--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/controllers/types.go	Tue Jul 31 11:27:45 2018 +0200
@@ -0,0 +1,146 @@
+package controllers
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"regexp"
+	"strings"
+)
+
+type (
+	Email   string
+	Country string
+	Role    string
+
+	BoundingBox struct {
+		X1 float64 `json:"x1"`
+		Y1 float64 `json:"y1"`
+		X2 float64 `json:"x2"`
+		Y2 float64 `json:"y2"`
+	}
+
+	User struct {
+		User     string       `json:"user"`
+		Role     Role         `json:"role"`
+		Password string       `json:"password,omitempty"`
+		Email    Email        `json:"email"`
+		Country  Country      `json:"country"`
+		Extent   *BoundingBox `json:"extent"`
+	}
+)
+
+var (
+	// https://stackoverflow.com/questions/201323/how-to-validate-an-email-address-using-a-regular-expression
+	emailRe = regexp.MustCompile(
+		`(?:[a-z0-9!#$%&'*+/=?^_` + "`" +
+			`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_` + "`" +
+			`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]` +
+			`|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")` +
+			`@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?` +
+			`|\[(?:(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9]))\.){3}` +
+			`(?:(2(5[0-5]|[0-4][0-9])|1[0-9][0-9]|[1-9]?[0-9])|[a-z0-9-]*[a-z0-9]` +
+			`:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]` +
+			`|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])`)
+
+	errNoEmailAddress = errors.New("Not a valid email address")
+	errNoString       = errors.New("Not a string")
+)
+
+func (e *Email) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	if !emailRe.MatchString(s) {
+		return errNoEmailAddress
+	}
+	*e = Email(s)
+	return nil
+}
+
+func (e Email) Value() (driver.Value, error) {
+	return string(e), nil
+}
+
+func (e *Email) Scan(src interface{}) (err error) {
+	if s, ok := src.(string); ok {
+		*e = Email(s)
+	} else {
+		err = errNoString
+	}
+	return
+}
+
+var (
+	validCountries = []string{
+		"AT", "BG", "DE", "HU", "HR",
+		"MD", "RO", "RS", "SK", "UA",
+	}
+	errNoValidCountry = errors.New("Not a valid country")
+)
+
+func (c *Country) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	s = strings.ToUpper(s)
+	for _, v := range validCountries {
+		if v == s {
+			*c = Country(v)
+			return nil
+		}
+	}
+	return errNoValidCountry
+}
+
+func (c Country) Value() (driver.Value, error) {
+	return string(c), nil
+}
+
+func (c *Country) Scan(src interface{}) (err error) {
+	if s, ok := src.(string); ok {
+		*c = Country(s)
+	} else {
+		err = errNoString
+	}
+	return
+}
+
+var (
+	validRoles = []string{
+		"waterway_user",
+		"waterway_admin",
+		"sys_admin",
+	}
+	errNoValidRole = errors.New("Not a valid role")
+)
+
+func (r Role) Value() (driver.Value, error) {
+	return string(r), nil
+}
+
+func (r *Role) Scan(src interface{}) (err error) {
+	if s, ok := src.(string); ok {
+		*r = Role(s)
+	} else {
+		err = errNoString
+	}
+	return
+}
+
+func (r *Role) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	s = strings.ToLower(s)
+	for _, v := range validRoles {
+		if v == s {
+			*r = Role(v)
+			return nil
+		}
+	}
+	return errNoValidRole
+}