Cleaning Up Your Controllers

So far, we have been adding attributes to our methods as we go along for each specific use case. However, now our controller is rather unorganized and full of commented out attributes. We can use a couple tips and tricks from attribute routing to clean this controller up.

Once you have written several action methods within a class, you may notice some similar behavior. You may also want to expand upon the behavior that different action methods can make use of. So far, we have been adding multiple different [Route("path")] attributes to each method to get every method to respond to a path that starts with localhost:5001/helloworld. We also want to use the Welcome() method to respond to GET requests and POST requests, not just one or the other. Time to DRY our code!

Class-Level Attributes

In addition to adding attributes above action methods, we can also add attributes for routing above the class. When we do so, we are designating class-wide behavior. In HelloController, we want every action method to respond to requests at paths that start with localhost:5001/helloworld. We can use [Route("path")] once above the class to designate that every path for each action method needs to start with /helloworld.

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   [Route("/helloworld")]
    public class HelloController : Controller
    {
        // action methods here
    }

Now that we have added that [Route("/helloworld")] above the class, we can start to modify the attributes we placed above the Index() method.

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   [HttpGet]
   public IActionResult Index()
   {
      string html = "<form method='post' action='/helloworld/welcome'>" +
            "<input type='text' name='name' />" +
            "<input type='submit' value='Greet Me!' />" +
            "</form>";

      return Content(html, "text/html");
   }

Since we want to map Index() to the path localhost:5001/helloworld, we removed the [Route("/helloworld")] attribute above the method. If we hadn’t, we would have inadvertently mapped the Index() method to the path, localhost:5001/helloworld/helloworld. We want to leave the [HttpGet] attribute above the Index() method so we can still specify that Index() responds to GET requests.

Now that just leaves us the Welcome() method!

One Method, Two Request Types

When we modified the Welcome() method to respond to a POST request, we commented out the attributes that we added when we were working with route parameters. With attributes, we can DRY our code and create one method that can respond to two different request types at two different routes. Before we begin, we should note that we can add route info directly to [HttpGet] and [HttpPost].

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   [HttpPost("welcome")]
   public IActionResult Welcome(string name = "World")
   {
      return Content("<h1>Welcome to my app, " + name + "!</h1>", "text/html");
   }

On line 1, we modified the [HttpPost] attribute to include the end of our path. Now Welcome() still responds to POST requests at localhost:5001/helloworld/welcome. However, this is just the beginning of us DRYing our code.

We also want Welcome() to respond to GET requests. We can modify an [HttpGet] attribute to do so.

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   [HttpGet("welcome/{name?}")]
   [HttpPost("welcome")]
   public IActionResult Welcome(string name = "World")
   {
      return Content("<h1>Welcome to my app, " + name + "!</h1>", "text/html");
   }

We added a different path to the [HttpGet] attribute on line 1. Now Welcome() can respond to GET requests at localhost:5001/helloworld/welcome, localhost:5001/helloworld/welcome?name=Tillie, and localhost:5001/helloworld/welcome/Tille. Welcome() can also still respond to the POST request at localhost:5001/helloworld/welcome upon submission of the form.

Now when we run our code, our app will still have the same functionalities, but now we have a more refined and organized code base!

Check Your Understanding