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Getting Started
Your First App

Your First App

This page walks you through tutorial-01-helloworld, the smallest complete Nago application.

The code

Put the following into main.go of the module you created during installation:

// main denotes an executable go package. If you don't know, what that means, go through the Go Tour first.
package main

import (
	"go.wdy.de/nago/application"
	"go.wdy.de/nago/presentation/core"
	. "go.wdy.de/nago/presentation/ui"
	"go.wdy.de/nago/web/vuejs"
)

// the main function of the program, which is like the java public static void main.
func main() {
	// we use the applications package to bootstrap our configuration
	application.Configure(func(cfg *application.Configurator) {
		cfg.SetApplicationID("de.worldiety.tutorial_01")
		cfg.Serve(vuejs.Dist())

		cfg.RootView(".", func(wnd core.Window) core.View {
			return VStack(Text("hello world")).
				Frame(Frame{}.MatchScreen())
		})
	}).
		// don't forget to call the run method, which starts the entire thing and blocks until finished
		Run()
}

View on GitHub ↗ · run it with go run go.wdy.de/nago/example/cmd/tutorial-01-helloworld@latest

Configure

application.Configure creates the application and calls your function with an *application.Configurator. Everything an application consists of is registered here: its identity, the frontend, the pages and the systems you need. See Application and configurator.

Set the application ID

SetApplicationID gives the application a unique, reverse-DNS-like identifier such as com.example.myapp. Nago uses it for the name of the data directory, so do not change it once your application stores data.

Serve the frontend

cfg.Serve(vuejs.Dist()) serves the compiled Vue.js frontend which is embedded in the Nago module. Without it, the browser gets no user interface.

Register a root view

cfg.RootView(".", ...) registers the page for the path ., which is the start page at /. The factory gets the core.Window of the browser tab and returns the view tree to display: a VStack with a Text, whose Frame matches the screen so that the text is centered. Nago calls this factory again whenever the page must be rendered, see Views and State and rendering.

Run

Run starts the web server and blocks until the process receives SIGINT or SIGTERM, e.g. by Ctrl+C.

The tutorial dot-imports go.wdy.de/nago/presentation/ui, so you can write VStack instead of ui.VStack. Most tutorials do this; whether you do is a matter of taste.

Run it 

go mod tidy
go run .

Open http://localhost:3000:

Hello world

By default, the server listens on localhost port 3000. Set the environment variables HOST and PORT to change this, e.g. PORT=8080 go run .. All settings are described in Configuration and deployment.

Where your data lives

Even hello world gets a private data directory. Unless configured otherwise, it is ~/.nago/<application ID>, here ~/.nago/de.worldiety.tutorial_01. All stores, files and keys of your application land there. Delete the directory to start from scratch. See Persistence for its layout.

Next steps

Installation