add auth layer

auth/htpasswd.go

@@ -0,0 +1,41 @@
+package auth
+
+import (
+	"bufio"
+	"os"
+	"strings"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+type HtpasswdAuth struct {
+	path string
+}
+
+func NewHtpasswdAuth(path string) *HtpasswdAuth {
+	return &HtpasswdAuth{path: path}
+}
+
+func (h *HtpasswdAuth) Authenticate(user, pass string) error {
+	f, err := os.Open(h.path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		parts := strings.SplitN(line, ":", 2)
+		if len(parts) != 2 {
+			continue
+		}
+		if parts[0] == user {
+			if bcrypt.CompareHashAndPassword([]byte(parts[1]), []byte(pass)) == nil {
+				return nil
+			}
+			return ErrAuthFailed
+		}
+	}
+	return ErrAuthFailed
+}