Dealing with multiple GET actions Web API

Question

I am new to WEB API and trying to set up routing for multiple GET actions.

Controller Code

// Get api/values
public IEnumerable<tblUser> Get()
{
    //whatever 
}

// Get api/values/action
[ActionName("GetByQue")]
public IEnumerable<tblQue> GetQue()
{
    //whatever 
}

// Get api/values/action
[ActionName("GetUserScore")]
public IEnumerable<tblScore> GetScore(string user)
{
   //whatever 
}

Config

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

config.Routes.MapHttpRoute(
    name: "DefaultActionApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { action = "GetByQue" }
);

config.Routes.MapHttpRoute(
    name: "DefaultStringApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { action = "GetUserScore" }
);

When I try with http://localhost:54118/api/remote/GetByQue URL getting this error

{
  "Message": "The request is invalid.",
  "MessageDetail": "The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'System.String Get(Int32)' in 'HydTechiesApi.Controllers.HydTechiesApiController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter."
}

is my routing wrong? Any help would be valuable as I am not able to find a solution.

Answer 1

1. You made a couple of mistakes in your route. As your example code below:

     config.Routes.MapHttpRoute(
     name: "DefaultActionApi",
     routeTemplate: "api/{controller}/{id}",
     defaults: new { action = "GetByQue" });
     //url:   http://localhost:54118/api/remote/GetByQue 
   

(1). routeTemplate: "api/{controller}/{id}". you specify your route has an id and it is not Optional. So your URL must have id. That's what your error showed.you can handle with the issue like below:

   defaults: new { id = RouteParameter.Optional }

(2). defaults: new { action = "GetByQue" }); you did not say any thing about action in your routeTemplate. your defaults about action, which does not have any meaning.

(3). From your route, your URL should look like http://localhost:54118/api/remote/5 , you should not get mutiple get method by your route.

2. There are some solutions, which you may use:

(1). change route like below:

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

please add [HttpGet] in each method just in cause.

     [HttpGet]
     public IEnumerable<tblUser> Get()
      {......}

     [HttpGet]
     [ActionName("GetByQue")]
     public IEnumerable<tblQue> GetQue()
     {......}

     [HttpGet]
     [ActionName("GetUserScore")]
       public IEnumerable<tblScore> GetScore(string user)
       {......}

Now you can use URL like http://localhost:54118/api/remote/GetByQue

Very Useful Tips: Using [Route("")] tag to specify parameters **You also have to change Route like above (1)

in Controller, please specify request method to make sure the get method

    [HttpGet]
    [ActionName("GetUserScore")]
    [Route("api/remote/GetScore/{user}")]
     public IEnumerable<tblScore> GetScore(string user)
    {.....}
    //URL: http://localhost:54118/api/remote/GetScore/user

Answer 2

You should add {action} to routeTemplate instead of {id} in the second configuration

config.Routes.MapHttpRoute(
    name: "DefaultActionApi",
    routeTemplate: "api/{controller}/{action}",
    defaults: new { action = "GetByQue" }
);

also you can try to use route attribure on action :

[ActionName("GetByQue")]
[Route("api/remote/GetByQue")]
public IEnumerable<tblQue> GetQue()
{
    //whatever 
}

or change order(the second configuration and first configuration) of configuration in WebApiConfig.cs