Revert "Removes internal api package"

This reverts commit c65e239b68.

internal/api/api.go

@@ -0,0 +1,31 @@
+package api
+
+import (
+	"errors"
+	"os"
+
+	"github.com/gofiber/fiber/v2"
+	"github.com/gofiber/fiber/v2/middleware/keyauth"
+)
+
+func Setup(app *fiber.App) error {
+	apiKey := os.Getenv("API_KEY")
+
+	if apiKey == "" {
+		return errors.New("Could not read API_KEY from ENV file.")
+	}
+
+	api := app.Group("/api", keyauth.New(keyauth.Config{
+		SuccessHandler: successHandler,
+		ErrorHandler:   errHandler,
+		KeyLookup:      "header:x-api-key",
+		ContextKey:     "apiKey",
+		Validator:      apiKeyValidator(apiKey),
+	}))
+
+	v1 := api.Group("/v1")
+
+	v1.Get("/users", FetchAllUsersHandler)
+
+	return nil
+}

internal/api/auth.go

@@ -0,0 +1,56 @@
+package api
+
+import (
+	"crypto/sha256"
+	"crypto/subtle"
+	"regexp"
+	"strings"
+
+	"github.com/gofiber/fiber/v2"
+	"github.com/gofiber/fiber/v2/middleware/keyauth"
+)
+
+var (
+	apiKey        = "willbechanged"
+	protectedURLs = []*regexp.Regexp{
+		regexp.MustCompile("^/api$"),
+	}
+	errForbidden = &fiber.Error{
+		Code:    403,
+		Message: "API Key is missing or invalid",
+	}
+)
+
+func apiKeyValidator(apiKey string) func(*fiber.Ctx, string) (bool, error) {
+	return func(_ *fiber.Ctx, key string) (bool, error) {
+		hashedAPIKey := sha256.Sum256([]byte(apiKey))
+		hashedKey := sha256.Sum256([]byte(key))
+
+		if subtle.ConstantTimeCompare(hashedAPIKey[:], hashedKey[:]) == 1 {
+			return true, nil
+		}
+
+		return false, keyauth.ErrMissingOrMalformedAPIKey
+	}
+}
+
+func protectedRoutesFilter(ctx *fiber.Ctx) bool {
+	originalURL := strings.ToLower(ctx.OriginalURL())
+
+	for _, pattern := range protectedURLs {
+		if pattern.MatchString(originalURL) {
+			return false
+		}
+	}
+	return true
+}
+
+func successHandler(ctx *fiber.Ctx) error {
+	return ctx.Next()
+}
+
+func errHandler(ctx *fiber.Ctx, err error) error {
+	ctx.Status(fiber.StatusForbidden)
+
+	return ctx.JSON(errForbidden)
+}

internal/api/users.go

@@ -0,0 +1,9 @@
+package api
+
+import (
+	"github.com/gofiber/fiber/v2"
+)
+
+func FetchAllUsersHandler(ctx *fiber.Ctx) error {
+	return ctx.JSON(&fiber.Map{"users": "none"})
+}