refactor: new (simpler) version of the sl library

cmd/build/main.go

@@ -8,7 +8,6 @@ import (
 	"phc/website/services/database"
 	"phc/website/services/server"
 	"phc/website/services/server/dev"
-	lista_utenti "phc/website/services/server/lista-utenti"
 	"phc/website/sl"
 )
 
@@ -17,23 +16,20 @@ func main() {
 
 	// sl.Inject[config.Interface](l, &config.EnvConfig{})
 
-	sl.InjectValue[config.Interface](l, &config.Custom{
-		ModeValue: "production",
-		HostValue: ":4000",
+	sl.InjectValue(l, config.Slot, &config.Config{
+		Mode: "production",
+		Host: ":4000",
 	})
 
-	sl.InjectValue[database.Database](l, &database.Memory{})
+	sl.InjectValue(l, database.Slot, database.Database(
+		&database.Memory{}),
+	)
 
-	sl.Inject(l, &dev.Dev{})
-	sl.Inject(l, &lista_utenti.ListaUtenti{})
-	sl.Inject(l, &server.Server{})
-
-	_, err := sl.Use[*server.Server](l)
-	if err != nil {
+	if _, err := server.Configure(l); err != nil {
 		log.Fatal(err)
 	}
 
-	dev, err := sl.Use[*dev.Dev](l)
+	dev, err := sl.Use(l, dev.Slot)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -48,4 +44,6 @@ func main() {
 	if err := enc.Encode(dev.HtmlRouteBindings); err != nil {
 		log.Fatal(err)
 	}
+
+	log.Printf(`generated "out/routes.json"`)
 }

cmd/server/main.go

@@ -6,22 +6,18 @@ import (
 	"phc/website/services/config"
 	"phc/website/services/database"
 	"phc/website/services/server"
-	"phc/website/services/server/dev"
-	lista_utenti "phc/website/services/server/lista-utenti"
 	"phc/website/sl"
 )
 
 func main() {
 	l := sl.New()
 
-	// sl.Inject[config.Interface](l, &config.EnvConfig{})
-
-	config := sl.InjectValue[config.Interface](l, &config.Custom{
-		ModeValue: "production",
-		HostValue: ":4000",
+	cfg := sl.InjectValue(l, config.Slot, &config.Config{
+		Mode: "production",
+		Host: ":4000",
 	})
 
-	sl.InjectValue[database.Database](l, &database.Memory{
+	sl.InjectValue[database.Database](l, database.Slot, &database.Memory{
 		Users: []model.User{
 			{
 				Id:          "claire",
@@ -38,14 +34,10 @@ func main() {
 		},
 	})
 
-	sl.Inject(l, &dev.Dev{})
-	sl.Inject(l, &lista_utenti.ListaUtenti{})
-	sl.Inject(l, &server.Server{})
-
-	server, err := sl.Use[*server.Server](l)
+	srv, err := server.Configure(l)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	log.Fatal(server.Router.Listen(config.Host()))
+	log.Fatal(srv.Router.Listen(cfg.Host))
 }

services/config/config.go

@@ -6,47 +6,30 @@ import (
 	"github.com/joho/godotenv"
 )
 
-type Interface interface {
-	sl.Service
+var Slot = sl.NewSlot[*Config]()
 
-	Mode() string
-	Host() string
+type Config struct {
+	Mode string
+	Host string
 }
 
-type Custom struct {
-	ModeValue string
-	HostValue string
-}
-
-func (c Custom) Mode() string { return c.ModeValue }
-func (c Custom) Host() string { return c.HostValue }
-
-func (Custom) Initialize(l *sl.ServiceLocator) error {
-	return nil
-}
-
-type EnvConfig struct {
-	mode string
-	host string
-}
-
-func (c EnvConfig) Mode() string { return c.mode }
-func (c EnvConfig) Host() string { return c.host }
-
-func (c *EnvConfig) Initialize(l *sl.ServiceLocator) error {
+func Load(l *sl.ServiceLocator) (*Config, error) {
 	m, err := godotenv.Read(".env")
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	c.mode = "production"
+	mode := "production"
 	if v, ok := m["MODE"]; ok {
-		c.mode = v
+		mode = v
 	}
-	c.host = ":4000"
+	host := ":4000"
 	if v, ok := m["HOST"]; ok {
-		c.host = v
+		host = v
 	}
 
-	return nil
+	return &Config{
+		mode,
+		host,
+	}, nil
 }

services/database/database.go

@@ -6,9 +6,9 @@ import (
 	"phc/website/sl"
 )
 
