ASP.NET Core: [FromQuery] usage and URL format

superninja picture superninja · Apr 9, 2018 · Viewed 53.6k times · Source

I am trying to use [FromQuery] in my web api and I am not sure how to use it.

Here's the GetAllBooks() method in the controller:

 [HttpGet]
 [Route("api/v1/ShelfID/{shelfID}/BookCollection")]
 public async Task<IActionResult> GetAllBooks(string shelfID, [FromQuery] Book bookinfo)
            {
               //do something
            }

Here's the Book model class:

 public class Book
    {
        public string ID{ get; set; }
        public string Name{ get; set; }
        public string Author { get; set; }
        public string PublishDate { get; set; }
    }

I am confused about whether it is the correct way to use [FromQuery]. I thought the URL is

https://localhost:xxxxx/api/v1/ShelfID/{shelfID}/BookCollection/IActionResult?ID="123"&Name="HarryPotter"

But the break point is not hitting my controller method, so I was thinking maybe the URL is not correct. Any suggestions? Thanks!

Answer

Fred Kleuver picture Fred Kleuver · Apr 9, 2018

The name of the method and return type are completely ignored when you define your route explicitly via attributes like that. IActionResult shouldn't be there.

The correct URL would be: https://localhost:xxxxx/api/v1/ShelfID/{shelfID}/BookCollection?ID="123"&Name="HarryPotter"

Furthermore, query string binding only works out of the box for primitive types (string, int, etc). To bind a class to a query string you'd need a custom modelbinder, which is quite involved.

It would be better to just explicitly declare the properties you want to pass in:

public async Task<IActionResult> GetAllBooks(string shelfID, [FromQuery] string ID, [FromQuery] string Name)