Views

Invirt's view layer is a thin convention over http4k templating. A response that renders a Pebble template is either produced from an InvirtView instance, or directly via renderTemplate(request, "template").

InvirtView

InvirtView is the base class for view models. It associates a model class with a template name so the handler doesn't have to repeat the template path each time.

open class InvirtView(val template: String)

The .peb extension is optional in the template name. Both InvirtView("users/list") and InvirtView("users/list.peb") resolve to the same template.

data class ListUsersResponse(
    val users: List<User>
) : InvirtView("users/list") // Points to webapp/views/users/list.peb

val handler = routes(
    "/users/list" GET { request ->
        ListUsersResponse(users).ok(request)
    },
    "/users/create" POST { request ->
        CreateUserResponse(user).status(request, Status.ACCEPTED)
    }
)

The request argument is required because Invirt makes the current Request available to the template (see Current request).

Response helpers

Function	Description
InvirtView.ok(request)	Renders the view with HTTP 200
InvirtView.status(request, status)	Renders the view with the given status
renderTemplate(request, template, model?)	Renders an arbitrary template without an InvirtView

"/" GET { request ->
    renderTemplate(request, "index")
}

"/profile" GET { request ->
    renderTemplate(request, "profile", mapOf("name" to "John"))
}

Error responses

Validation errors are returned as a special kind of view response that exposes the failed model and the ValidationErrors to the Pebble template (see Form validation).

fun errorResponse(
    request: Request,
    errors: ValidationErrors,
    template: String,
    model: Any? = null,
    status: Status = Status.UNPROCESSABLE_ENTITY
): Response

"/signup" POST { request ->
    request.toForm<SignupForm>()
        .validate()
        .map {
            success { form -> httpSeeOther("/signup/success") }
            error { form, errors -> errorResponse(request, errors, "signup", form) }
        }
}

For convenience, an InvirtView can also be rendered as an error response directly:

SignupView().asErrorResponse(request, errors)

A short-form overload is available for one-off field errors without a backing model:

errorResponse(request, "signup", "email" to "Email already in use")