Cleanup pt 1 (#4)

* Disable startup headers.

* Add banning / unbanning of specific user.

api.go

@@ -0,0 +1,133 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	fiber "github.com/gofiber/fiber/v2"
+	"github.com/gofrs/flock"
+	libpack_config "github.com/lukaszraczylo/graphql-monitoring-proxy/config"
+)
+
+var bannedUsersIDs map[string]string = make(map[string]string)
+
+func enableApi() {
+	if cfg.Server.EnableApi {
+		apiserver := fiber.New(fiber.Config{
+			DisableStartupMessage: true,
+			AppName:               fmt.Sprintf("GraphQL Monitoring Proxy - %s v%s", libpack_config.PKG_NAME, libpack_config.PKG_VERSION),
+		})
+
+		api := apiserver.Group("/api")
+		api.Post("/user-ban", apiBanUser)
+		api.Post("/user-unban", apiUnbanUser)
+
+		go periodicallyReloadBannedUsers()
+		err := apiserver.Listen(fmt.Sprintf(":%d", cfg.Server.ApiPort))
+		if err != nil {
+			cfg.Logger.Critical("Can't start the service", map[string]interface{}{"error": err.Error()})
+		}
+	}
+}
+
+func periodicallyReloadBannedUsers() {
+	for {
+		loadBannedUsers()
+		cfg.Logger.Debug("Banned users reloaded", map[string]interface{}{"users": bannedUsersIDs})
+		<-time.After(10 * time.Second)
+	}
+}
+
+func checkIfUserIsBanned(c *fiber.Ctx, userID string) bool {
+	_, found := bannedUsersIDs[userID]
+	cfg.Logger.Debug("Checking if user is banned", map[string]interface{}{"user_id": userID, "found": found})
+	if found {
+		cfg.Logger.Info("User is banned", map[string]interface{}{"user_id": userID})
+		c.Status(403).SendString("User is banned")
+	}
+	return found
+}
+
+type apiBanUserRequest struct {
+	UserID string `json:"user_id"`
+	Reason string `json:"reason"`
+}
+
+func apiBanUser(c *fiber.Ctx) error {
+	var req apiBanUserRequest
+	err := c.BodyParser(&req)
+	if err != nil {
+		cfg.Logger.Error("Can't parse the ban user request", map[string]interface{}{"error": err.Error()})
+		return err
+	}
+	bannedUsersIDs[req.UserID] = req.Reason
+	cfg.Logger.Info("Banned user", map[string]interface{}{"user_id": req.UserID, "reason": req.Reason})
+	storeBannedUsers()
+	c.Status(200).SendString("OK: user banned")
+	return nil
+}
+
+func apiUnbanUser(c *fiber.Ctx) error {
+	var req apiBanUserRequest
+	err := c.BodyParser(&req)
+	if err != nil {
+		cfg.Logger.Error("Can't parse the unban user request", map[string]interface{}{"error": err.Error()})
+		return err
+	}
+	delete(bannedUsersIDs, req.UserID)
+	cfg.Logger.Info("Unbanned user", map[string]interface{}{"user_id": req.UserID})
+	storeBannedUsers()
+	c.Status(200).SendString("OK: user unbanned")
+	return nil
+}
+
+func storeBannedUsers() {
+	fileLock := flock.New(fmt.Sprintf("%s.lock", cfg.Api.BannedUsersFile))
+	err := fileLock.Lock()
+	if err != nil {
+		cfg.Logger.Error("Can't lock the file", map[string]interface{}{"error": err.Error()})
+		return
+	}
+	defer fileLock.Unlock()
+	data, err := json.Marshal(bannedUsersIDs)
+	if err != nil {
+		cfg.Logger.Error("Can't marshal banned users", map[string]interface{}{"error": err.Error()})
+		return
+	}
+	err = os.WriteFile(cfg.Api.BannedUsersFile, data, 0644)
+	if err != nil {
+		cfg.Logger.Error("Can't write banned users to file", map[string]interface{}{"error": err.Error()})
+		return
+	}
+}
+
+func loadBannedUsers() {
+	if _, err := os.Stat(cfg.Api.BannedUsersFile); os.IsNotExist(err) {
+		cfg.Logger.Info("Banned users file doesn't exist - creating it", map[string]interface{}{"file": cfg.Api.BannedUsersFile})
+		_, err := os.Create(cfg.Api.BannedUsersFile)
+		if err != nil {
+			cfg.Logger.Error("Can't create the file", map[string]interface{}{"error": err.Error()})
+			return
+		}
+	}
+
+	fileLock := flock.New(fmt.Sprintf("%s.lock", cfg.Api.BannedUsersFile))
+	err := fileLock.RLock() // Use RLock for read lock
+	if err != nil {
+		cfg.Logger.Error("Can't lock the file [load]", map[string]interface{}{"error": err.Error()})
+		return
+	}
+	defer fileLock.Unlock()
+
+	data, err := os.ReadFile(cfg.Api.BannedUsersFile)
+	if err != nil {
+		cfg.Logger.Error("Can't read banned users from file", map[string]interface{}{"error": err.Error()})
+		return
+	}
+	err = json.Unmarshal(data, &bannedUsersIDs)
+	if err != nil {
+		cfg.Logger.Error("Can't unmarshal banned users", map[string]interface{}{"error": err.Error()})
+		return
+	}
+}