPassword"></param> 7 /// <returns></returns> 8 private async Task CheckApplication(HttpContext context, string applicationId, string applicationPassword) 9 {10 var application = GetAllApplications().Where(x => x.ApplicationId == applicationId).FirstOrDefault();11 if (application != null)12 {13 if (application.ApplicationPassword != applicationPassword)14 {15 await ReturnNoAuthorized(context);16 }17 }18 else19 {20 await ReturnNoAuthorized(context);21 }22 }先根据请求参数中的应用程序id去找到相应的应用程序，不能找到就说明不是合法的应用程序，能找到再去验证其密码是否正确，最后才确
定其能否取得api中的数据。
下面两方法是处理没有授权和超时处理的实现:
没有授权的返回方法ReturnNoAuthorized
1 /// <summary> 2 /// not authorized request 3 /// </summary> 4 /// <param name="context"></param> 5 /// <returns></returns> 6 private async Task ReturnNoAuthorized(HttpContext context) 7 { 8 BaseResponseResult response = new BaseResponseResult 9 {10 Code = "401",11 Message = "You are not authorized!"12 };13 context.Response.StatusCode = 401;14 await context.Response.WriteAsync(JsonConvert.SerializeObject(response));15 }这里做的处理是将响应的状态码设置成401(Unauthorized)。
超时的返回方法ReturnTimeOut
1 /// <summary> 2 /// timeout request 3 /// </summary> 4 /// <param name="context"></param> 5 /// <returns></returns> 6 private async Task ReturnTimeOut(HttpContext context) 7 { 8 BaseResponseResult response = new BaseResponseResult 9 {10 Code = "408",11 Message = "Time Out!"12 };13 context.Response.StatusCode = 408;14 await context.Response.WriteAsync(JsonConvert.SerializeObject(response));15 }这里做的处理是将响应的状态码设置成408(Time Out)。
下面就要处理Http的GET请求和POST请求了。
HTTP GET请求的处理方法GetInvoke
1 /// <summary> 2 /// http get invoke 3 /// </summary> 4 /// <param name="context"></param> 5 /// <returns></returns> 6 private async Task GetInvoke(HttpContext context) 7 { 8 var queryStrings = context.Request.Query; 9 RequestInfo requestInfo = new RequestInfo10 {11 ApplicationId = queryStrings["applicationId"].ToString(),12 ApplicationPassword = queryStrings["applicationPassword"].ToString(),13 Timestamp = queryStrings["timestamp"].ToString(),14 Nonce = queryStrings["nonce"].ToString(),15 Sinature = queryStrings["signature"].ToString()16 };17 await Check(context, requestInfo);18 }处理比较简单，将请求的参数赋值给RequestInfo，然后将当前的httpcontext和这个requestinfo交由我们的主检查方法Check去校验
这个请求的合法性。
同理，HTTP POST请求的处理方法PostInvoke，也是同样的处理。
1 /// <summary> 2 /// http post invoke 3 /// </summary> 4 /// <param name="context"></param> 5 /// <returns></returns> 6 private async Task PostInvoke(HttpContext context) 7 { 8 var formCollection = context.Request.Form; 9 RequestInfo requestInfo = new RequestInfo10 {11 ApplicationId = formCollection["applicationId"].ToString(),12 ApplicationPassword = formCollection["applicationPassword"].ToString(),13 Timestamp = formCollection["timestamp"].ToString(),14 Nonce = formCollection["nonce"].ToString(),15 Sinature = formCollection["signature"].ToString()16 };17 await Check(context, requestInfo);18 }最后是Middleware的构造函数和Invoke方法。
1 public ApiAuthorizedMiddleware(RequestDelegate next, IOptions<ApiAuthorizedOptions> options) 2 { 3 this._next = next; 4 this._options = options.Value; 5 } 6 7 public async Task Invoke(HttpContext context) 8 { 9 switch (context.Request.Method.ToUpper())10 {11 case "POST":12 if (context.Request.HasFormContentType)13 {14 await PostInvoke(context);15 }16 else17 {18 await ReturnNoAuthorized(context);19 }20 break;21 case "GET":22 await GetInvoke(context);23 break;24 default:25 await GetInvoke(context);26 break;27 }28 await _next.Invoke(context);29 }到这里，Middleware是已经编写好了，要在Startup中使用，还要添加一个拓展方法ApiAuthorizedExtensions
