ASP.NET WebAPI适用于构建HTTP服务的框架，可以从任何客户端（包括浏览器和移动设备）访问它。

它是在.NET Framework上构建RESTful应用程序的理想平台。

ASP.NET Web API初识

  • Web API：是一种使用HTTP协议访问的Web上的API（Application programing Interface），可以使用不同的技术（如Java、.NET等）构建Web API。
  • ASP.NET Web API是一个可扩展的框架，用于构建基于HTTP的服务，可以在不同平台上访问，如Web、Window。
  • 工作方法与ASP.NET MVC Web Application类似，只不过它返回的是数据，而不是视图。
  • 它与Web Service和WCF类型，只不过它只能使用HTTP协议。

ASP.NET Web API特性

  1. ASP.NET Web API构造在ASP.NET之上，支持ASP.NET请求/响应通道
  2. ASP.NET Web API将HTTP谓词映射到方法名称
  3. ASP.NET Web API支持不同格式的响应数据，内置支持JSON、XML、BSON格式
  4. ASP.NET Web API可以托管在IIS、自托管或支持.NET 4.0+的其他Web服务器
  5. ASP.NET Web API使用最新的HttpClient与Web API Server通信

ASP.NET Web API版本

Web API Version Supported .NET Framewok Coincides with Supported in
Web API 1.0 .NET Framework 4.0 ASP.NET MVC 4 VS2010
Web API 2 .NET Framework 4.5 ASP.NET MVC 5 VS2012 、VS2013

ASP.NET Web API与WCF

Web API WCF
开源并运行.NET框架 运行.NET框架
仅支持HTTP协议 支持HTTP、TCP、UDP和自定义协议
将HTTP谓词映射到方法 使用基于属性的编程模型
使用类似ASP.NET MVC路由和控制器概念 使用服务、操作、数据契约
不支持可靠的消息传递和事务 支持可靠的消息传递和事务
使用HttpConfiguration类配置Web API，不能在Web.config中配置 使用Web.config和属性配置服务
非常适合构建RestFul服务 支持构建RestFul服务，但有限制

选择Web API

  • 使用.NET Framework 4.0或者更高版本
  • 构建仅支持HTTP协议的服务
  • 构建基于RestFul HTTP服务
  • 熟悉ASP.NET MVC

选择WCF

  • 使用.NET Framework 3.5
  • 服务需要支持多种协议
  • 使用WS-*标准构建服务
  • 使用Request-Reply、One Way和Duplex message exchange

ASP.NET Web API创建

Web API With MVC Project

ASP.NET Web Application==>Web API

  1. New Project–>ASP.NET Web Application–>Web API

CreateWebAPIWithMVC.jpg

CreateWepAPI.jpg

  1. 自动生成配置App_Start：WebApiConfig.cs 

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    //配置访问路由
    namespace MyWepAPIWithMVC
    {
        public static class WebApiConfig
        {
            public static void Register(HttpConfiguration config)
            {
                // Web API configuration and services

                // Web API routes
                config.MapHttpAttributeRoutes();

                config.Routes.MapHttpRoute(
                    name: "DefaultApi",
                    routeTemplate: "api/{controller}/{id}",
                    defaults: new { id = RouteParameter.Optional }
                );
            }
        }
    }

  2. 自动生成WebApi类：ValuesController.cs

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    //继承ApiController抽象类
    //默认方法映射Http谓词，如Get,Post,Put,Delete等
    namespace MyWepAPIWithMVC.Controllers
    {
        public class ValuesController : ApiController
        {
            // GET api/values
            public IEnumerable<string> Get()
            {
                return new string[] { "value1", "value2" };
            }

            // GET api/values/5
            public string Get(int id)
            {
                return "value";
            }

            // POST api/values
            public void Post([FromBody]string value)
            {
            }

            // PUT api/values/5
            public void Put(int id, [FromBody]string value)
            {
            }

            // DELETE api/values/5
            public void Delete(int id)
            {
            }
        }
    }

    WebAPIWithMVC配置.jpg

  3. 自动注册：Global.asax

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    namespace MyWepAPIWithMVC
    {
        public class WebApiApplication : System.Web.HttpApplication
        {
            protected void Application_Start()
            {
                AreaRegistration.RegisterAllAreas();
                //启动配置WepAPI
                GlobalConfiguration.Configure(WebApiConfig.Register);
                FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
                RouteConfig.RegisterRoutes(RouteTable.Routes);
                BundleConfig.RegisterBundles(BundleTable.Bundles);
            }
        }
    }

Stand-alone Web API Projcet

ASP.NET Web Application==>Empty

  1. New Project–>ASP.NET Web Application–>Empty

    CreateWebAPIWithEmpty.jpg

  2. 手动配置

    • 安装WebAPI类库：Micresoft ASP.NET Web API 2.2

      WebAPI依赖包安装.jpg

    • 添加Configuration文件夹，创建配置类

      WepAPI手动配置.jpg

    • 添加应用程序类Global.asax，启动配置

      WepAPI手动启动配置.jpg

  3. 手动创建WebAPI类

    手动创建WebAPI类.jpg

ASP.NET Web API测试

Fiddler

Postman

ASP.NET Web API配置

Web API支持基于代码的配置，无法在配置文件如，Web.config中配置。

启动配置

​ GlobalConfiguration.Configure(WebApiConfig.Register);

