Code refactoring and rename package

auth.go

@@ -0,0 +1,68 @@
+package smtpproxy
+
+import (
+	"bufio"
+	"errors"
+	"os"
+	"strings"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+var (
+	filename string
+)
+
+func AuthLoadFile(file string) error {
+	f, err := os.Open(file)
+	if err != nil {
+		return err
+	}
+	f.Close()
+
+	filename = file
+	return nil
+}
+
+func AuthReady() bool {
+	return (filename == "")
+}
+
+func AuthFetch(username string) (string, string, error) {
+	if ! AuthReady() {
+		return "", "", errors.New("Authentication file not specified. Call LoadFile() first")
+	}
+
+	file, err := os.Open(filename)
+	if err != nil {
+		return "", "", err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		parts := strings.Fields(scanner.Text())
+
+		if len(parts) != 3 {
+			continue
+		}
+
+		if strings.ToLower(username) == strings.ToLower(parts[0]) {
+			return parts[1], parts[2], nil
+		}
+	}
+
+	return "", "", errors.New("User not found")
+}
+
+func AuthCheckPassword(username string, secret string) error {
+	hash, _, err := AuthFetch(username)
+	if err != nil {
+		return err
+	}
+	if bcrypt.CompareHashAndPassword([]byte(hash), []byte(secret)) == nil {
+		return nil
+	}
+	return errors.New("Password invalid")
+}
+