c# - 为什么 http get 方法在 asp.net web api 中接受 http post 请求？

Question

我有一个 HTTP-GET 方法，如下所示

[Route("api/[controller]")]
[ApiController]
public class CityController : ControllerBase
{
    public ActionResult Get(int id)
    {
        try
        {
            var city = new { CityName = "Gotham" };
            return Ok(city);
        }
        catch(Exception ex)
        {
            return StatusCode(500);
        }
    }
}

对于这两种类型的请求

要求:

GET http://localhost:49915/api/city
POST http://localhost:49915/api/city

响应:

status: 200 OK
-------------------
{
    "cityName": "Gotham"
}

现在我的问题是，

1. 因为它是一个GET，它应该接受一个POST吗？
2. 它不应该返回 405 状态代码吗？为什么不呢？ (至少我在期待)
3. 在这种情况下，如果我必须返回 405 怎么办？

Answer 1

As it is a GET, should it supposed to accept a POST?

虽然您因为操作名称和基于约定的路由而假设它是一个 get，但您会误以为 Controller 已被修饰为属性路由。

[Route("api/[controller]")]

因此如果匹配则忽略基于约定的路由。请注意 PUT 和 DELETE

PUT http://localhost:49915/api/city
DELETE http://localhost:49915/api/city

也应该对相同的 Action 起作用。

Shouldn't it return a 405 status code and Why it does not? (at least I'm expecting)

由于没有为操作给出指令，因此该操作在设计上与两个调用匹配。

[Route("api/[controller]")]
[ApiController]
public class CityController : ControllerBase {
    // GET api/city?id=2 //Note id would be optional as a query variable.
    [HttpGet]
    public ActionResult Get(int id) {
        try {
            var city = new { CityName = "Gotham" };
            return Ok(city);
        } catch(Exception ex) {
            return StatusCode(500);
        }
    }
}

现在有了HttpGet，如果

POST http://localhost:49915/api/city

或者另一个 HTTP 方法完成后，您将收到 405 错误，因为路径匹配但方法不匹配。

In such case, if I have to return 405 what to be done?

属性路由到位后，框架会为您完成，因此您无需再做任何事。

引用 Routing to controller actions in ASP.NET Core

Mixed routing: Attribute routing vs conventional routing

What distinguishes the two types of routing systems is the process applied after a URL matches a route template. In conventional routing, the route values from the match are used to choose the action and controller from a lookup table of all conventional routed actions. In attribute routing, each template is already associated with an action, and no further lookup is needed.