Attribute routing cheat sheet for ASP.NET Core

Posted on: 22-10-2016 5 Comments

Below you can find typical and some not so typical routes being mapped on controller actions.

This is meant to be a cheat sheet that you can come back and refer to.

public class TestController : Controller
{
    // /hello
    [Route("/hello")]
    public IActionResult Hello()
        => Ok("Hello");

    // /hi only GET method
    [Route("/hi")]
    [HttpGet]
    public IActionResult Hi()
        => Ok("Hi");

    //Alternative for previous
    [HttpGet("/hi")]
    public IActionResult Hi()
        => Ok("Hi");
}

//Route prefix
[Route("test")]
public class TestController : Controller
{
    //You can have multiple routes on an action
    [Route("")] // /test
    [Route("hello")] // /test/hello
    public IActionResult Hello()
        => Ok("Hello");

    // Maps to both:
    // /test/hi, and:
    // /hi
    [Route("/hi")] // Overrides the prefix with /, you can also use ~/
    [Route("hi")]
    public IActionResult Hi()
        => Ok("Hi");

    // /test/greet/Joonas -> maps Joonas to the name parameter
    [Route("greet/{name}")]
    public IActionResult Greet(string name)
        => Ok($"Hello {name}!");

    //Parameters can be optional
    // /test/greetopt -> name == null
    // /test/greetopt/Joonas -> name == Joonas
    [Route("greetopt/{name?}")]
    public IActionResult GreetOptional(string name)
        => Ok(name == null ? "No name" : "Hi!");
}

// You can use [controller], [action], and [area] to create generic templates
[Route("[controller]/[action]")]
public class MyController : Controller
{
    // /my/info
    public IActionResult Info()
        => Ok("Info");

    // /my/i
    [Route("/[controller]/i")]
    public IActionResult Info2()
        => Ok("Info2");
}

[Route("users")]
public class SelectionController : Controller
{
    //You can use constraints to influence route selection
    //Do not use for validation!
    // /users/123
    [Route("{id:int}")]
    public IActionResult Int(int id)
        => Ok($"Looked up user id {id}");
    // /users/joonas
    [Route("{name:alpha}")]
    public IActionResult String(string name)
        => Ok($"User name {name}");
}

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