路由配置

​ WebApiConfigure.Register(config)->config.Routes

ASP.NET Web API路由

Convention-based Routing（基于约定）

  • 使用路由模板决定执行哪个Controller和Action。
  • 路由表里面至少添加一个路由模板
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//多种路由，会按照先后顺序匹配
//一般将默认路由，放在最下面
namespace MyWepAPIWithMVC
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
           //1.使用路由模板通过MapHttpRoute方法创建一个新的路由对象，添加到路由表中
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
          //2.自定义路由对象，添加到路由表中
             IHttpRoute defaultRoute = config.Routes.CreateRoute("api/{controller}/{id}", new { id = RouteParameter.Optional }, null);
            config.Routes.Add("DefultApi", defaultRoute);
        }
          //3.配置多种路由，添加到路由表中
       		//School Route
             config.Routes.MapHttpRoute(
                name: "School",
                routeTemplate: "api/myschoole/{id}",
                defaults: new { controller = "school", id = RouteParameter.Optional },
                constraints: new { id = "/d+" }
                );
    }
}

Attribute Routing（基于属性）

  • 使用路由属性[Route(“xxx”)]定义路由，可以配置Controller或Action上
  • 使用路由属性必须启用：config.MapHttpAttributeRoutes();
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[Route("api/MyWebAPI/MyGet")]
public string GetMy()
{
    return "It's My Get By Route Attribute";
}

ASP.NET Web API参数

primitive type（原始类型）

参数值来源于：query string

complex type（复杂类型）

参数值来源于：request body

参数默认绑定规则

HTTP Method Query String Request Body
GET Primitive Type,Complex Type NA
POST Primitive Type Complex Type
PUT Primitive Type Complex Type
PATCH Primitive Type Complext Type
DELETE Primitive Type,Complex Type NA
  • GET请求

参数顺序和大小写无关，名称要相同

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//WebAPI
public class StudentController : ApiController
{
    //1.GET请求
    public Student Get(int id) 
    {
              
    }
    //2.GET请求
    public Student Get(int id,string anme) 
    {
              
    }
}
//1.GET请求：
//http://localhost/api/student?id=1
//http://localhost/api/student?ID=1

//2.GET请求：
//http://localhost/api/student?id=1&name=steve
//http://localhost/api/student?ID=1&NAME=steve
//http://localhost/api/student?name=steve&id=1
  • POST请求
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public class StudentController : ApiController
{
	//1.POST请求：原始类型
    public Student Post(id id, string name)
    {
           
    }
    //2.POST请求：复杂类型
    public class StudentController : ApiController
    {
        public Student Post(Student stud)
        {

        }
    }	
}

public class Student
{
    public int Id { get; set; }
    public string Name { get; set; }
}

//1.POST请求：从Query String获取参数值
//http://localhost/api/student?id=1&name=steve
//2.POST请求：从Request Body获取参数值
//http://localhost/api/student

参数默认规则修改

  • [FormUri]

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    public class StudentController : ApiController
    {
        public Student Post([FromUri]Student stud)
        {

        }
    }
    //Web API从请求字符串(Query String)中解析参数，而不是请求体（Request Body）

  • [FormBody]

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    public class StudentController : ApiController
    {
        public Student Post([FromBody]string name)
        {

        }
    }
    //Web API从请求体（Request Body）中解析参数，而不是请求字符串（Query String）

ASP.NET Web API返回类型

  • Void
  • Primitive type or Complex type
  • HttpResponseMessage
  • IHttpActionResult

Web API Controller

Web API 控制器是一个类，名称必须以Controller结尾，且从System.Web.Http.ApiController派生。所有公共方法都称为操作方法。

  • 默认操作方法，与HTTP谓词匹配

    • GET / POST / PUT / PATCH / DELETE

    • 方法名与HTTP谓词相同，或者以谓词开头

HTTP Method Possible Action Name Usage
GET Get() any name starting with Get Retrieves data.
POST Post() any name starting with Post Inserts new record.
PUT Put() any name starting with Put Updates existing record.
PATCH Patch() any name starting with Patch Updates record partially.
DELETE Delete() any name starting with Delete Deletes record.

