unexport request, response methods

{request}.buf initialised with 0 length.

encoder, decoder interfaces added.

.gitignore

@@ -24,6 +24,7 @@ go.work.sum
 
 # env file
 .env
+.envrc
 
 # Added by goreleaser init:
 dist/

CHANGELOG.md

@@ -11,7 +11,20 @@ Before any major/minor/patch bump all unit tests will be run to verify they pass
 
 -   [x]
 
-# [0.4.0] - 2026-02-15
+# [0.5.1] - 2026-02-18
+
+### Added
+
+- CLI configuration can be managed through env vars, see [Environment Variables](https://github.com/onyx-and-iris/q3rcon?tab=readme-ov-file#environment-variables) under Configuration in README.
+
+### Changed
+
+- The CLI now supports `--long` and `-short` style flags. Several examples in README.
+- `--help` output has been improved.
+- Colour codes have been removed from CLI output. This makes the responses easier to read.
+
+
+# [0.4.1] - 2026-02-15
 
 ### Added
 

README.md

@@ -17,9 +17,15 @@ Quake3 Rcon works by firing UDP packets to the game server port, responses may b
 
 Rcon itself is insecure and each packet includes the password so I don't suggest using it remotely. If you have direct access to the server then SSH in first, then use this tool locally.
 
-## Use
+---
 
-`go get github.com/onyx-and-iris/q3rcon`
+## Package
+
+#### Use
+
+```console
+go get github.com/onyx-and-iris/q3rcon
+```
 
 ```go
 package main
@@ -91,12 +97,24 @@ rcon, err := q3rcon.New(
 	q3rcon.WithTimeouts(timeouts))
 ```
 
+---
+
 ## Command line
 
-Pass `host`, `port` and `rconpass` as flags, for example:
+### Install
 
+```console
+go install github.com/onyx-and-iris/q3rcon/cmd/q3rcon@latest
 ```
-q3rcon -H=localhost -p=30000 -r="rconpassword" "mapname"
+
+### Configuration
+
+#### Flags
+
+Pass `--host`, `--port` and `--rconpass` as flags, for example:
+
+```console
+q3rcon --host=localhost --port=30000 --rconpass="rconpassword" "mapname"
 ```
 
 -   `host` defaults to "localhost"
@@ -105,25 +123,41 @@ q3rcon -H=localhost -p=30000 -r="rconpassword" "mapname"
 
 Arguments following the flags will be sent as rcon commands. You may send multiple arguments.
 
-#### Interactive mode
+#### Environment Variables
+
+example .envrc:
+
+```bash
+#!/usr/bin/env bash
+
+export Q3RCON_HOST="localhost"
+export Q3RCON_PORT=28960
+export Q3RCON_RCONPASS="rconpassword"
+```
+
+### Interactive mode
 
 Pass `interactive (-i shorthand)` flag to enable interactive mode, for example:
 
-```bash
-q3rcon -h=localhost -p=30000 -r="rconpassword" -i
+```console
+q3rcon -H=localhost -p=30000 -r="rconpassword" -i
 ```
 
 If interactive mode is enabled, any arguments sent on the command line will be ignored.
 
+---
+
 ## Your own implementation
 
-The included CLI is a generic implementation, while it can be used out of the box you may find that some requests result in fragmented responses. The solution is to implement your own version, adjusting the timings with the functional options as detailed above. I could have increased the default timeouts but that would add unnecessary delay for most requests, so I decided to leave those details to the users of the package.
+The included CLI is a generic implementation, while it can be used out of the box you may find that some requests result in fragmented responses. The solution is to implement your own version, adjusting the timings with the functional options as detailed above.
 
-Since you can include the q3rcon package into your own package you can easily make your own modifications, for example, I added [colour to the terminal][status] and [reformatted some of the responses][mapname].
+Since you can include the q3rcon package into your own CLI/package you can easily make your own modifications, for example, I added [colour to the terminal][status] and [tabulated some of the responses][mapname].
+
+---
 
 ## Logging
 
-The `-loglevel` flag allows you to control the verbosity of the application's logging output. 
+The `--loglevel` flag allows you to control the verbosity of the application's logging output. 
 
 Acceptable values for this flag are:
 
@@ -137,8 +171,8 @@ Acceptable values for this flag are:
 
 For example, to set the log level to `debug`, you can use:
 
-```bash
-q3rcon -p=28960 -r="rconpassword" -loglevel=debug -i
+```console
+q3rcon -H=localhost -p=28960 -r="rconpassword" -l=debug -i
 ```
 
