➕ Added password validator

vendor/github.com/lane-c-wagner/go-password-validator/validate.go

@@ -0,0 +1,65 @@
+package passwordvalidator
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+// Validate returns nil if the password has greater than or
+// equal to the minimum entropy. If not, an error is returned
+// that explains how the password can be strengthened. This error
+// is safe to show the client
+func Validate(password string, minEntropy float64) error {
+	entropy := getEntropy(password)
+	if entropy >= minEntropy {
+		return nil
+	}
+
+	hasSpecial := false
+	hasLower := false
+	hasUpper := false
+	hasDigits := false
+	for _, c := range password {
+		if containsRune(specialChars, c) {
+			hasSpecial = true
+			continue
+		}
+		if containsRune(lowerChars, c) {
+			hasLower = true
+			continue
+		}
+		if containsRune(upperChars, c) {
+			hasUpper = true
+			continue
+		}
+		if containsRune(digitsChars, c) {
+			hasDigits = true
+			continue
+		}
+	}
+
+	allMessages := []string{}
+
+	if !hasSpecial {
+		allMessages = append(allMessages, "including special characters")
+	}
+	if !hasLower {
+		allMessages = append(allMessages, "using lowercase letters")
+	}
+	if !hasUpper {
+		allMessages = append(allMessages, "using uppercase letters")
+	}
+	if !hasDigits {
+		allMessages = append(allMessages, "using numbers")
+	}
+
+	if len(allMessages) > 0 {
+		return fmt.Errorf(
+			"Insecure password. Try %v or using a longer password",
+			strings.Join(allMessages, ", "),
+		)
+	}
+
+	return errors.New("Insecure password. Try using a longer password")
+}