Code cleanup, only fetch stale blocked servers

.gitignore

@@ -1,3 +1,4 @@
 bin/
 config.yml
 .DS_Store
+blocked-servers.json

src/main.go

@@ -24,18 +24,20 @@ func init() {
 		log.Fatal(err)
 	}
 
+	r.SetEnabled(config.Cache.Enable)
+
+	if config.Cache.Enable {
 		if err := r.Connect(config.Redis); err != nil {
 			log.Fatal(err)
 		}
 
 		log.Println("Successfully connected to Redis")
+	}
 
 	if err := GetBlockedServerList(); err != nil {
 		log.Fatal(err)
 	}
 
-	log.Println("Successfully retrieved EULA blocked servers")
-
 	if instanceID := os.Getenv("INSTANCE_ID"); len(instanceID) > 0 {
 		value, err := strconv.ParseUint(instanceID, 10, 16)
 

src/redis.go

@@ -9,10 +9,19 @@ import (
 )
 
 type Redis struct {
+	Enabled bool
 	Client  *redis.Client
 }
 
+func (r *Redis) SetEnabled(value bool) {
+	r.Enabled = value
+}
+
 func (r *Redis) Connect(uri string) error {
+	if !r.Enabled {
+		return nil
+	}
+
 	opts, err := redis.ParseURL(uri)
 
 	if err != nil {
@@ -29,6 +38,10 @@ func (r *Redis) Connect(uri string) error {
 }
 
 func (r *Redis) Exists(key string) (bool, error) {
+	if !r.Enabled {
+		return false, nil
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 
 	defer cancel()
@@ -45,6 +58,10 @@ func (r *Redis) Exists(key string) (bool, error) {
 }
 
 func (r *Redis) GetString(key string) (string, error) {
+	if !r.Enabled {
+		return "", nil
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 
 	defer cancel()
@@ -59,6 +76,10 @@ func (r *Redis) GetString(key string) (string, error) {
 }
 
 func (r *Redis) GetBytes(key string) ([]byte, error) {
+	if !r.Enabled {
+		return nil, nil
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 
 	defer cancel()
@@ -73,6 +94,10 @@ func (r *Redis) GetBytes(key string) ([]byte, error) {
 }
 
 func (r *Redis) Set(key string, value interface{}, ttl time.Duration) error {
+	if !r.Enabled {
+		return nil
+	}
+
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
 
 	defer cancel()
@@ -81,6 +106,10 @@ func (r *Redis) Set(key string, value interface{}, ttl time.Duration) error {
 }
 
 func (r *Redis) SetJSON(key string, value interface{}, ttl time.Duration) error {
+	if !r.Enabled {
+		return nil
+	}
+
 	data, err := json.Marshal(value)
 
 	if err != nil {
@@ -91,5 +120,9 @@ func (r *Redis) SetJSON(key string, value interface{}, ttl time.Duration) error
 }
 
 func (r *Redis) Close() error {
+	if !r.Enabled {
+		return nil
+	}
+
 	return r.Client.Close()
 }

src/status.go

@@ -8,7 +8,7 @@ import (
 	"github.com/mcstatus-io/mcutil"
 )
 
-type StatusOffline struct {
+type StatusResponse struct {
 	Online      bool   `json:"online"`
 	Host        string `json:"host"`
 	Port        uint16 `json:"port"`
@@ -16,10 +16,7 @@ type StatusOffline struct {
 }
 
 type JavaStatusResponse struct {
-	Online      bool         `json:"online"`
+	StatusResponse
-	Host        string       `json:"host"`
-	Port        uint16       `json:"port"`
-	EULABlocked bool         `json:"eula_blocked"`
 	Version *JavaVersion `json:"version"`
 	Players JavaPlayers  `json:"players"`
 	MOTD    MOTD         `json:"motd"`
@@ -28,10 +25,7 @@ type JavaStatusResponse struct {
 }
 
 type BedrockStatusResponse struct {
-	Online      bool            `json:"online"`
+	StatusResponse
-	Host        string          `json:"host"`
-	Port        uint16          `json:"port"`
-	EULABlocked bool            `json:"eula_blocked"`
 	Version  *BedrockVersion `json:"version"`
 	Players  *BedrockPlayers `json:"players"`
 	MOTD     *MOTD           `json:"motd"`
@@ -84,25 +78,21 @@ type Mod struct {
 func GetJavaStatus(host string, port uint16) (interface{}, error) {
 	cacheKey := fmt.Sprintf("java:%s-%d", host, port)
 