 The default log level is `warn` if the flag is not specified.

cmd/q3rcon/main.go

@@ -2,21 +2,51 @@ package main
 
 import (
 	"bufio"
-	"flag"
+	"errors"
 	"fmt"
 	"io"
 	"os"
+	"regexp"
 	"runtime/debug"
 	"strings"
 	"time"
 
 	"github.com/charmbracelet/log"
+	"github.com/peterbourgon/ff/v4"
+	"github.com/peterbourgon/ff/v4/ffhelp"
 
 	"github.com/onyx-and-iris/q3rcon"
 )
 
 var version string // Version will be set at build time
 
+type Flags struct {
+	Host        string
+	Port        int
+	Rconpass    string
+	Interactive bool
+	LogLevel    string
+	Version     bool
+}
+
+func (f Flags) Validate() error {
+	if f.Port < 1024 || f.Port > 65535 {
+		return fmt.Errorf(
+			"invalid port value, got: (%d) expected: in range 1024-65535",
+			f.Port,
+		)
+	}
+
+	if len(f.Rconpass) < 8 {
+		return fmt.Errorf(
+			"invalid rcon password, got: (%s) expected: at least 8 characters",
+			f.Rconpass,
+		)
+	}
+
+	return nil
+}
+
 func main() {
 	var exitCode int
 
@@ -39,71 +69,67 @@ func main() {
 
 // run executes the main logic of the application and returns a cleanup function and an error if any.
 func run() (func(), error) {
-	var (
-		host        string
-		port        int
-		rconpass    string
-		interactive bool
-		loglevel    string
-		versionFlag bool
-	)
+	var flags Flags
 
-	flag.StringVar(&host, "host", "localhost", "hostname of the gameserver")
-	flag.StringVar(&host, "H", "localhost", "hostname of the gameserver (shorthand)")
-	flag.IntVar(&port, "port", 28960, "port on which the gameserver resides, default is 28960")
-	flag.IntVar(
-		&port,
-		"p",
+	fs := ff.NewFlagSet("q3rcon - A command-line RCON client for Q3 Rcon compatible game servers")
+	fs.StringVar(&flags.Host, 'H', "host", "localhost", "hostname of the gameserver")
+	fs.IntVar(
+		&flags.Port,
+		'p',
+		"port",
 		28960,
-		"port on which the gameserver resides, default is 28960 (shorthand)",
+		"port on which the gameserver resides, default is 28960",
 	)
-	flag.StringVar(&rconpass, "rconpass", os.Getenv("RCON_PASS"), "rcon password of the gameserver")
-	flag.StringVar(
-		&rconpass,
-		"r",
-		os.Getenv("RCON_PASS"),
-		"rcon password of the gameserver (shorthand)",
+	fs.StringVar(
+		&flags.Rconpass,
+		'r',
+		"rconpass",
+		"",
+		"rcon password of the gameserver",
 	)
 
-	flag.BoolVar(&interactive, "interactive", false, "run in interactive mode")
-	flag.BoolVar(&interactive, "i", false, "run in interactive mode (shorthand)")
+	fs.BoolVar(&flags.Interactive, 'i', "interactive", "run in interactive mode")
+	fs.StringVar(
+		&flags.LogLevel,
+		'l',
+		"loglevel",
+		"info",
+		"Log level (debug, info, warn, error, fatal, panic)",
+	)
+	fs.BoolVar(&flags.Version, 'v', "version", "print version information and exit")
 
-	flag.StringVar(&loglevel, "loglevel", "warn", "log level")
-	flag.StringVar(&loglevel, "l", "warn", "log level (shorthand)")
+	err := ff.Parse(fs, os.Args[1:],
+		ff.WithEnvVarPrefix("Q3RCON"),
+	)
+	switch {
+	case errors.Is(err, ff.ErrHelp):
+		fmt.Fprintf(os.Stderr, "%s\n", ffhelp.Flags(fs, "q3rcon [flags] <rcon commands>"))
+		return nil, nil
+	case err != nil:
+		return nil, fmt.Errorf("failed to parse flags: %w", err)
+	}
 
-	flag.BoolVar(&versionFlag, "version", false, "print version information and exit")
-	flag.BoolVar(&versionFlag, "v", false, "print version information and exit (shorthand)")
-
-	flag.Parse()
-
-	if versionFlag {
+	if flags.Version {
 		fmt.Printf("q3rcon version: %s\n", versionFromBuild())
 		return nil, nil
 	}
 
