WEBAPI Learning Notes API and return type (Action Results in Web API 2)

This article is mainly translated from English, the original address http://www.asp.net/web-api/overview/getting-started-with-aspnet-web-api/action-results

This article focuses on how ASP. NET Webapi translates API return values to HTTP response messages.

A WEBAPI can return one of the following types:

1. void

2,httpresponsemessage

　　　　3,Ihttpactionresult

　　　　4. Other types

More of the different return types above, WEBAPI uses different mechanisms to create HTTP response messages.

How

Return Type	Web API creates the response
void	Return Empty 204 (No Content)
Httpresponsemessage	Convert directly to an HTTP response message.
Ihttpactionresult	Call Executeasync to create a httpresponsemessage, then convert to an HTTP response message.
Other type	Write the serialized return value into the response body; Return (OK).

The first side introduces four types of details.

void

If the API function return type is VOID,WEBAPI, a null HTTP response message with a status code of 204 will be returned, as in the following code:

 Public class valuescontroller:apicontroller{    publicvoid  Post ()    {    }}

HTTP Response:

http/1.1204  No contentserver:microsoft-iis/8.0  the from:+ GMT

Httpresponsemessage

If the Httpresponsemessage type is returned, the Web API converts the return value directly into an HTTP response message and populates the response with the Httpresponsemessage Property object. As follows:

 Public classvaluescontroller:apicontroller{ Publichttpresponsemessage Get () {httpresponsemessage response= Request.createresponse (Httpstatuscode.ok,"value"); Response. Content=NewStringcontent ("Hello", Encoding.unicode); Response. Headers.cachecontrol=NewCachecontrolheadervalue () {MaxAge= Timespan.fromminutes ( -)        }; returnresponse; }}

HTTP response:

http/1.1  OKCache-control:max-age=1200Content10  Content-type:text/plain; charset=utf-server:microsoft-iis/8.0 : £º  Gmthello

The above code creates a Httpresponsemessage type variable, directly using the value originally returned to generate the Httpresponsemessage variable. The variable is then returned.

Ihttpactionresult

The Ihttpactionresult interface is defined in Webapi 2. It defines a httpresponsemessage factory. It defines a simple function Executeasync, which is used to asynchronously Httpresponsemessage

 Public Interface ihttpactionresult{    Task<HttpResponseMessage>

If the API returns IHTTPACTIONRESULT,WEBAPI call the executeasync function to create a httpresponsemessage. The httpresponsemessage is then converted to an HTTP response message.

Public class valuescontroller  : apicontroller{ public ihttpactionresult< Span class= "PLN" > get ()  {  return newtextresult ( "hello" , Span class= "Typ" >request);  }}       /span>                

HTTP response:

http/1.1  okcontent5Content-type:text/plain; charset=utf-8server:microsoft-iis/8.008 :+:  Gmthello

Other types

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WEBAPI Learning Notes API and return type (Action Results in Web API 2)