-type Database interface {
-	sl.Service
+var Slot = sl.NewSlot[Database]()
 
+type Database interface {
 	CreateUser(user model.User) error
 	ReadUser(id string) (model.User, error)
 	ReadUsers() ([]model.User, error)
@@ -20,8 +20,6 @@ type Memory struct {
 	Users []model.User
 }
 
-func (m *Memory) Initialize(l *sl.ServiceLocator) error { return nil }
-
 func (m *Memory) CreateUser(user model.User) error {
 	m.Users = append(m.Users, user)
 	return nil

services/server/dev/dev.go

@@ -9,35 +9,39 @@ import (
 	"github.com/gofiber/fiber/v2"
 )
 
+var Slot = sl.NewSlot[*Dev]()
+
 type Dev struct {
 	HtmlRouteBindings map[string]string
 }
 
-func (m *Dev) Initialize(l *sl.ServiceLocator) error {
-	m.HtmlRouteBindings = map[string]string{}
+func New(l *sl.ServiceLocator) (*Dev, error) {
+	dev := &Dev{
+		map[string]string{},
+	}
 
-	router, err := sl.Use[*routes.Router](l)
+	router, err := sl.Use(l, routes.Api)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	router.Get("/api/dev/routes", func(c *fiber.Ctx) error {
-		return c.JSON(m.HtmlRouteBindings)
+	router.Get("/dev/routes", func(c *fiber.Ctx) error {
+		return c.JSON(dev.HtmlRouteBindings)
 	})
 
-	return nil
+	return dev, nil
 }
 
 // UseVitePage this hook will link the provided "mountPoint" to the "frontendHtml" page
-func UseVitePage[T any](l *sl.ServiceLocator, mountPoint, frontendHtml string) func(c *fiber.Ctx) error {
+func UseVitePage(l *sl.ServiceLocator, mountPoint, frontendHtml string) func(c *fiber.Ctx) error {
 	log.Printf(`registering vite route %q for %q`, frontendHtml, mountPoint)
 
-	dev, err := sl.Use[*Dev](l)
+	dev, err := sl.Use(l, Slot)
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	dev.HtmlRouteBindings[mountPoint] = path.Join("./frontend/", frontendHtml)
+	dev.HtmlRouteBindings[mountPoint] = frontendHtml
 
 	return func(c *fiber.Ctx) error {
 		return c.SendFile(path.Join("./out/frontend/", frontendHtml))

services/server/lista-utenti/lista-utenti.go

@@ -9,24 +9,22 @@ import (
 	"github.com/gofiber/fiber/v2"
 )
 
-type ListaUtenti struct{}
-
-func (s *ListaUtenti) Initialize(l *sl.ServiceLocator) error {
-
-	db, err := sl.Use[database.Database](l)
+func Configure(l *sl.ServiceLocator) error {
+	db, err := sl.Use(l, database.Slot)
 	if err != nil {
 		return err
 	}
 
-	router, err := sl.Use[*routes.Router](l)
+	r, err := sl.Use(l, routes.Root)
 	if err != nil {
 		return err
 	}
 
-	router.Get("/utenti",
-		dev.UseVitePage[ListaUtenti](l, "/utenti", "pages/lista-utenti/index.html"),
+	r.Get("/utenti",
+		dev.UseVitePage(l, "/utenti", "pages/lista-utenti/index.html"),
 	)
-	router.Get("/api/lista-utenti", func(c *fiber.Ctx) error {
+
+	r.Get("/api/lista-utenti", func(c *fiber.Ctx) error {
 		users, err := db.ReadUsers()
 		if err != nil {
 			return err

services/server/lista-utenti/lista-utenti_test.go

@@ -8,8 +8,6 @@ import (
 	"net/http"
 	"phc/website/model"
 	"phc/website/services/database"
-	"phc/website/services/server/dev"
-	lista_utenti "phc/website/services/server/lista-utenti"
 	"phc/website/services/server/routes"
 	"phc/website/sl"
 	"testing"
@@ -22,7 +20,7 @@ import (
 func Test1(t *testing.T) {
 	l := sl.New()
 
-	sl.InjectValue[database.Database](l, &database.Memory{
+	sl.InjectValue[database.Database](l, database.Slot, &database.Memory{
 		Users: []model.User{
 			{
 				Id:          "claire",
@@ -39,11 +37,8 @@ func Test1(t *testing.T) {
 		},
 	})
 