  • 自定义方法名，使用HTTP谓词属性

    • HttpGet，HttpPost，HttpPut，HttpDelete等

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      [HttpGet]
      public string Value(int id)
      {
          return "value";
      }

ASP.NET Web API 过滤器

Web API 过滤器用于在执行操作方法之前或者之后添加额外逻辑。如日志记录、异常处理、性能测量、身份验证和授权。

过滤器实际上是应用在Web API Controller或者action上的属性。每一个Filter必须实现System.Web.Http.Filters.IFilter接口。

重要的Filter接口：

Filter Type Interfacce Class Description
Simple Filter IFilter - Defines the methods that are used in a filter
Action Filter IActionFilter ActionFilterAttribute Used to add extra logic before or after action methods execute
Authentication Filter IAuthenticationFilter - Used to force users or clients to be authenticated before action methods execute
Authorization Filter IAuthorizationFilter AuthorizationFilterAttribute Used to restrict access to action methods to specific users or groups
Exception Filter IExceptionFilter ExceptionFilterAttribute Used to handle all unhandled exception in Web API
Override Filter IOverrideFilter - Used to customize the behavior of othe filter for individual action method

接口：需要自己实现，抽象类：需要自己重写。

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//LogAttribute继承抽象类ActionFilterAttribute
//重写OnActionExecuting方法和OnActionExecuted方法
namespace MyWebAPIWithNone.Filter
{
    public class LogAttirbute : ActionFilterAttribute
    {
        public LogAttirbute()
        { }

        public override void OnActionExecuting(HttpActionContext actionContext)
        {
            Trace.WriteLine(string.Format("Action Method {0} executing at{1}", actionContext.ActionDescriptor.ActionName, DateTime.Now.ToShortDateString()), "Web API Logs");
        }

        public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
        {
            Trace.WriteLine(string.Format("Action Method {0} executed at{1}", actionExecutedContext.ActionContext.ActionDescriptor.ActionName, DateTime.Now.ToShortDateString()), "Web API Logs");
        }
    }
}
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//Log2Attribute继承Attribute抽象类，并实现IActionFilter接口
namespace MyWebAPIWithNone.Filter
{
    public class Log2Attribute : Attribute, IActionFilter
    {
        public Log2Attribute()
        { }
        public Task<HttpResponseMessage> ExecuteActionFilterAsync(HttpActionContext actionContext, CancellationToken cancellationToken, Func<Task<HttpResponseMessage>> continuation)
        {
            Trace.WriteLine(string.Format("Action Method {0} executing at{1}", actionContext.ActionDescriptor.ActionName, DateTime.Now.ToShortDateString()), "Web API Logs");

            var result = continuation();

            result.Wait();

            Trace.WriteLine(string.Format("Action Method {0} executed at{1}", actionContext.ActionDescriptor.ActionName, DateTime.Now.ToShortDateString()), "Web API Logs");

            return result;
        }

        public bool AllowMultiple
        {
            get { return true; }
        }
    }
}
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namespace MyWebAPIWithNone.Controller
{
    public class MyWebAPIController : ApiController
    {
        [Log]
        public string Get()
        {
            return "It's My Web API";
        }
        [Log2]
        [Route("api/MyWebAPI/MyGet")]
        public string GetMy()
        {
            return "It's My Get By Route Attribute";
        }
    }
}
//执行输出：
//Web API Logs: Action Method Get executing at2018/9/10
//Web API Logs: Action Method Get executed at2018/9/10
//Web API Logs: Action Method GetMy executing at2018/9/10
//Web API Logs: Action Method GetMy executed at2018/9/10

ASP.NET Web API 通信

WebClient

​ .NET 2.0 使用WebClient与Web Server通信

HttpClient

​ .NET 4.5 使用HttpClient与Web Server通信

HttpClient方法

详见：HttpClient.aspx)

Method Name Descirption
GetAsync Sends a GET request to the specified Uri as an asynchronous operation
GetByteArrayAsync Sends a GET request to the specified Uri and returns the response body as a byte array in an asynchronous operation
GetStreamAsync Sends a GET request to the specified Uri and returns the response body as a stream in an asynchronous operation
GetStringAsync Sends a GET request to the specified Uri and returns the response body as a string in an asynchronous operation
PostAsync Sends a POST request to the specified Uri as an asynchronous operation
PostAsJsonAsync Sends a POST request as an asynchronous operation to the specified Uri with given value serialized as JSON
PostAsXmlAsync Sends a POST request as an asynchronous operation to the specified Uri with given value serialized as XML
PutAsync Sends a PUT request to the specified Uri as an asynchronous operation
PutAsJsonAsync Sends a PUT request as an asynchronous operation to the specified Uri with the given value serialized as JSON
PutAsXmlAsync Sends a PUT request as an asynchronous operation to the specified Uri with the given value serialized as XML
DeletelAsync Sends a DELETE request to the specified Uri as an asynchronous operation 
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//例如获取学生信息
using(var client = new HttpClient())
{
  client.BaseAddress = new Uri("http://localhost/api");
  
  var responseTask = client.GetAsync("student");
  responseTask.Wait();
  
  var result = responseTask.Result;
  if(result.IsSuccessStatusCode)
  {
    var readTask = result.Content.ReadAsync<Student>();
    readTask.Wait();
    
    var student = readTask.Result;
    
    ......
  }
  
}

ASP.NET Web API Hosting

IIS Hosting

Self Hosting

最后更新： 2018年09月16日 15:24

原始链接： https://www.github.com/ChangHub/BlogImages/raw/master/2018/09/08/ASP.NET MVC WebAPI/

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