Routing and Action Selection in ASP.NET Web API
https://exceptionnotfound.net/using-http-methods-correctly-in-asp-net-web-api/
The algorithm ASP.NET uses to calculate the "default" method for a given action goes like this:
Action Selection
After selecting the controller, the framework selects the action by calling the IHttpActionSelector.SelectAction method. This method takes an HttpControllerContext and returns an HttpActionDescriptor.
The default implementation is provided by the ApiControllerActionSelector class. To select an action, it looks at the following:
- The HTTP method of the request.
- The "{action}" placeholder in the route template, if present.
- The parameters of the actions on the controller.
Before looking at the selection algorithm, we need to understand some things about controller actions.
Which methods on the controller are considered "actions"? When selecting an action, the framework only looks at public instance methods on the controller. Also, it excludes "special name" methods (constructors, events, operator overloads, and so forth), and methods inherited from the ApiController class.
HTTP Methods. The framework only chooses actions that match the HTTP method of the request, determined as follows:
- You can specify the HTTP method with an attribute: AcceptVerbs, HttpDelete, HttpGet, HttpHead, HttpOptions, HttpPatch, HttpPost, or HttpPut.
- Otherwise, if the name of the controller method starts with "Get", "Post", "Put", "Delete", "Head", "Options", or "Patch", then by convention the action supports that HTTP method.
- If none of the above, the method supports POST.
Parameter Bindings. A parameter binding is how Web API creates a value for a parameter. Here is the default rule for parameter binding:
- Simple types are taken from the URI.
- Complex types are taken from the request body.
Simple types include all of the .NET Framework primitive types, plus DateTime, Decimal, Guid, String, and TimeSpan. For each action, at most one parameter can read the request body.
Note:It is possible to override the default binding rules. See WebAPI Parameter binding under the hood.
微软官方的parameter binding文章
With that background, here is the action selection algorithm.
Create a list of all actions on the controller that match the HTTP request method.
If the route dictionary has an "action" entry, remove actions whose name does not match this value.
Try to match action parameters to the URI, as follows:
- For each action, get a list of the parameters that are a simple type, where the binding gets the parameter from the URI. Exclude optional parameters.
- From this list, try to find a match for each parameter name, either in the route dictionary or in the URI query string. Matches are case insensitive and do not depend on the parameter order.
- Select an action where every parameter in the list has a match in the URI.
- If more that one action meets these criteria, pick the one with the most parameter matches.
Ignore actions with the [NonAction] attribute.
Step #3 is probably the most confusing. The basic idea is that a parameter can get its value either from the URI, from the request body, or from a custom binding. For parameters that come from the URI, we want to ensure that the URI actually contains a value for that parameter, either in the path (via the route dictionary) or in the query string.
Routing and Action Selection in ASP.NET Web API的更多相关文章
- Asp.Net Web API VS Asp.Net MVC
http://www.dotnet-tricks.com/Tutorial/webapi/Y95G050413-Difference-between-ASP.NET-MVC-and-ASP.NET-W ...
- ASP.NET Web API 2.0新特性:Attribute Routing1
ASP.NET Web API 2.0新特性:Attribute Routing[上篇] 对于一个针对ASP.NET Web API的调用请求来说,请求的URL和对应的HTTP方法的组合最终决定了目标 ...
- Asp.net web api 知多少
本系列主要翻译自<ASP.NET MVC Interview Questions and Answers >- By Shailendra Chauhan,想看英文原版的可访问http:/ ...
- ASP.NET Web API中的Routing(路由)
[译]Routing in ASP.NET Web API 单击此处查看原文 本文阐述了ASP.NET Web API是如何将HTTP requests路由到controllers的. 如果你对ASP ...
- Routing in ASP.NET Web API和配置文件的设定读取
Routing Tables In ASP.NET Web API, a controller is a class that handles HTTP requests. The public me ...
- Routing in ASP.NET Web API
Why is HttpGet required only for some actions? https://stackoverflow.com/questions/28068868/why-is-h ...
- 如何让ASP.NET Web API的Action方法在希望的Culture下执行
在今天编辑推荐的<Hello Web API系列教程--Web API与国际化>一文中,作者通过自定义的HttpMessageHandler的方式根据请求的Accep-Language报头 ...
- ASP.NET Web API是如何根据请求选择Action的?[下篇]
ASP.NET Web API是如何根据请求选择Action的?[下篇] 再<上篇>中我们简单介绍了用于实现Action选择机制的HttpActionSelector,接下来我们来讨论本章 ...
- ASP.NET Web API是如何根据请求选择Action的?[上篇]
ASP.NET Web API是如何根据请求选择Action的?[上篇] Web API的调用请求总是针对定义在某个HttpController中的某个Action方法,请求响应的内容来源于调用目标A ...
随机推荐
- 面试题思考:Stack和Heap的区别
堆栈的概念: 堆栈是两种数据结构.堆栈都是一种数据项按序排列的数据结构,只能在一端(称为栈顶(top))对数据项进行插入和删除.在单片机应用中,堆栈是个特殊的存储区,主要功能是暂时存放数据和地址,通常 ...
- Kotlin教程——史上最全面、最详细的学习教程,持续更新中....
关于这个系列教程,我是从最基础的开发环境搭建到项目进阶到后面的项目开发这个过程来写的.我一直秉承从实际项目开发以及源码解析的角度去写好这个教程,并让从未接触过编程的朋友能学好kotlin这门语言.所以 ...
- Linq to Entity 多条件 OR查询
技术背景:框架MVC,linq to Entity 需要一定的lambda书写能力 问题:在简单的orm中完成一些简单的增删查改是通过where insert delete update 完成的,但是 ...
- 【BZOJ4145】[AMPPZ2014]The Prices 状压DP
[BZOJ4145][AMPPZ2014]The Prices Description 你要购买m种物品各一件,一共有n家商店,你到第i家商店的路费为d[i],在第i家商店购买第j种物品的费用为c[i ...
- fnt 图字原理
摘自:http://blog.csdn.net/wzq9706/article/details/8188256 首先要介绍一下,图字是怎么来的?其实这个很早很早了,记得80后在95年开始玩DOS下的仙 ...
- python单线程解决并发
1.单线程解决并发 方式一 import socket import select # 百度创建连接:非阻塞 client1 = socket.socket() client1.setblocking ...
- SSD(Single Shot MultiBox Detector)二读paper
SSD KeyWords:Real-time Object Detection; Convolutional Neural Network Introduction 目前最尖端(State-of-ar ...
- pandas(二)函数应用和映射
NumPy的ufuncs也可以操作pandas对象 >>> frame one two three four a 0 1 2 3 b 4 5 6 7 c 8 9 10 11 d 12 ...
- matlab循环保存dat文件
将数据保存为dat文件 这里有两种方法,第一种是: save filename dataname; 这种方法书写简单,但是功能也很简单.这里的filename就是死的filenam,即filename ...
- Flume日志收集 总结
Flume是一个分布式.可靠.和高可用的海量日志聚合的系统,支持在系统中定制各类数据发送方,用于收集数据: 同时,Flume提供对数据进行简单处理,并写到各种数据接受方(可定制)的能力. (1) 可靠 ...