-	level, err := log.ParseLevel(loglevel)
+	if err := flags.Validate(); err != nil {
+		return nil, err
+	}
+
+	level, err := log.ParseLevel(flags.LogLevel)
 	if err != nil {
-		return nil, fmt.Errorf("invalid log level: %s", loglevel)
+		return nil, fmt.Errorf("invalid log level: %s", flags.LogLevel)
 	}
 	log.SetLevel(level)
 
-	if port < 1024 || port > 65535 {
-		return nil, fmt.Errorf("invalid port value, got: (%d) expected: in range 1024-65535", port)
-	}
-
-	if len(rconpass) < 8 {
-		return nil, fmt.Errorf(
-			"invalid rcon password, got: (%s) expected: at least 8 characters",
-			rconpass,
-		)
-	}
-
-	client, closer, err := connectRcon(host, port, rconpass)
+	client, closer, err := connectRcon(flags.Host, flags.Port, flags.Rconpass)
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to rcon: %w", err)
 	}
 
-	if interactive {
+	if flags.Interactive {
 		fmt.Printf("Enter 'Q' to exit.\n>> ")
 		err := interactiveMode(client, os.Stdin)
 		if err != nil {
@@ -112,7 +138,7 @@ func run() (func(), error) {
 		return closer, nil
 	}
 
-	commands := flag.Args()
+	commands := fs.GetArgs()
 	if len(commands) == 0 {
 		log.Debug("no commands provided, defaulting to 'status'")
 		commands = append(commands, "status")
@@ -163,7 +189,7 @@ func runCommands(client *q3rcon.Rcon, commands []string) {
 			log.Error(err)
 			continue
 		}
-		fmt.Print(resp)
+		fmt.Print(removeColourCodes(resp))
 	}
 }
 
@@ -179,9 +205,10 @@ func interactiveMode(client *q3rcon.Rcon, input io.Reader) error {
 		resp, err := client.Send(cmd)
 		if err != nil {
 			log.Error(err)
+			fmt.Print(">> ")
 			continue
 		}
-		fmt.Printf("%s>> ", resp)
+		fmt.Printf("%s>> ", removeColourCodes(resp))
 	}
 
 	if scanner.Err() != nil {
@@ -189,3 +216,10 @@ func interactiveMode(client *q3rcon.Rcon, input io.Reader) error {
 	}
 	return nil
 }
+
+var colourCodeRegex = regexp.MustCompile(`\^[0-9]`)
+
+// removeColourCodes removes '\^[0-9]' colour codes from the input string.
+func removeColourCodes(s string) string {
+	return colourCodeRegex.ReplaceAllString(s, "")
+}

conn.go

@@ -1,34 +1,33 @@
-package conn
+package q3rcon
 
 import (
 	"fmt"
 	"net"
-	"time"
 
-	log "github.com/sirupsen/logrus"
+	"github.com/charmbracelet/log"
 )
 
 type UDPConn struct {
 	conn *net.UDPConn
 }
 
-func New(host string, port int) (UDPConn, error) {
-	udpAddr, err := net.ResolveUDPAddr("udp4", fmt.Sprintf("%s:%d", host, port))
+func newUDPConn(host string, port int) (*UDPConn, error) {
+	udpAddr, err := net.ResolveUDPAddr("udp4", net.JoinHostPort(host, fmt.Sprintf("%d", port)))
 	if err != nil {
-		return UDPConn{}, err
+		return nil, err
 	}
 	conn, err := net.DialUDP("udp4", nil, udpAddr)
 	if err != nil {
-		return UDPConn{}, err
+		return nil, err
 	}
 	log.Infof("Outgoing address %s", conn.RemoteAddr())
 
-	return UDPConn{
+	return &UDPConn{
 		conn: conn,
 	}, nil
 }
 
-func (c UDPConn) Write(buf []byte) (int, error) {
+func (c *UDPConn) Write(buf []byte) (int, error) {
 	n, err := c.conn.Write(buf)
 	if err != nil {
 		return 0, err
@@ -37,8 +36,7 @@ func (c UDPConn) Write(buf []byte) (int, error) {
 	return n, nil
 }
 
-func (c UDPConn) ReadUntil(timeout time.Time, buf []byte) (int, error) {
-	c.conn.SetReadDeadline(timeout)
+func (c *UDPConn) Read(buf []byte) (int, error) {
 	rlen, _, err := c.conn.ReadFromUDP(buf)
 	if err != nil {
 		return 0, err
@@ -46,7 +44,7 @@ func (c UDPConn) ReadUntil(timeout time.Time, buf []byte) (int, error) {
 	return rlen, nil
 }
 