-	if config.Cache.Enable {
+	cacheExists, err := r.Exists(cacheKey)
-		exists, err := r.Exists(cacheKey)
 
 	if err != nil {
 		return nil, err
 	}
 
-		if exists {
+	if cacheExists {
 		return r.GetString(cacheKey)
 	}
-	}
 
 	response := FetchJavaStatus(host, port)
 
-	if config.Cache.Enable {
 	if err := r.SetJSON(cacheKey, response, config.Cache.JavaCacheDuration); err != nil {
 		return nil, err
 	}
-	}
 
 	return response, nil
 }
@@ -110,25 +100,21 @@ func GetJavaStatus(host string, port uint16) (interface{}, error) {
 func GetBedrockStatus(host string, port uint16) (interface{}, error) {
 	cacheKey := fmt.Sprintf("bedrock:%s-%d", host, port)
 
-	if config.Cache.Enable {
+	cacheExists, err := r.Exists(cacheKey)
-		exists, err := r.Exists(cacheKey)
 
 	if err != nil {
 		return nil, err
 	}
 
-		if exists {
+	if cacheExists {
 		return r.GetString(cacheKey)
 	}
-	}
 
 	response := FetchBedrockStatus(host, port)
 
-	if config.Cache.Enable {
 	if err := r.SetJSON(cacheKey, response, config.Cache.BedrockCacheDuration); err != nil {
 		return nil, err
 	}
-	}
 
 	return response, nil
 }
@@ -136,17 +122,15 @@ func GetBedrockStatus(host string, port uint16) (interface{}, error) {
 func GetServerIcon(host string, port uint16) ([]byte, error) {
 	cacheKey := fmt.Sprintf("icon:%s-%d", host, port)
 
-	if config.Cache.Enable {
+	cacheExists, err := r.Exists(cacheKey)
-		exists, err := r.Exists(cacheKey)
 
 	if err != nil {
 		return nil, err
 	}
 
-		if exists {
+	if cacheExists {
 		return r.GetBytes(cacheKey)
 	}
-	}
 
 	icon := defaultIconBytes
 
@@ -162,11 +146,9 @@ func GetServerIcon(host string, port uint16) ([]byte, error) {
 		icon = data
 	}
 
-	if config.Cache.Enable {
 	if err := r.Set(cacheKey, icon, config.Cache.IconCacheDuration); err != nil {
 		return nil, err
 	}
-	}
 
 	return icon, nil
 }
@@ -178,7 +160,7 @@ func FetchJavaStatus(host string, port uint16) interface{} {
 		statusLegacy, err := mcutil.StatusLegacy(host, port)
 
 		if err != nil {
-			return StatusOffline{
+			return StatusResponse{
 				Online:      false,
 				Host:        host,
 				Port:        port,
@@ -187,10 +169,12 @@ func FetchJavaStatus(host string, port uint16) interface{} {
 		}
 
 		response := JavaStatusResponse{
+			StatusResponse: StatusResponse{
 				Online:      true,
 				Host:        host,
 				Port:        port,
 				EULABlocked: IsBlockedAddress(host),
+			},
 			Version: nil,
 			Players: JavaPlayers{
 				Online: statusLegacy.Players.Online,
@@ -243,10 +227,12 @@ func FetchJavaStatus(host string, port uint16) interface{} {
 	}
 
