Merge pull request #197 from robinje/bloomfilter

New Character Name Checking

README.md

@@ -1,3 +1,16 @@
+[![License](https://img.shields.io/badge/License-Apache_2.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
+![GitHub](https://img.shields.io/badge/github-%23121011.svg?style=for-the-badge&logo=github&logoColor=white)
+![Dependabot](https://img.shields.io/badge/dependabot-025E8C?style=for-the-badge&logo=dependabot&logoColor=white)
+![GitHub Actions](https://img.shields.io/badge/github%20actions-%232671E5.svg?style=for-the-badge&logo=githubactions&logoColor=white)
+![AWS](https://img.shields.io/badge/AWS-%23FF9900.svg?style=for-the-badge&logo=amazon-aws&logoColor=white)
+![AmazonDynamoDB](https://img.shields.io/badge/Amazon%20DynamoDB-4053D6?style=for-the-badge&logo=Amazon%20DynamoDB&logoColor=white)
+![Webpack](https://img.shields.io/badge/webpack-%238DD6F9.svg?style=for-the-badge&logo=webpack&logoColor=black)
+![Go](https://img.shields.io/badge/go-%2300ADD8.svg?style=for-the-badge&logo=go&logoColor=white)
+![Python](https://img.shields.io/badge/python-3670A0?style=for-the-badge&logo=python&logoColor=ffdd54)
+![JavaScript](https://img.shields.io/badge/javascript-%23323330.svg?style=for-the-badge&logo=javascript&logoColor=%23F7DF1E)
+![Linux](https://img.shields.io/badge/Linux-FCC624?style=for-the-badge&logo=linux&logoColor=black)
+![Windows](https://img.shields.io/badge/Windows-0078D6?style=for-the-badge&logo=windows&logoColor=white)
+
 # Multi-User Dungeon Engine
 
 The goal of this project is to create a commercial-quality multi-user dungeon (MUD) engine that is flexible enough to be used as either a conventional MUD or an interactive fiction game.
@@ -16,7 +29,7 @@ The current implementation includes an SSH server for secure authentication and
 - [x] Build an interactive password change system.
 - [ ] Construct the item system.
 - [ ] Develop game mechanics.
-- [ ] Design an ecenomic framework.
+- [ ] Design an economic framework
 - [ ] Implement a world creation system.
 - [ ] Develop simple Non-Player Characters (NPCs).
 - [ ] Design and implement a quest system.
@@ -47,8 +60,9 @@ The current implementation includes an SSH server for secure authentication and
 - [x] Implement Persistent Logging.
 - [x] Load item prototypes at start.
 - [x] Create function for creating items from prototypes.
-- [x] Ensure that a message is passed when a characters is added to the game.
+- [x] Ensure that a message is passed when a character is added to the game.
 - [x] Add a Message of the Day (MOTD) command.
+- [x] Add Bloom Filter to check for existing characters names being used.
 - [ ] Add the ability to delete characters.
 - [ ] Add the ability to delete accounts.
 - [ ] Implement an obscenity filter.

core/character.go

@@ -7,9 +7,12 @@ import (
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/service/dynamodb"
 	"github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute"
+	"github.com/bits-and-blooms/bloom/v3"
 	"github.com/google/uuid"
 )
 
+const FalsePositiveRate = 0.01 // 1% false positive rate
+
 // WearLocations defines all possible locations where an item can be worn
 var WearLocations = map[string]bool{
 	"head":         true,
@@ -94,6 +97,8 @@ func (s *Server) NewCharacter(name string, player *Player, room *Room, archetype
 		Server:     s,
 	}
 
+	s.AddCharacterName(name)
+
 	if archetypeName != "" {
 		if archetype, ok := s.Archetypes.Archetypes[archetypeName]; ok {
 			character.Attributes = make(map[string]float64)
@@ -192,6 +197,36 @@ func (kp *KeyPair) LoadCharacterNames() (map[string]bool, error) {
 	return names, nil
 }
 