1 using Microsoft.AspNetCore.Builder; 2 using Microsoft.Extensions.Options; 3 using System; 4 5 namespace WebApi.Middlewares 6 { 7 public static class ApiAuthorizedExtensions 8 { 9 public static IApplicationBuilder UseApiAuthorized(this IApplicationBuilder builder)10 {11 if (builder == null)12 {13 throw new ArgumentNullException(nameof(builder));14 }15 16 return builder.UseMiddleware<ApiAuthorizedMiddleware>();17 }18 19 public static IApplicationBuilder UseApiAuthorized(this IApplicationBuilder builder, ApiAuthorizedOptions options)20 {21 if (builder == null)22 {23 throw new ArgumentNullException(nameof(builder));24 }25 26 if (options == null)27 {28 throw new ArgumentNullException(nameof(options));29 }30 31 return builder.UseMiddleware<ApiAuthorizedMiddleware>(Options.Create(options));32 }33 }34 }到这里我们已经可以在Startup的Configure和ConfigureServices方法中配置这个中间件了
这里还有一个不一定非要实现的拓展方法ApiAuthorizedServicesExtensions，但我个人还是倾向于实现这个ServicesExtensions。
1 using Microsoft.Extensions.DependencyInjection; 2 using System; 3 4 namespace WebApi.Middlewares 5 { 6 public static class ApiAuthorizedServicesExtensions 7 { 8 9 /// <summary>10 /// Add response compression services.11 /// </summary>12 /// <param name="services">The <see cref="IServiceCollection"/> for adding services.</param>13 /// <returns></returns>14 public static IServiceCollection AddApiAuthorized(this IServiceCollection services)15 {16 if (services == null)17 {18 throw new ArgumentNullException(nameof(services));19 }20 21 return services;22 }23 24 /// <summary>25 /// Add response compression services and configure the related options.26 /// </summary>27 /// <param name="services">The <see cref="IServiceCollection"/> for adding services.</param>28 /// <param name="configureOptions">A delegate to configure the <see cref="ResponseCompressionOptions"/>.</param>29 /// <returns></returns>30 public static IServiceCollection AddApiAuthorized(this IServiceCollection services, Action<ApiAuthorizedOptions> configureOptions)31 {32 if (services == null)33 {34 throw new ArgumentNullException(nameof(services));35 }36 if (configureOptions == null)37 {38 throw new ArgumentNullException(nameof(configureOptions));39 }40 41 services.Configure(configureOptions);42 return services;43 }44 }45 }为什么要实现这个拓展方法呢？个人认为
Options、Middleware、Extensions、ServicesExtensions这四个是实现一个中间件的标配(除去简单到不行的那些中间件)
Options给我们的中间件提供了一些可选的处理，提高了中间件的灵活性；
Middleware是我们中间件最最重要的实现；
Extensions是我们要在Startup的Configure去表明我们要使用这个中间件；
ServicesExtensions是我们要在Startup的ConfigureServices去表明我们把这个中间件添加到容器中。
下面是完整的Startup
1 using Microsoft.AspNetCore.Builder; 2 using Microsoft.AspNetCore.Hosting; 3 using Microsoft.Extensions.Configuration; 4 using Microsoft.Extensions.DependencyInjection; 5 using Microsoft.Extensions.Logging; 6 using System; 7 using WebApi.Common; 8 using WebApi.Middlewares; 9 10 namespace WebApi11 {12 public class Startup13 {14 public Startup(IHostingEnvironment env)15 {16 var builder = new ConfigurationBuilder()17 .SetBasePath(env.ContentRootPath)18 .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)19 .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);20 21 if (env.IsEnvironment("Development"))22 {23 // This will push telemetry data through Application Insights pipeline faster, allowing you to view results immediately.24 builder.AddApplicationInsightsSettings(developerMode: true);25 }26 27 builder.AddEnvironmentVariables();28 Configuration = builder.Build();29 }30 31 public IConfigurationRoot Configuration { get; }32 33 // This method gets called by the runtime. Use this method to add services to the container34 public void ConfigureServices(IServiceCollection services)35 {36 // Add framework services.37 services.AddApplicationInsightsTelemetry(Configuration);38 services.Configure<IISOptions>(options =>39 {40 41 });42 43 