-func (c UDPConn) Close() error {
+func (c *UDPConn) Close() error {
 	err := c.conn.Close()
 	if err != nil {
 		return err

go.mod

@@ -4,7 +4,7 @@ go 1.25.0
 
 require (
 	github.com/charmbracelet/log v0.4.2
-	github.com/sirupsen/logrus v1.9.3
+	github.com/peterbourgon/ff/v4 v4.0.0-beta.1
 )
 
 require (

go.sum

@@ -12,7 +12,6 @@ github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd h1:vy0G
 github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd/go.mod h1:xe0nKWGd3eJgtqZRaN9RjMtK7xUYchjzPr7q6kcvCCs=
 github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
 github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-logfmt/logfmt v0.6.0 h1:wGYYu3uicYdqXVgoYbvnkrPVXkuLM1p1ifugDMEdRi4=
@@ -25,26 +24,25 @@ github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6T
 github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/muesli/termenv v0.16.0 h1:S5AlUN9dENB57rsbnkPyfdGuWIlkmzJjbFf0Tf5FWUc=
 github.com/muesli/termenv v0.16.0/go.mod h1:ZRfOIKPFDYQoDFF4Olj7/QJbW60Ol/kL1pU3VfY/Cnk=
+github.com/pelletier/go-toml/v2 v2.0.9 h1:uH2qQXheeefCCkuBBSLi7jCiSmj3VRh2+Goq2N7Xxu0=
+github.com/pelletier/go-toml/v2 v2.0.9/go.mod h1:tJU2Z3ZkXwnxa4DPO899bsyIoywizdUvyaeZurnPPDc=
+github.com/peterbourgon/ff/v4 v4.0.0-beta.1 h1:hV8qRu3V7YfiSMsBSfPfdcznAvPQd3jI5zDddSrDoUc=
+github.com/peterbourgon/ff/v4 v4.0.0-beta.1/go.mod h1:onQJUKipvCyFmZ1rIYwFAh1BhPOvftb1uhvSI7krNLc=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
-github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
-github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
 golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
 golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
-golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.34.0 h1:H5Y5sJ2L2JRdyv7ROF1he/lPdvFsd0mJHFw2ThKHxLA=
 golang.org/x/sys v0.34.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/packet/request.go

@@ -1,36 +0,0 @@
-package packet
-
-import (
-	"bytes"
-	"fmt"
-
-	log "github.com/sirupsen/logrus"
-)
-
-const bufSz = 512
-
-type Request struct {
-	magic    []byte
-	password string
-	buf      *bytes.Buffer
-}
-
-func NewRequest(password string) Request {
-	return Request{
-		magic:    []byte{'\xff', '\xff', '\xff', '\xff'},
-		password: password,
-		buf:      bytes.NewBuffer(make([]byte, bufSz)),
-	}
-}
-
-func (r Request) Header() []byte {
-	return append(r.magic, []byte("rcon")...)
-}
-
-func (r Request) Encode(cmd string) []byte {
-	r.buf.Reset()
-	r.buf.Write(r.Header())
-	r.buf.WriteString(fmt.Sprintf(" %s %s", r.password, cmd))
-	log.Tracef("Encoded request: %s", r.buf.String())
-	return r.buf.Bytes()
-}

internal/packet/response.go

@@ -1,13 +0,0 @@
-package packet
-
-type Response struct {
-	magic []byte
-}
-
-func NewResponse() Response {
-	return Response{magic: []byte{'\xff', '\xff', '\xff', '\xff'}}
-}
-
-func (r Response) Header() []byte {
-	return append(r.magic, []byte("print\n")...)
-}

q3rcon.go

@@ -1,24 +1,31 @@
 package q3rcon
 
 import (
-	"bytes"
 	"errors"
+	"fmt"
+	"io"
 	"net"
 	"strings"
 	"time"
 
-	log "github.com/sirupsen/logrus"
-
-	"github.com/onyx-and-iris/q3rcon/internal/conn"
-	"github.com/onyx-and-iris/q3rcon/internal/packet"
+	"github.com/charmbracelet/log"
 )
 
 const respBufSiz = 2048
 
+type encoder interface {
+	encode(cmd string) ([]byte, error)
+}
+
+type decoder interface {
+	isValid(buf []byte) bool
+	decode(buf []byte) string
+}
+
 type Rcon struct {
-	conn     conn.UDPConn
-	request  packet.Request
-	response packet.Response
+	conn     io.ReadWriteCloser
+	request  encoder
+	response decoder
 
 	loginTimeout   time.Duration
 	defaultTimeout time.Duration
@@ -30,15 +37,15 @@ func New(host string, port int, password string, options ...Option) (*Rcon, erro
 		return nil, errors.New("no password provided")
 	}
 