+func (server *Server) InitializeBloomFilter() error {
+	characterNames, err := server.Database.LoadCharacterNames()
+	if err != nil {
+		return fmt.Errorf("failed to load character names: %w", err)
+	}
+
+	n := uint(len(characterNames))
+	fpRate := FalsePositiveRate
+
+	server.CharacterBloomFilter = bloom.NewWithEstimates(n, fpRate)
+
+	for name := range characterNames {
+		server.CharacterBloomFilter.Add([]byte(strings.ToLower(name)))
+	}
+
+	return nil
+}
+
+func (server *Server) AddCharacterName(name string) {
+	server.Mutex.Lock()
+	defer server.Mutex.Unlock()
+
+	server.CharacterBloomFilter.AddString(strings.ToLower(name))
+}
+
+func (server *Server) CharacterNameExists(name string) bool {
+
+	return server.CharacterBloomFilter.TestString(strings.ToLower(name))
+}
+
 func SaveActiveCharacters(s *Server) error {
 	s.Mutex.Lock()
 	defer s.Mutex.Unlock()

core/go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/cloudwatch v1.40.5
 	github.com/aws/aws-sdk-go-v2/service/cloudwatchlogs v1.37.5
 	github.com/aws/aws-xray-sdk-go v1.8.4
+	github.com/bits-and-blooms/bloom/v3 v3.7.0
 	github.com/google/uuid v1.6.0
 	golang.org/x/crypto v0.24.0
 )
@@ -27,6 +28,7 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.26.5 // indirect
 	github.com/aws/aws-sdk-go-v2/service/sts v1.30.5 // indirect
 	github.com/aws/smithy-go v1.20.4 // indirect
+	github.com/bits-and-blooms/bitset v1.14.3 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/klauspost/compress v1.17.2 // indirect

core/player.go

@@ -306,8 +306,8 @@ func CreateCharacter(player *Player, server *Server) (*Character, error) {
 		return nil, fmt.Errorf("character name must be 15 characters or fewer")
 	}
 
-	if server.CharacterExists[strings.ToLower(charName)] {
-		return nil, fmt.Errorf("character already exists")
+	if server.CharacterNameExists(charName) {
+		return nil, fmt.Errorf("character name already exists")
 	}
 
 	var selectedArchetype string

core/types.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/aws/aws-sdk-go-v2/service/cloudwatchlogs"
 	"github.com/aws/aws-sdk-go/service/dynamodb"
+	"github.com/bits-and-blooms/bloom/v3"
 	"github.com/google/uuid"
 	"golang.org/x/crypto/ssh"
 )
@@ -54,27 +55,27 @@ type KeyPair struct {
 }
 
 type Server struct {
-	Port            uint16
-	Listener        net.Listener
-	SSHConfig       *ssh.ServerConfig
-	PlayerCount     uint64
-	Config          Configuration
-	StartTime       time.Time
-	Rooms           map[int64]*Room
-	Database        *KeyPair
-	PlayerIndex     *Index
-	CharacterExists map[string]bool
-	Characters      map[uuid.UUID]*Character
-	Balance         float64
-	AutoSave        uint16
-	Archetypes      *ArchetypesData
-	Health          uint16
-	Essence         uint16
-	Items           map[uint64]*Item
-	ItemPrototypes  map[uint64]*Item
-	Context         context.Context
-	Mutex           sync.Mutex
-	ActiveMotDs     []*MOTD
+	Port                 uint16
+	Listener             net.Listener
+	SSHConfig            *ssh.ServerConfig
+	PlayerCount          uint64
+	Config               Configuration
+	StartTime            time.Time
+	Rooms                map[int64]*Room
+	Database             *KeyPair
+	PlayerIndex          *Index
+	CharacterBloomFilter *bloom.BloomFilter
+	Characters           map[uuid.UUID]*Character
+	Balance              float64
+	AutoSave             uint16
+	Archetypes           *ArchetypesData
+	Health               uint16
+	Essence              uint16
+	Items                map[uint64]*Item
+	ItemPrototypes       map[uint64]*Item
+	Context              context.Context
+	Mutex                sync.Mutex
+	ActiveMotDs          []*MOTD
 }
 
 type Player struct {

ssh_server/go.mod

@@ -31,6 +31,8 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/sts v1.30.5 // indirect
 	github.com/aws/aws-xray-sdk-go v1.8.4 // indirect
 	github.com/aws/smithy-go v1.20.4 // indirect
+	github.com/bits-and-blooms/bitset v1.14.3 // indirect
+	github.com/bits-and-blooms/bloom/v3 v3.7.0 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/klauspost/compress v1.17.2 // indirect

ssh_server/server.go

@@ -49,9 +49,10 @@ func NewServer(config core.Configuration) (*core.Server, error) {
 
 	core.Logger.Info("Loading character names from database...")
 
-	server.CharacterExists, err = server.Database.LoadCharacterNames()
+	// Load the bloom filter from the database
+	err = server.InitializeBloomFilter()
 	if err != nil {
-		core.Logger.Error("Error loading character names from database", "error", err)
+		core.Logger.Error("Error initializing bloom filter", "error", err)
 	}
 
 	server.Archetypes, err = server.Database.LoadArchetypes()