Controller & Action

Goku maps URLs to controllers that regiest to goku server. Controllers process incoming requests, handle user input and interactions, and execute appropriate application logic. A controller typically calls a separate view component to generate the HTML markup for the request.

ControllerBuilder

We build controller with ControllerBuilder

// a home controller builder
var cb *goku.ControllerBuilder = goku.Controller("home")
// add a "index" action to "home" controller for http get
cb.Get("index", func(ctx *goku.HttpContext) goku.ActionResulter {
    return ctx.Html("Hello World")
})

Use goku.Controller("controller-name") to get a controller builder. If the controller "controller-name" exist, it will just return the same controller builder.

Action

User interaction with goku MVC applications is organized around controllers and action methods. The controller defines action methods. Controllers can include as many action methods as needed.

When a user enters a URL into the browser, the MVC application uses routing rules to parse the URL and to determine the path of the controller. The controller then determines the appropriate action method to handle the request. By default, the URL of a request is treated as a sub-path that includes the controller name followed by the action name. For example, if a user enters the URL http://abc.com/Products/Categories, the sub-path is /Products/Categories. The default routing rule treats “Products” as the controller. It treats “Categories” as the name of the action. Therefore, the routing rule invokes the Categories action of the Products controller in order to process the request. If the URL ends with /Products/Detail/5, the default routing rule treats "Detail" as the name of the action, and the Detail action of the Products controller is invoked to process the request.

The following example shows a controller that has a HelloWorld action for http GET method.

var _ = goku.Controller("my").
    Action("get", "HelloWorld", func(ctx *goku.HttpContext) goku.ActionResulter {
        return ctx.Html("Hello World")
    })

ControllerBuilder has some helper method: Get, Post, Put. So you can do it the same by this code:

var _ = goku.Controller("my").
    Get("HelloWorld", func(ctx *goku.HttpContext) goku.ActionResulter {
        return ctx.Html("Hello World")
    })

If you set http method to all, the action will match all http method, but Priority is low.
For example:

var _ = goku.Controller("user").
    // action 1
    Post("edit", func(ctx *goku.HttpContext) goku.ActionResulter {
        return ctx.View(nil)
    }).
    // action 2
    Action("all", "edit", func(ctx *goku.HttpContext) goku.ActionResulter {
        return ctx.View(nil)
    })

A Http POST /user/edit request will process by Post("edit", ...),
but a Http GET /user/edit request will process by Action("all", "edit", ...).

ActionResult Return Type

Action methods return an instance of a struct that implement the ActionResulter interface. There are different action result types, depending on the task that the action method is performing. For example, the most common action is to call the HttpContext.View method. The View method returns an instance of the ViewResult struct, which is implement the ActionResulter interface.

The following table shows the built-in action result types and the action helper methods that return them.

Custom ActionResult

To implement your own action result, you just need to implement the ActionResulter interface, and return it in the action.