-	conn, err := conn.New(host, port)
+	conn, err := newUDPConn(host, port)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("error creating UDP connection: %w", err)
 	}
 
 	r := &Rcon{
 		conn:     conn,
-		request:  packet.NewRequest(password),
-		response: packet.NewResponse(),
+		request:  newRequest(password),
+		response: newResponse(),
 
 		loginTimeout:   5 * time.Second,
 		defaultTimeout: 20 * time.Millisecond,
@@ -50,7 +57,7 @@ func New(host string, port int, password string, options ...Option) (*Rcon, erro
 	}
 
 	if err = r.login(); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("error logging in: %w", err)
 	}
 
 	return r, nil
@@ -65,7 +72,7 @@ func (r Rcon) login() error {
 		default:
 			resp, err := r.Send("login")
 			if err != nil {
-				return err
+				return fmt.Errorf("error sending login command: %w", err)
 			}
 			if resp == "" {
 				continue
@@ -94,9 +101,14 @@ func (r Rcon) Send(cmdWithArgs string) (string, error) {
 
 	go r.listen(timeout, respChan, errChan)
 
-	_, err := r.conn.Write(r.request.Encode(cmdWithArgs))
+	encodedCmd, err := r.request.encode(cmdWithArgs)
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("error encoding command: %w", err)
+	}
+
+	_, err = r.conn.Write(encodedCmd)
+	if err != nil {
+		return "", fmt.Errorf("error writing command to connection: %w", err)
 	}
 
 	select {
@@ -118,7 +130,17 @@ func (r Rcon) listen(timeout time.Duration, respChan chan<- string, errChan chan
 			respChan <- sb.String()
 			return
 		default:
-			rlen, err := r.conn.ReadUntil(time.Now().Add(timeout), respBuf)
+			c, ok := r.conn.(*UDPConn)
+			if !ok {
+				errChan <- errors.New("connection is not a UDPConn")
+				return
+			}
+			err := c.conn.SetReadDeadline(time.Now().Add(timeout))
+			if err != nil {
+				errChan <- fmt.Errorf("error setting read deadline: %w", err)
+				return
+			}
+			rlen, err := r.conn.Read(respBuf)
 			if err != nil {
 				e, ok := err.(net.Error)
 				if ok {
@@ -131,10 +153,8 @@ func (r Rcon) listen(timeout time.Duration, respChan chan<- string, errChan chan
 				}
 			}
 
-			if rlen > len(r.response.Header()) {
-				if bytes.HasPrefix(respBuf, r.response.Header()) {
-					sb.Write(respBuf[len(r.response.Header()):rlen])
-				}
+			if r.response.isValid(respBuf[:rlen]) {
+				sb.WriteString(r.response.decode(respBuf[:rlen]))
 			}
 		}
 	}

request.go

@@ -0,0 +1,35 @@
+package q3rcon
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+)
+
+const (
+	bufSz         = 1024
+	requestHeader = "\xff\xff\xff\xffrcon"
+)
+
+type request struct {
+	password string
+	buf      *bytes.Buffer
+}
+
+func newRequest(password string) request {
+	return request{
+		password: password,
+		buf:      bytes.NewBuffer(make([]byte, 0, bufSz)),
+	}
+}
+
+func (r request) encode(cmd string) ([]byte, error) {
+	if cmd == "" {
+		return nil, errors.New("command cannot be empty")
+	}
+
+	r.buf.Reset()
+	r.buf.WriteString(requestHeader)
+	r.buf.WriteString(fmt.Sprintf(" %s %s", r.password, cmd))
+	return r.buf.Bytes(), nil
+}

response.go

@@ -0,0 +1,21 @@
+package q3rcon
+
+import "bytes"
+
+const (
+	responseHeader = "\xff\xff\xff\xffprint\n"
+)
+
+type response struct{}
+
+func newResponse() response {
+	return response{}
+}
+
+func (r response) isValid(buf []byte) bool {
+	return len(buf) > len(responseHeader) && bytes.HasPrefix(buf, []byte(responseHeader))
+}
+
+func (r response) decode(buf []byte) string {
+	return string(buf[len(responseHeader):])
+}