services.Configure<DapperOptions>(options =>44 {45 options.ConnectionString = Configuration.GetConnectionString("DapperConnection");46 });47 48 //api authorized middleware49 services.AddApiAuthorized(options =>50 {51 options.EncryptKey = Configuration.GetSection("ApiKey")["EncryptKey"];52 options.ExpiredSecond = Convert.ToInt32(Configuration.GetSection("ApiKey")["ExpiredSecond"]);53 });54 55 56 services.AddMvc();57 58 services.AddSingleton<DapperHelper>();59 }60 61 // This method gets called by the runtime. Use this method to configure the HTTP request pipeline62 public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)63 {64 65 loggerFactory.AddConsole(Configuration.GetSection("Logging"));66 loggerFactory.AddDebug();67 68 app.UseDapper();69 70 //api authorized middleware71 app.UseApiAuthorized();72 73 app.UseApplicationInsightsRequestTelemetry();74 75 app.UseApplicationInsightsExceptionTelemetry();76 77 app.UseMvc();78 }79 }80 }万事具备，只欠测试！！
建个类库项目，写个单元测试看看。
1 using Common; 2 using Newtonsoft.Json; 3 using System; 4 using System.Collections.Generic; 5 using System.Net.Http; 6 using System.Threading.Tasks; 7 using Xunit; 8 9 namespace WebApiTest10 {11 public class BookApiTest12 {13 private HttpClient _client;14 private string applicationId = "1";15 private string applicationPassword = "123";16 private string timestamp = (DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalSeconds.ToString();17 private string nonce = new Random().Next(1000, 9999).ToString();18 private string signature = string.Empty;19 20 public BookApiTest()21 {22 _client = new HttpClient();23 _client.BaseAddress = new Uri("http://localhost:8091/");24 _client.DefaultRequestHeaders.Clear();25 signature = HMACMD5Helper.GetEncryptResult($"{applicationId}-{timestamp}-{nonce}", "@*api#%^@");26 }27 28 [Fact]29 public async Task book_api_get_by_id_should_success()30 {31 string queryString = $"applicationId={applicationId}×tamp={timestamp}&nonce={nonce}&signature={signature}&applicationPassword={applicationPassword}";32 33 HttpResponseMessage message = await _client.GetAsync($"api/book/4939?{queryString}");34 var result = JsonConvert.DeserializeObject<CommonResult<Book>>(message.Content.ReadAsStringAsync().Result);35 36 Assert.Equal("000", result.Code);37 Assert.Equal(4939, result.Data.Id);38 Assert.True(message.IsSuccessStatusCode);39 }40 41 [Fact]42 public async Task book_api_get_by_id_should_failure()43 {44 string inValidSignature = Guid.NewGuid().ToString();45 string queryString = $"applicationId={applicationId}×tamp={timestamp}&nonce={nonce}&signature={inValidSignature}&applicationPassword={applicationPassword}";46 47 HttpResponseMessage message = await _client.GetAsync($"api/book/4939?{queryString}");48 var result = JsonConvert.DeserializeObject<CommonResult<Book>>(message.Content.ReadAsStringAsync().Result);49 50 Assert.Equal("401", result.Code);51 Assert.Equal(System.Net.HttpStatusCode.Unauthorized, message.StatusCode); 52 }53 54 [Fact]55 public async Task book_api_post_by_id_should_success()56 { 57 var data = http://www.mamicode.com/new Dictionary<string, string>();58 data.Add("applicationId", applicationId);59 data.Add("applicationPassword", applicationPassword);60 data.Add("timestamp", timestamp);61 data.Add("nonce", nonce);62 data.Add("signature", signature);63 data.Add("Id", "4939");64 HttpContent ct = new FormUrlEncodedContent(data);65 66 HttpResponseMessage message = await _client.PostAsync("api/book", ct);67 var result = JsonConvert.DeserializeObject<CommonResult<Book>>(message.Content.ReadAsStringAsync().Result);68 69 Assert.Equal("000", result.Code);70 Assert.Equal(4939, result.Data.Id);71 Assert.True(message.IsSuccessStatusCode);