Rework project's structure

internal/di/handlers.go

@@ -0,0 +1,133 @@
+package di
+
+import (
+	"errors"
+	"net/http"
+	"strings"
+
+	"github.com/defval/di"
+	"github.com/etherlabsio/healthcheck/v2"
+	"github.com/gorilla/mux"
+	"github.com/spf13/viper"
+
+	. "github.com/elyby/chrly/internal/http"
+)
+
+var handlers = di.Options(
+	di.Provide(newHandlerFactory, di.As(new(http.Handler))),
+	di.Provide(newSkinsystemHandler, di.WithName("skinsystem")),
+	di.Provide(newApiHandler, di.WithName("api")),
+)
+
+func newHandlerFactory(
+	container *di.Container,
+	config *viper.Viper,
+	emitter Emitter,
+) (*mux.Router, error) {
+	enabledModules := config.GetStringSlice("modules")
+
+	// gorilla.mux has no native way to combine multiple routers.
+	// The hack used later in the code works for prefixes in addresses, but leads to misbehavior
+	// if you set an empty prefix. Since the main application should be mounted at the root prefix,
+	// we use it as the base router
+	var router *mux.Router
+	if hasValue(enabledModules, "skinsystem") {
+		if err := container.Resolve(&router, di.Name("skinsystem")); err != nil {
+			return nil, err
+		}
+	} else {
+		router = mux.NewRouter()
+	}
+
+	router.StrictSlash(true)
+	requestEventsMiddleware := CreateRequestEventsMiddleware(emitter, "skinsystem")
+	router.Use(requestEventsMiddleware)
+	// NotFoundHandler doesn't call for registered middlewares, so we must wrap it manually.
+	// See https://github.com/gorilla/mux/issues/416#issuecomment-600079279
+	router.NotFoundHandler = requestEventsMiddleware(http.HandlerFunc(NotFoundHandler))
+
+	if hasValue(enabledModules, "api") {
+		var apiRouter *mux.Router
+		if err := container.Resolve(&apiRouter, di.Name("api")); err != nil {
+			return nil, err
+		}
+
+		var authenticator Authenticator
+		if err := container.Resolve(&authenticator); err != nil {
+			return nil, err
+		}
+
+		apiRouter.Use(CreateAuthenticationMiddleware(authenticator))
+
+		mount(router, "/api", apiRouter)
+	}
+
+	err := container.Invoke(enableReporters)
+	if err != nil && !errors.Is(err, di.ErrTypeNotExists) {
+		return nil, err
+	}
+
+	// Resolve health checkers last, because all the services required by the application
+	// must first be initialized and each of them can publish its own checkers
+	var healthCheckers []*namedHealthChecker
+	if has, _ := container.Has(&healthCheckers); has {
+		if err := container.Resolve(&healthCheckers); err != nil {
+			return nil, err
+		}
+
+		checkersOptions := make([]healthcheck.Option, len(healthCheckers))
+		for i, checker := range healthCheckers {
+			checkersOptions[i] = healthcheck.WithChecker(checker.Name, checker.Checker)
+		}
+
+		router.Handle("/healthcheck", healthcheck.Handler(checkersOptions...)).Methods("GET")
+	}
+
+	return router, nil
+}
+
+func newSkinsystemHandler(
+	config *viper.Viper,
+	profilesProvider ProfilesProvider,
+	texturesSigner TexturesSigner,
+) *mux.Router {
+	config.SetDefault("textures.extra_param_name", "chrly")
+	config.SetDefault("textures.extra_param_value", "how do you tame a horse in Minecraft?")
+
+	return (&Skinsystem{
+		ProfilesProvider:        profilesProvider,
+		TexturesSigner:          texturesSigner,
+		TexturesExtraParamName:  config.GetString("textures.extra_param_name"),
+		TexturesExtraParamValue: config.GetString("textures.extra_param_value"),
+	}).Handler()
+}
+
+func newApiHandler(profilesManager ProfilesManager) *mux.Router {
+	return (&Api{
+		ProfilesManager: profilesManager,
+	}).Handler()
+}
+
+func hasValue(slice []string, needle string) bool {
+	for _, value := range slice {
+		if value == needle {
+			return true
+		}
+	}
+
+	return false
+}
+
+func mount(router *mux.Router, path string, handler http.Handler) {
+	router.PathPrefix(path).Handler(
+		http.StripPrefix(
+			strings.TrimSuffix(path, "/"),
+			handler,
+		),
+	)
+}
+
+type namedHealthChecker struct {
+	Name    string
+	Checker healthcheck.Checker
+}