init

auth.go

@@ -0,0 +1,155 @@
+package gost
+
+import (
+	"bufio"
+	"io"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Authenticator is an interface for user authentication.
+type Authenticator interface {
+	Authenticate(user, password string) bool
+}
+
+// LocalAuthenticator is an Authenticator that authenticates client by local key-value pairs.
+type LocalAuthenticator struct {
+	kvs     map[string]string
+	period  time.Duration
+	stopped chan struct{}
+	mux     sync.RWMutex
+}
+
+// NewLocalAuthenticator creates an Authenticator that authenticates client by local infos.
+func NewLocalAuthenticator(kvs map[string]string) *LocalAuthenticator {
+	return &LocalAuthenticator{
+		kvs:     kvs,
+		stopped: make(chan struct{}),
+	}
+}
+
+// Authenticate checks the validity of the provided user-password pair.
+func (au *LocalAuthenticator) Authenticate(user, password string) bool {
+	if au == nil {
+		return true
+	}
+
+	au.mux.RLock()
+	defer au.mux.RUnlock()
+
+	if len(au.kvs) == 0 {
+		return true
+	}
+
+	v, ok := au.kvs[user]
+	return ok && (v == "" || password == v)
+}
+
+// Add adds a key-value pair to the Authenticator.
+func (au *LocalAuthenticator) Add(k, v string) {
+	au.mux.Lock()
+	defer au.mux.Unlock()
+	if au.kvs == nil {
+		au.kvs = make(map[string]string)
+	}
+	au.kvs[k] = v
+}
+
+// Reload parses config from r, then live reloads the Authenticator.
+func (au *LocalAuthenticator) Reload(r io.Reader) error {
+	var period time.Duration
+	kvs := make(map[string]string)
+
+	if r == nil || au.Stopped() {
+		return nil
+	}
+
+	// splitLine splits a line text by white space.
+	// A line started with '#' will be ignored, otherwise it is valid.
+	split := func(line string) []string {
+		if line == "" {
+			return nil
+		}
+		line = strings.Replace(line, "\t", " ", -1)
+		line = strings.TrimSpace(line)
+
+		if strings.IndexByte(line, '#') == 0 {
+			return nil
+		}
+
+		var ss []string
+		for _, s := range strings.Split(line, " ") {
+			if s = strings.TrimSpace(s); s != "" {
+				ss = append(ss, s)
+			}
+		}
+		return ss
+	}
+
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		line := scanner.Text()
+		ss := split(line)
+		if len(ss) == 0 {
+			continue
+		}
+
+		switch ss[0] {
+		case "reload": // reload option
+			if len(ss) > 1 {
+				period, _ = time.ParseDuration(ss[1])
+			}
+		default:
+			var k, v string
+			k = ss[0]
+			if len(ss) > 1 {
+				v = ss[1]
+			}
+			kvs[k] = v
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+
+	au.mux.Lock()
+	defer au.mux.Unlock()
+
+	au.period = period
+	au.kvs = kvs
+
+	return nil
+}
+
+// Period returns the reload period.
+func (au *LocalAuthenticator) Period() time.Duration {
+	if au.Stopped() {
+		return -1
+	}
+
+	au.mux.RLock()
+	defer au.mux.RUnlock()
+
+	return au.period
+}
+
+// Stop stops reloading.
+func (au *LocalAuthenticator) Stop() {
+	select {
+	case <-au.stopped:
+	default:
+		close(au.stopped)
+	}
+}
+
+// Stopped checks whether the reloader is stopped.
+func (au *LocalAuthenticator) Stopped() bool {
+	select {
+	case <-au.stopped:
+		return true
+	default:
+		return false
+	}
+}