motp

README

motp

A fast, thread-safe, generic in-memory OTP (One-Time Password) manager for Go with automatic cleanup.

Features

• Generic Payloads: Attach any custom metadata to your OTP using Go generics.
• Thread-Safe: Safe for concurrent access across goroutines.
• Auto-Purge: Background worker automatically cleans up expired tokens.
• Customizable: Functional options to tweak code length, character set, and cleanup intervals.

Installation

go get github.com/vladevelops/motp

Quick Start

package main

import (
	"fmt"
	"time"

	"github.com/vladevelops/motp"
)

type SessionData struct {
	UserID string
}

func main() {
	// Initialize with options
	otp := motp.NewMemoryOtp[SessionData]()

	code, err := otp.GenerateOTP(motp.OtpData[SessionData]{
		Key:        "user_123",
		Expiration: time.Now().Add(5 * time.Minute),
		Data:       SessionData{UserID: "usr_42"},
	})

	if err != nil {
		panic(err)
	}

	fmt.Println("Generated OTP:", code)

}

License

MIT

Documentation

Overview

Package motp provides a thread-safe, generic in-memory OTP manager.

It supports customizable character sets, expiration windows, and automatic background purging of stale tokens.

Basic usage:

store := motp.NewMemoryOtp[MyData]()
code, err := store.GenerateOTP(data)

Index

• Variables
• type MemoryOtp
  • func NewMemoryOtp[T any](confs ...OtpConf[T]) MemoryOtp[T]
• type OtpConf
  • func WithOTPAlphabet[T any](new_alphabet string) OtpConf[T]
  • func WithOTPCleanupTime[T any](new_time time.Duration) OtpConf[T]
  • func WithOTPLen[T any](opt_len int) OtpConf[T]
• type OtpData

Variables

var ErrCodeNotFound = errors.New("code not present")

Types

type MemoryOtp

type MemoryOtp[T any] interface {
	GenerateOTP(otp_data OtpData[T]) (code string, err error)
	CheckOTP(key, code string) (ret_otp OtpData[T], err error)
	DeleteOTP(key string) error
}

func NewMemoryOtp

func NewMemoryOtp[T any](confs ...OtpConf[T]) MemoryOtp[T]

NewMemoryOtp creates and initializes a new in-memory OTP manager.

By default, it is initialized with:

• Code length: 7 digits
• Alphabet: "0973546281" (numeric)
• Cleanup interval: 15 seconds

Custom configuration can be applied by passing functional options (confs). On creation, it automatically spins up a background goroutine to periodically purge expired OTPs from memory.

Returns a thread-safe implementation of the MemoryOtp interface.

type OtpConf

type OtpConf[T any] func(*otp_manager[T])

func WithOTPAlphabet

func WithOTPAlphabet[T any](new_alphabet string) OtpConf[T]

WithOTPAlphabet configures the set of characters used when generating OTP codes.

If not specified, the manager defaults to "0973546281".

func WithOTPCleanupTime

func WithOTPCleanupTime[T any](new_time time.Duration) OtpConf[T]

WithOTPCleanupTime sets the interval at which the background purger runs to remove expired OTPs from memory.

If not specified, the manager defaults to cleaning up every 15 seconds.

func WithOTPLen

func WithOTPLen[T any](opt_len int) OtpConf[T]

WithOTPLen sets a custom length for generated OTP codes.

If not specified, the manager defaults to generating 7-character codes.

type OtpData

type OtpData[T any] struct {
	Key        string
	Expiration time.Time
	Code       string
	Data       T
}