Add initial code (#1)

go.mod

@@ -0,0 +1,5 @@
+module github.com/invliD/palworld-rcon
+
+go 1.21.3
+
+require github.com/gorcon/rcon v1.3.5

go.sum

@@ -0,0 +1,2 @@
+github.com/gorcon/rcon v1.3.5 h1:YE/Vrw6R99uEP08wp0EjdPAP3Jwz/ys3J8qxI1nYoeU=
+github.com/gorcon/rcon v1.3.5/go.mod h1:zR1qfKZttF8vAgH1NsP6CdpachOvLDq8jE64NboTpIM=

rcon.go

@@ -0,0 +1,187 @@
+package palworldrcon
+
+import (
+	"encoding/csv"
+	"errors"
+	"fmt"
+	"io"
+	"regexp"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/gorcon/rcon"
+)
+
+type Client struct {
+	address  string
+	password string
+	conn     *rcon.Conn
+}
+
+func NewClient(address string, password string) *Client {
+	client := &Client{
+		address:  address,
+		password: password,
+	}
+	return client
+}
+
+func (r *Client) connect() error {
+	if r.conn != nil {
+		r.conn.Close()
+		r.conn = nil
+	}
+	conn, err := rcon.Dial(r.address, r.password)
+	if err != nil {
+		return err
+	}
+	r.conn = conn
+	return nil
+}
+
+func (r *Client) executeWithRetry(command string, retry bool) (string, error) {
+	if r.conn == nil {
+		err := r.connect()
+		if err != nil {
+			return "", err
+		}
+	}
+	response, err := r.conn.Execute(command)
+	if (errors.Is(err, io.EOF) || errors.Is(err, syscall.EPIPE)) && retry {
+		err := r.connect()
+		if err != nil {
+			return "", err
+		}
+		return r.executeWithRetry(command, false)
+	}
+	return strings.TrimSpace(response), err
+}
+
+func (r *Client) BanPlayer(steamID uint64) error {
+	response, err := r.executeWithRetry(fmt.Sprintf("BanPlayer %d", steamID), true)
+	if err != nil {
+		return err
+	} else if !strings.HasPrefix(response, "Baned: ") { // sic!
+		return fmt.Errorf("failed to ban player: %s", response)
+	}
+	return nil
+}
+
+func (r *Client) Broadcast(message string) error {
+	response, err := r.executeWithRetry(fmt.Sprintf("Broadcast %s", message), true)
+	if err != nil {
+		return err
+	} else if !strings.HasPrefix(response, "Broadcasted: ") {
+		return fmt.Errorf("failed to broadcast: %s", response)
+	}
+	return nil
+}
+
+func (r *Client) DoExit() error {
+	response, err := r.executeWithRetry("DoExit", true)
+	if err != nil {
+		return err
+	} else if response != "Shutdown..." {
+		return fmt.Errorf("failed to shut down: %s", response)
+	}
+	return nil
+}
+
+type ServerInfo struct {
+	ServerName string
+	Version    string
+}
+
+var infoRegex = regexp.MustCompile(`^Welcome to Pal Server\[v([\d\.]+)\]\s*(.*?)$`)
+
+func (r *Client) Info() (*ServerInfo, error) {
+	response, err := r.executeWithRetry("Info", true)
+	if err != nil {
+		return nil, err
+	}
+	infoMatches := infoRegex.FindStringSubmatch(response)
+	if infoMatches == nil {
+		return nil, fmt.Errorf("failed to parse Info output: %s", response)
+	}
+	return &ServerInfo{
+		ServerName: infoMatches[2],
+		Version:    infoMatches[1],
+	}, nil
+}
+
+func (r *Client) KickPlayer(steamID uint64) error {
+	response, err := r.executeWithRetry(fmt.Sprintf("KickPlayer %d", steamID), true)
+	if err != nil {
+		return err
+	} else if !strings.HasPrefix(response, "Kicked: ") {
+		return fmt.Errorf("failed to kick player: %s", response)
+	}
+	return nil
+}
+
+func (r *Client) Save() error {
+	response, err := r.executeWithRetry("Save", true)
+	if err != nil {
+		return err
+	} else if response != "Complete Save" {
+		return fmt.Errorf("failed to save: %s", response)
+	}
+	return nil
+}
+
+type Player struct {
+	Name      string
+	PlayerUID uint64
+	SteamID   uint64
+}
+
+func (r *Client) ShowPlayers() ([]Player, error) {
+	players := []Player{}
+	response, err := r.executeWithRetry("ShowPlayers", true)
+	if err != nil {
+		return players, err
+	}
+	c := csv.NewReader(strings.NewReader(strings.TrimSpace(response)))
+	records, err := c.ReadAll()
+	if err != nil {
+		return players, fmt.Errorf("failed to parse ShowPlayers response as CSV: %w", err)
+	}
+	for _, record := range records[1:] {
+		if len(record) != 3 {
+			return players, fmt.Errorf("failed to parse player output: %v", record)
+		}
+		playerUID, err := strconv.ParseUint(record[1], 10, 64)
+		if err != nil {
+			return players, fmt.Errorf("failed to parse player UID: %w", err)
+		}
+		steamID, err := strconv.ParseUint(record[2], 10, 64)
+		if err != nil {
+			return players, fmt.Errorf("failed to parse steam ID: %w", err)
+		}
+		players = append(players, Player{
+			Name:      record[0],
+			PlayerUID: playerUID,
+			SteamID:   steamID,
+		})
+	}
+	return players, nil
+}
+
+func (r *Client) Shutdown(seconds int) error {
+	return r.shutdown(fmt.Sprintf("%d", seconds))
+}
+
+func (r *Client) ShutdownWithMessage(seconds int, message string) error {
+	return r.shutdown(fmt.Sprintf("%d %s", seconds, message))
+}
+
+func (r *Client) shutdown(args string) error {
+	response, err := r.executeWithRetry(fmt.Sprintf("Shutdown %s", args), true)
+	if err != nil {
+		return nil
+	} else if !strings.HasPrefix(response, "The server will shut down") {
+		return fmt.Errorf("failed to shut down: %s", response)
+	}
+	return nil
+}