core/kg/model/user.go

package model

import (
	"net/mail"
	"regexp"
	"strings"
	"unicode"

	"github.com/pkg/errors"
)

const (
	userNameMaxLength  = 64
	userNameMinLength  = 1
	userEmailMaxLength = 128
)

// User contains the details about the user.
type User struct {
	ID                 string `json:"id"`
	CreateAt           int64  `json:"create_at,omitempty"`
	UpdateAt           int64  `json:"update_at,omitempty"`
	DeleteAt           int64  `json:"delete_at"`
	Username           string `json:"username"`
	Password           string `json:"password,omitempty"`
	Email              string `json:"email"`
	EmailVerified      bool   `json:"email_verified,omitempty"`
	FirstName          string `json:"first_name"`
	LastName           string `json:"last_name"`
	LastPasswordUpdate int64  `json:"last_password_update,omitempty"`
}

// IsValid validates the user and returns an error if it isn't configured
// correctly.
func (u *User) IsValid() error {
	if !isValidID(u.ID) {
		return invalidUserError("id", "")
	}

	if u.CreateAt == 0 {
		return invalidUserError("create_at", u.ID)
	}

	if u.UpdateAt == 0 {
		return invalidUserError("update_at", u.ID)
	}

	if !isValidUsername(u.Username) {
		return invalidUserError("username", u.ID)
	}

	if !isValidEmail(u.Email) {
		return invalidUserError("email", u.ID)
	}

	return nil
}

func isValidID(value string) bool {
	if len(value) != 26 {
		return false
	}

	for _, r := range value {
		if !unicode.IsLetter(r) && !unicode.IsNumber(r) {
			return false
		}
	}

	return true
}

func invalidUserError(fieldName string, userID string) error {
	return errors.Errorf("Invalid User field: %s; id: %s", fieldName, userID)
}

func isValidUsername(s string) bool {
	if len(s) < userNameMinLength || len(s) > userNameMaxLength {
		return false
	}

	validUsernameChars := regexp.MustCompile(`^[a-z0-9\.\-_]+$`)
	if !validUsernameChars.MatchString(s) {
		return false
	}

	return true
}

func isValidEmail(email string) bool {
	if len(email) > userEmailMaxLength || email == "" {
		return false
	}
	if !isLower(email) {
		return false
	}

	if addr, err := mail.ParseAddress(email); err != nil {
		return false
	} else if addr.Name != "" {
		// mail.ParseAddress accepts input of the form "Billy Bob <billy@example.com>" which we don't allow
		return false
	}

	return true
}

func isLower(s string) bool {
	return strings.ToLower(s) == s
}