為什么相同的POST請求在POSTMAN中起作用，但在瀏覽器AJAX中卻不起作用（找不到404）？

Question

我已經使用以下POST方法創建了ASP.NET WebAPI：

[HttpPost, Route("")]
public IHttpActionResult Post([FromBody] StudentDto student)
{
    if (!ModelState.IsValid)
        return BadRequest(ModelState);

    var maxId = conrollerStudents.Max(x => x.ID);
    student.ID = ++maxId;
    conrollerStudents.Add(student);

    InsertStudentIntoDatabase(student);

    return CreatedAtRoute("GetStudent", new { id = student.ID }, student);
}

WebAPI的配置：

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.EnableCors();

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

此API方法僅在POSTMAN中有效，在POSTMAN中，我因POST請求而得到201。 當我使用以下代碼（由POSTMAN自動生成）將請求移至JavaScript-Jquery-AJAX時。 我收到以下錯誤消息：

{
    "Message":"No HTTP resource was found that matches the request URI 'http://localhost:59523/api/students'.",
    "MessageDetail":"No action was found on the controller 'Students' that matches the request."
}

這是自動生成的JavaScript-Jquery-AJAX代碼，碰巧不起作用：

// ...
var settings = {
    "async": true,
    "crossDomain": true,
    "url": "http://localhost:59523/api/students",
    "method": "POST",
    "headers": {
        "content-type": "application/json"
    },
    "processData": false,
    "data": "{\n  \"FirstName\": \"Sample\",\n  \"LastName\": \"Sample\",\n  \"City\": \"Sample\",\n  \"ListOfCourses\": []\n}"
};

$.ajax(settings).done(function (response) {
    console.log(response);
});
// ...

知道為什么會這樣嗎？

Answer 1

似乎您希望該方法成為該控制器上的默認操作，請嘗試將默認操作設置為Index並將您的方法重命名為Index。

defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }

Answer 2

此問題與錯誤的WebAPI配置文件Web.config有關 。 我將system.webServer部分更改為：

<system.webServer>
  <handlers>
    <remove name="ExtensionlessUrlHandler-Integrated-4.0"/>
    <remove name="TRACEVerbHandler"/>
    <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH" modules="IsapiModule" 
          scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />      
    <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH" type="System.Web.Handlers.TransferRequestHandler" 
          preCondition="integratedMode,runtimeVersionv4.0" />
  </handlers>
  <httpProtocol>
    <customHeaders>
      <add name="Access-Control-Allow-Origin" value="*"/>
      <add name="Access-Control-Allow-Headers" value="Content-Type"/>
      <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE, OPTIONS"/>
    </customHeaders>
  </httpProtocol>
</system.webServer>