 	return JavaStatusResponse{
+		StatusResponse: StatusResponse{
 			Online:      true,
 			Host:        host,
 			Port:        port,
 			EULABlocked: IsBlockedAddress(host),
+		},
 		Version: &JavaVersion{
 			NameRaw:   status.Version.NameRaw,
 			NameClean: status.Version.NameClean,
@@ -272,7 +258,7 @@ func FetchBedrockStatus(host string, port uint16) interface{} {
 	status, err := mcutil.StatusBedrock(host, port)
 
 	if err != nil {
-		return StatusOffline{
+		return StatusResponse{
 			Online:      false,
 			Host:        host,
 			Port:        port,
@@ -281,10 +267,12 @@ func FetchBedrockStatus(host string, port uint16) interface{} {
 	}
 
 	response := BedrockStatusResponse{
+		StatusResponse: StatusResponse{
 			Online:      true,
 			Host:        host,
 			Port:        port,
 			EULABlocked: IsBlockedAddress(host),
+		},
 		Version:  nil,
 		Players:  nil,
 		MOTD:     nil,

src/util.go

@@ -4,20 +4,29 @@ import (
 	"crypto/sha1"
 	_ "embed"
 	"encoding/hex"
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"net/http"
+	"os"
 	"regexp"
 	"strconv"
 	"strings"
+	"time"
 )
 
 var (
 	//go:embed icon.png
 	defaultIconBytes []byte
-	ipAddressRegExp  = regexp.MustCompile("^\\d{1,3}(\\.\\d{1,3}){3}$")
+	ipAddressRegExp  = regexp.MustCompile(`^\d{1,3}(\.\d{1,3}){3}$`)
 )
 
+type BlockedServersFile struct {
+	LastUpdated time.Time `json:"last_updated"`
+	Servers     []string  `json:"servers"`
+}
+
 func Contains[T comparable](arr []T, v T) bool {
 	for _, value := range arr {
 		if v == value {
@@ -29,6 +38,36 @@ func Contains[T comparable](arr []T, v T) bool {
 }
 
 func GetBlockedServerList() error {
+	f, err := os.OpenFile("blocked-servers.json", os.O_CREATE|os.O_RDWR, 0777)
+
+	if err != nil {
+		return err
+	}
+
+	defer f.Close()
+
+	data, err := ioutil.ReadAll(f)
+
+	if err != nil {
+		return err
+	}
+
+	if len(data) > 0 {
+		var blockedServersFile BlockedServersFile
+
+		if err = json.Unmarshal(data, &blockedServersFile); err != nil {
+			return err
+		}
+
+		if time.Since(blockedServersFile.LastUpdated).Hours() < 24 {
+			blockedServersMutex.Lock()
+			blockedServers = blockedServersFile.Servers
+			blockedServersMutex.Unlock()
+
+			return nil
+		}
+	}
+
 	resp, err := http.Get("https://sessionserver.mojang.com/blockedservers")
 
 	if err != nil {
@@ -39,6 +78,8 @@ func GetBlockedServerList() error {
 		return fmt.Errorf("unexpected status code: %d", resp.StatusCode)
 	}
 
+	log.Println("Successfully retrieved EULA blocked servers")
+
 	defer resp.Body.Close()
 
 	body, err := ioutil.ReadAll(resp.Body)
@@ -49,9 +90,27 @@ func GetBlockedServerList() error {
 
 	blockedServersMutex.Lock()
 	blockedServers = strings.Split(string(body), "\n")
-	blockedServersMutex.Unlock()
 
-	return nil
+	defer blockedServersMutex.Unlock()
+
+	if data, err = json.Marshal(BlockedServersFile{
+		LastUpdated: time.Now(),
+		Servers:     blockedServers,
+	}); err != nil {
+		return err
+	}
+
+	if err = f.Truncate(0); err != nil {
+		return err
+	}
+
+	if _, err = f.Seek(0, 0); err != nil {
+		return err
+	}
+
+	_, err = f.Write(data)
+
+	return err
 }
 
 func IsBlockedAddress(address string) bool {