-	sl.Inject(l, &dev.Dev{})
-	sl.Inject(l, &lista_utenti.ListaUtenti{})
-
 	r := fiber.New()
-	sl.InjectValue(l, routes.NewRouter(r))
+	sl.InjectValue(l, routes.Root, fiber.Router(r))
 
 	req, err := http.NewRequest("GET", "http://localhost:4000/api/lista-utenti", nil)
 	if err != nil {

services/server/routes/routes.go

@@ -6,10 +6,6 @@ import (
 	"github.com/gofiber/fiber/v2"
 )
 
-func NewRouter(r fiber.Router) *Router {
-	return &Router{r}
-}
+var Root = sl.NewSlot[fiber.Router]()
 
-type Router struct{ fiber.Router }
-
-func (s *Router) Initialize(l *sl.ServiceLocator) error { return nil }
+var Api = sl.NewSlot[fiber.Router]()

services/server/server.go

@@ -11,16 +11,21 @@ import (
 
 type Server struct{ Router *fiber.App }
 
-func (s *Server) Initialize(l *sl.ServiceLocator) error {
-	s.Router = fiber.New(fiber.Config{})
-	sl.InjectValue(l, routes.NewRouter(s.Router))
+func Configure(l *sl.ServiceLocator) (*Server, error) {
+	r := fiber.New(fiber.Config{})
 
-	if _, err := sl.Use[*dev.Dev](l); err != nil {
-		return err
+	sl.InjectValue(l, routes.Root, r.Group("/"))
+	sl.InjectValue(l, routes.Api, r.Group("/api"))
+
+	devServerInterop, err := dev.New(l)
+	if err != nil {
+		return nil, err
 	}
-	if _, err := sl.Use[*lista_utenti.ListaUtenti](l); err != nil {
-		return err
+	sl.InjectValue(l, dev.Slot, devServerInterop)
+
+	if err := lista_utenti.Configure(l); err != nil {
+		return nil, err
 	}
 
-	return nil
+	return &Server{r}, nil
 }

sl/sl.go

@@ -5,69 +5,146 @@ import (
 	"log"
 )
 
-type provider struct {
-	initialized bool
-	service     Service
-}
+type SlotKey[T any] *struct{}
 
-type ServiceLocator struct {
-	providers map[string]*provider
-	hooks     map[string][]Service
+func NewSlot[T any]() SlotKey[T] {
+	return SlotKey[T](new(struct{}))
 }
 
-type Service interface {
-	Initialize(l *ServiceLocator) error
+type slot struct {
+	createFunc func(*ServiceLocator) (any, error)
+	created    bool
+	value      any
+
+	typ string
 }
 
-func New() *ServiceLocator {
-	return &ServiceLocator{
-		providers: map[string]*provider{},
-		hooks:     map[string][]Service{},
+func (s *slot) checkInitialized(l *ServiceLocator) error {
+	if !s.created {
+		v, err := s.createFunc(l)
+		if err != nil {
+			return err
+		}
+
+		log.Printf(`initialized lazy value of type %T for slot of type %s`, v, s.typ)
+
+		s.value = v
 	}
-}
 
-func getTypeName[T any]() string {
-	var v T
-	return fmt.Sprintf(`%T`, &v)[1:]
+	return nil
 }
 
-// Inject will set the implementation for "S" to "value" (the service will be initialized when needed after all of its dependencies)
-func Inject[S Service](l *ServiceLocator, value S) {
-	key := getTypeName[S]()
-	log.Printf(`injecting value of type %T for interface %s`, value, key)
+type ServiceLocator struct {
+	providers map[any]*slot
+}
 
-	l.providers[key] = &provider{false, value}
+func New() *ServiceLocator {
+	return &ServiceLocator{
+		providers: map[any]*slot{},
+	}
 }
 
-// InjectValue will set the implementation for "S" to "value" and mark this service as already initialized (as this is just a constant)
-func InjectValue[S Service](l *ServiceLocator, value S) S {
-	key := getTypeName[S]()
-	log.Printf(`injecting value of type %T for interface %s`, value, key)
+func InjectValue[T any](l *ServiceLocator, slotKey SlotKey[T], value T) T {
+	log.Printf(`injected value of type %T for slot of type %s`, value, getTypeName[T]())
 
-	l.providers[key] = &provider{true, value}
+	l.providers[slotKey] = &slot{nil, true, value, getTypeName[T]()}
 	return value
 }
 
