路由与终结点：如何规划好Web Api

1. 路由

1.1 路由映射

路由系统核心作用是指URL和应用程序Controller的对应关系的一种映射
这种映射的作用:

1.把URL映射到对应的Controller的action上
2.根据Controller和action的名字生成URL

1.2 路由注册方式

路由模板的方式 ⇒ 传统方式，可作为MVC页面的Web配置
RouteAttribute方式 ⇒ 更适合Web Api

1.3 路由约束

路由约束指的是路由如何匹配

类型约束
范围约束
正则约束
是否必选
自定义IRouteConstraint

根据路由信息URL生成地址的类

LinkGenerator
IUrlHelper

		/// <summary>
        /// 类型约束
        /// </summary>
        /// <param name="id">必须可以转long</param>
        /// <returns></returns>
        [HttpGet("{id:MyRouteConstraint}")]
        public bool OrderExist(object id)
        {
            return true;
        }

        /// <summary>
        /// 范围约束
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        [HttpGet("{id:max(20)}")]
        public bool Max(long id)
        {
            return true;
        }

        /// <summary>
        /// 是否必选
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        [HttpGet("{name:required}")]
        public bool Reque(string name)
        {
            return true;
        }

        /// <summary>
        /// 正则约束
        /// </summary>
        /// <param name="number"></param>
        /// <returns></returns>
        [HttpGet("{number:regex(^\\d{{3}}$)}")]
        public bool Bumber(string number)
        {

            return true;
        }

// 自定义IRouteConstraint
// 自定义路由约束类
public class MyRouteConstraint : IRouteConstraint
{
    public bool Match(HttpContext httpContext, IRouter route, string routeKey, RouteValueDictionary values, RouteDirection routeDirection)
     {
         if (RouteDirection.IncomingRequest == routeDirection)
         {
             var v= values[routeKey];
             if (long.TryParse(v.ToString(),out var value))
             {
                 return true;
             }
         }
         return false;
     }
 }

// startup中ConfigureServices
services.AddRouting(options =>
{
    options.ConstraintMap.Add("MyRouteConstraint", typeof(MyRouteConstraint));
});


[HttpGet("{id:MyRouteConstraint}")]
public bool OrderExist([FromRoute]string id)
{
    return true;
}

LinkGenerator生成Url

[HttpGet("{id:max(20)}")]
public bool Max([FromRoute] long id, [FromServices] LinkGenerator linkGenerator)
{
      var a = linkGenerator.GetPathByAction(HttpContext,
          action: "Reque",
          controller: "Order",
          values: new { name = "abc" });

      var uri = linkGenerator.GetUriByAction(HttpContext,
          action: "Reque",
          controller: "Order",
          values: new { name = "abc" });
      return true;

  }