Controllers basics

Controllers basics

Simplify.Web has 6 types of controllers base classes:

Version 2 controllers

• Controller2 - general controller, processes HTTP request;
• Controller2<T> - the same as Controller2 class, but can get view model from HTTP request (T - is a type of view model);

Version 1 controllers

• Controller - general controller, processes HTTP request;
• AsyncController - the same as Controller class, but can process request asynchronously (can contain await operations and return Task);
• Controller<T> - the same as Controller class, but can get view model from HTTP request (T - is a type of view model);
• AsyncController<T> - the same as Controller<T> but can process request asynchronously.

The common controller structure for v1 and v2

• User created controller must be derived from one of the controller base classes specified above;
• Should contain Invoke method (executes on request process);
• Classes derived from ControllerResponse can do some actions, for example:
  • Put template data to DataCollector (main class for page HTML data collection);
  • Return some JSON data using Json response;
  • Redirect client to another page.
• If a controller does not have any attributes, then it will run on each HTTP request;
• To set controller for handling only specific action and request type you can use controller attributes from Simplify.Web.Attributes namespace.

Here is the list, description and examples of available controller responses.

Here is the list, description and examples of available controller attributes.

The specific controller v1 structure

• Should return instance of any class derived from ControllerResponse class or return null if there is no controller response to return;

The specific controller v2 structure

• Can have return type of void, Task, ControllerResponse or Task<ControllerResponse>;
• If it has void return type, then it means that controller is synchronous and don't need to return controller response;
• If it has Task return type, then it means that controller is asynchronous and don't need to return controller response;
• If it has ControllerResponse return type, then it means that controller wants to return controller response and it is synchronous;
• If it has Task<ControllerResponse> return type, then it means that controller wants to return controller response and it is asynchronous;

V2 controllers examples

Example of the controller which serializes collection to a JSON string thereby skipping backend page generation

[Get("api/weatherTypes")]
public class SampleDataController : Controller2
{
    private static readonly string[] Summaries =
    {
        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

    public ControllerResponse Invoke()
    {
        try
        {
            return Json(items);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);

            return StatusCode(500);
        }
    }
}

Example of the controller which deletes user via users service

[Delete("api/v1/users/{id}")]
public class SampleDataController(IUsersService service) : Controller2
{
    public async Task<ControllerResponse> Invoke(int id)
    {
        await service.DeleteAsync(id);

        return StatusCode(204);
    }
}

Example of the controller which loads a Navbar.tpl template file and puts it to the DataCollector Navbar variable

public class NavbarController :Controller2
{
    public ControllerResponse Invoke() =>
        return InlineTpl("Navbar", TemplateFactory.Load("Navbar"));
}

V1 controllers examples

Example of the controller which serializes collection to a JSON string thereby skipping backend page generation

[Get("api/weatherTypes")]
public class SampleDataController : Controller
{
    private static readonly string[] Summaries =
    {
        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

    public override ControllerResponse Invoke()
    {
        try
        {
            return Json(items);
        }
        catch (Exception e)
        {
            Console.WriteLine(e);

            return StatusCode(500);
        }
    }
}

Example of the controller which loads a Navbar.tpl template file and puts it to the DataCollector Navbar variable

public class NavbarController :Controller
{
    public override ControllerResponse Invoke() =>
        return InlineTpl("Navbar", TemplateFactory.Load("Navbar"));
}

Example of the v1 controller which loads an About.tpl template file and puts it to the DataCollector MainContent variable

This controller runs only on HTTP GET request with about action like: http://mysite.com/about

[Get("about")]
public class AboutController : Controller
{
    public override ControllerResponse Invoke() =>
        return StaticTpl("Static/About");
}

Example of v1 async controller

Async controllers must return Task<ControllerResponse> instead of just ControllerResponse

public class NavbarController : AsyncController
{
    public async override Task<ControllerResponse> Invoke() =>
        return InlineTpl("Navbar", await TemplateFactory.LoadAsync("Navbar"));
}

Accessing a view

To access a view from a controller you should use GetView<T>() method.

public class MyController : Controller
{
    public override ControllerResponse Invoke()
    {
        var view = GetView<LoginView>();
        ...
    }
}

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