-// Use will retrive from the service locator the implementation set for the type "T" and initialize the service if yet to be initialized
-func Use[T Service](l *ServiceLocator) (T, error) {
-	provider, ok := l.providers[getTypeName[T]()]
-	if !ok {
-		var zero T
-		return zero, fmt.Errorf(`no injected value for type "%T"`, zero)
+func InjectLazy[T any](l *ServiceLocator, slotKey SlotKey[T], createFunc func(*ServiceLocator) (T, error)) {
+	log.Printf(`injected lazy for slot of type %s`, getTypeName[T]())
+
+	l.providers[slotKey] = &slot{
+		createFunc: func(l *ServiceLocator) (any, error) {
+			return createFunc(l)
+		},
+		created: false,
+		value:   nil,
+		typ:     getTypeName[T](),
 	}
+}
+
+func Use[T any](l *ServiceLocator, slotKey SlotKey[T]) (T, error) {
+	var zero T
 
-	if provider.initialized {
-		service := provider.service.(T)
-		return service, nil
+	slot, ok := l.providers[slotKey]
+	if !ok {
+		return zero, fmt.Errorf(`no injected value for type %s`, getTypeName[T]())
 	}
 
-	log.Printf(`initializing %T`, provider.service)
-	if err := provider.service.Initialize(l); err != nil {
-		var zero T
+	err := slot.checkInitialized(l)
+	if err != nil {
 		return zero, err
 	}
 
-	provider.initialized = true
-	service := provider.service.(T)
-	return service, nil
+	v := slot.value.(T)
+
+	log.Printf(`using slot of type %s with value of type %T`, getTypeName[T](), v)
+	return v, nil
+}
+
+// // Require forces the initialization of a slot
+// func Require[T any](l *ServiceLocator, slotKey SlotKey[T]) error {
+// 	var zero T
+
+// 	slot, ok := l.providers[slotKey]
+// 	if !ok {
+// 		return fmt.Errorf(`no injected value for type %T`, zero)
+// 	}
+
+// 	return slot.checkInitialized(l)
+// }
+
+// // MustRequire forces the initialization of a slot or panics if the slot is missing
+// func MustRequire[T any](l *ServiceLocator, slotKey SlotKey[T]) {
+// 	err := Require(l, slotKey)
+// 	if err != nil {
+// 		panic(err)
+// 	}
+// }
+
+// // Inject will set the implementation for "S" to "value" (the service will be initialized when needed after all of its dependencies)
+// func Inject[S Service](l *Context, value S) {
+// 	key := getTypeName[S]()
+// 	log.Printf(`injecting value of type %T for interface %s`, value, key)
+
+// 	l.providers[key] = &provider{false, nil, value}
+// }
+
+// // InjectValue will set the implementation for "S" to "value" and mark this service as already initialized (as this is just a constant)
+// func InjectValue[S Service](l *Context, value S) S {
+// 	key := getTypeName[S]()
+// 	log.Printf(`injecting value of type %T for interface %s`, value, key)
+
+// 	l.providers[key] = &provider{true, nil, value}
+// 	return value
+// }
+
+// // Use will retrive from the service locator the implementation set for the type "T" and initialize the service if yet to be initialized
+// func Use[T Service](l *Context) (T, error) {
+// 	provider, ok := l.providers[getTypeName[T]()]
+// 	if !ok {
+// 		var zero T
+// 		return zero, fmt.Errorf(`no injected value for type "%T"`, zero)
+// 	}
+
+// 	if provider.initialized {
+// 		service := provider.service.(T)
+// 		return service, nil
+// 	}
+
+// 	log.Printf(`initializing %T`, provider.service)
+// 	if err := provider.service.Initialize(l); err != nil {
+// 		var zero T
+// 		return zero, err
+// 	}
+
+// 	provider.initialized = true
+// 	service := provider.service.(T)
+// 	return service, nil
+// }
+
+func getTypeName[T any]() string {
+	var zero T
+	return fmt.Sprintf(`%T`, &zero)[1:]
 }

vite.config.js

@@ -17,7 +17,6 @@ const retriveGoRoutes = {
 
         const routesReq = await fetch('http://127.0.0.1:4000/api/dev/routes')
         const routes = await routesReq.json()
-        console.dir(routes, { depth: null })
 
         return routes
     },
@@ -51,8 +50,8 @@ export default defineConfig(async config => {
                 configureServer(server) {
                     Object.entries(routes).forEach(([route, file]) => {
                         server.middlewares.use(route, async (req, res, next) => {
-                            let htmlPage = await readFile(resolve(__dirname, file), 'utf8')
-                            htmlPage = htmlPage.replace(/\.\//g, dirname(file) + '/')
+                            let htmlPage = await readFile(resolve(__dirname, './frontend/', file), 'utf8')
+                            htmlPage = htmlPage.replace(/\.\//g, '/' + dirname(file) + '/')
 
                             const url = file
                             const html = await server.transformIndexHtml(url, htmlPage)