battlemap - main.go

     1  package main
     2  
     3  import (
     4  	"bytes"
     5  	"context"
     6  	"crypto/rand"
     7  	"encoding/base64"
     8  	"flag"
     9  	"fmt"
    10  	"net"
    11  	"net/http"
    12  	"os"
    13  	"os/signal"
    14  	"path/filepath"
    15  	"time"
    16  
    17  	"vimagination.zapto.org/battlemap"
    18  	"vimagination.zapto.org/memio"
    19  	"vimagination.zapto.org/sessions"
    20  )
    21  
    22  var unauthorised = []byte(`<html>
    23  	<head>
    24  		<title>Unauthorised</title>
    25  	</head>
    26  	<body>
    27  		<h1>Not Authorised</h1>
    28  	</body>
    29  `)
    30  
    31  type Auth struct {
    32  	username    string
    33  	password    string
    34  	store       *sessions.CookieStore
    35  	sessionData memio.Buffer
    36  }
    37  
    38  func NewAuth(username, password string, sessionKey []byte) (*Auth, error) {
    39  	store, err := sessions.NewCookieStore(sessionKey, sessions.HTTPOnly(), sessions.Path("/"), sessions.Name("battlemap"), sessions.Expiry(time.Hour*24*30))
    40  	if err != nil {
    41  		return nil, fmt.Errorf("error starting Cookie Store: %w", err)
    42  	}
    43  	sessionData := make(memio.Buffer, 32)
    44  	rand.Read(sessionData)
    45  	return &Auth{
    46  		username:    username,
    47  		password:    password,
    48  		store:       store,
    49  		sessionData: sessionData,
    50  	}, nil
    51  }
    52  
    53  func (a *Auth) Auth(r *http.Request) *http.Request { return r }
    54  
    55  func (a *Auth) IsAdmin(r *http.Request) bool {
    56  	rData := a.store.Get(r)
    57  	isAdmin := bytes.Equal(rData, a.sessionData)
    58  	return isAdmin
    59  }
    60  
    61  func (a *Auth) IsUser(r *http.Request) bool {
    62  	return !a.IsAdmin(r)
    63  }
    64  
    65  func (a *Auth) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    66  	switch r.URL.Path {
    67  	case "logout":
    68  		a.store.Set(w, nil)
    69  	case "login":
    70  		username, password, _ := r.BasicAuth()
    71  		ok := username == a.username && password == a.password
    72  		if !ok {
    73  			w.Header().Set("WWW-Authenticate", "Basic realm=\"Enter Credentials\"")
    74  			w.WriteHeader(http.StatusUnauthorized)
    75  			w.Write(unauthorised)
    76  			return
    77  		}
    78  		a.store.Set(w, a.sessionData)
    79  	default:
    80  		http.NotFound(w, r)
    81  		return
    82  	}
    83  	http.Redirect(w, r, "../", http.StatusFound)
    84  }
    85  
    86  func main() {
    87  	if err := run(); err != nil {
    88  		fmt.Fprintln(os.Stderr, err)
    89  		os.Exit(1)
    90  	}
    91  }
    92  
    93  func run() error {
    94  	defaultDir, err := os.UserConfigDir()
    95  	if err != nil {
    96  		return fmt.Errorf("error getting user config dir: %w", err)
    97  	}
    98  	username := flag.String("user", "", "Username")
    99  	password := flag.String("pass", "", "Password")
   100  	p := flag.String("path", filepath.Join(defaultDir, "battlemap"), "Data Path")
   101  	port := flag.Int("port", 8080, "Web Port")
   102  	key := flag.String("key", "MDEyMzQ1Njc4OUFCQ0RFRg==", "Encryption Key (Base64: 16, 24, or 32 bytes)")
   103  	flag.Parse()
   104  	encKey, err := base64.StdEncoding.DecodeString(*key)
   105  	if err != nil {
   106  		return fmt.Errorf("error decoding encryption key: %w", err)
   107  	}
   108  	auth, err := NewAuth(*username, *password, encKey)
   109  	if err != nil {
   110  		return err
   111  	}
   112  	b, err := battlemap.New(*p, auth)
   113  	if err != nil {
   114  		return fmt.Errorf("error creating Battlemap: %w", err)
   115  	}
   116  	l, err := net.ListenTCP("tcp", &net.TCPAddr{Port: *port})
   117  	if err != nil {
   118  		return fmt.Errorf("error opening port: %w", err)
   119  	}
   120  	server := http.Server{Handler: b}
   121  	go server.Serve(l)
   122  	sc := make(chan os.Signal, 1)
   123  	signal.Notify(sc, os.Interrupt)
   124  	<-sc
   125  	signal.Stop(sc)
   126  	close(sc)
   127  	return server.Shutdown(context.Background())
   128  }
   129