🚀 DAY 5 OF LAUNCH WEEK: Introducing Socket Firewall Enterprise.Learn more →
Socket
Book a DemoInstallSign in
Socket
Book a DemoInstallSign in

github.com/clevergo/captchas

Package Overview
Dependencies
Alerts
File Explorer

Advanced tools

License
Socket logo

Install Socket

Detect and block malicious and high-risk dependencies

Install

github.com/clevergo/captchas

Source
Go
Version
v0.3.2
Version published
Created
Source

Captchas

Build Status Coverage Status GoDoc Go Report Card Release

Base64 Captchas Manager, supports multiple drivers(digit, math, audio, string, chinese etc.) and stores(memory, redis, memcached etc.).

Usage

Preview: http://129.204.189.159:10000/.

$ cd example
$ go run main.go

Quick Start

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"text/template"

	"github.com/clevergo/captchas"
	"github.com/clevergo/captchas/drivers"
	"github.com/clevergo/captchas/memstore"
)

var (
	store   = memstore.New()              // memory store.
	driver  = drivers.NewDigit()          // digit driver.
	manager = captchas.New(store, driver) // manager
	tmpl    = template.Must(template.New("captcha").Parse(`
<html>
<body>
<form action="/validate" method="POST">
	<input name="captcha">
	{{ .captcha.HTMLField "captcha_id" }}
	<input type="submit" value="Submit">
</form>
</body>
</html>
	`))
)

func main() {
	http.HandleFunc("/generate", generate)
	http.HandleFunc("/validate", validate)
	log.Println(http.ListenAndServe(":8080", http.DefaultServeMux))
}

// generates a new captcha
func generate(w http.ResponseWriter, r *http.Request) {
	captcha, err := manager.Generate()
	if err != nil {
		http.Error(w, err.Error(), 500)
                return
	}

	// returns JSON data.
	if r.URL.Query().Get("format") == "json" {
		v := map[string]string{
			"captcha_id":   captcha.ID(),             // captcha ID.
			"captcha_data": captcha.EncodeToString(), // base64 encode string.
		}
		data, _ := json.Marshal(v)
		w.Write(data)
		return
	}

	// render captcha via template.
	tmpl.Execute(w, map[string]interface{}{
		"captcha": captcha,
	})

}

// validates a captcha.
func validate(w http.ResponseWriter, r *http.Request) {
	captchaID := r.PostFormValue("captcha_id")
	captcha := r.PostFormValue("captcha")

	// verify
	if err := manager.Verify(captchaID, captcha, true); err != nil {
		io.WriteString(w, fmt.Sprintf("captcha is invalid: %s", err.Error()))
		return
	}

	io.WriteString(w, "valid")
}

Drivers

import "github.com/clevergo/captchas/drivers"

Digit

// all options are optional.
opts := []drivers.DigitOption{
	drivers.DigitHeight(50),
	drivers.DigitWidth(120),
	drivers.DigitLength(6),
	drivers.DigitMaxSkew(0.8),
	drivers.DigitDotCount(80),
}
driver := drivers.NewDigit(opts...)

Audio

// all options are optional.
opts := []drivers.AudioOption{
	drivers.AudioLangauge("en"),
	drivers.AudioLength(6),
}
driver := drivers.NewAudio(opts...)

Math

// all options are optional.
opts := []drivers.MathOption{
	drivers.MathHeight(50),
	drivers.MathWidth(120),
	drivers.MathNoiseCount(0),
	drivers.MathFonts([]string{}),
	drivers.MathBGColor(&color.RGBA{}),
}
driver := drivers.NewMath(opts...)

String

// all options are optional.
opts := []drivers.StringOption{
	drivers.StringHeight(50),
	drivers.StringWidth(120),
	drivers.StringLength(4),
	drivers.StringNoiseCount(0),
	drivers.StringFonts([]string{}),
	drivers.StringSource("abcdefghijklmnopqrstuvwxyz"),
	drivers.StringBGColor(&color.RGBA{}),
}
driver := drivers.NewString(opts...)

Chinese

// all options are optional.
opts := []drivers.ChineseOption{
	drivers.ChineseHeight(50),
	drivers.ChineseWidth(120),
	drivers.ChineseLength(4),
	drivers.ChineseNoiseCount(0),
	drivers.ChineseFonts([]string{"wqy-microhei.ttc"}),
	drivers.ChineseSource("零一二三四五六七八九十"),
	drivers.ChineseBGColor(&color.RGBA{}),
}
driver := drivers.NewChinese(opts...)

Stores

Memory

import "github.com/clevergo/captchas/memstore"

store := memstore.New(
	memstore.Expiration(10*time.Minute), // captcha expiration, optional.
	memstore.GCInterval(time.Minute), // garbage collection interval to delete expired captcha, optional.
)

Inspired by scs.memstore.

Redis

import (
    "github.com/clevergo/captchas/redisstore"
    "github.com/go-redis/redis/v7"
)

// redis client.
client := redis.NewClient(&redis.Options{
	Addr: "localhost:6379",
})
store := redisstore.New(
	client,
	redisstore.Expiration(expiration), // captcha expiration, optional.
	redisstore.Prefix("caotchas"), // redis key prefix, optional.
)

Memcached

import (
	"github.com/bradfitz/gomemcache/memcache"
	"github.com/clevergo/captchas/memcachedstore"
)

// client.
client := memcache.New("localhost:11211")
store := memcachedstore.New(
	client,
	memcachedstore.Expiration(int32(600)), // captcha expiration, optional.
	memcachedstore.Prefix("captchas"),     // key prefix, optional.
)

FAQs

Package last updated on 09 Mar 2020

Did you know?

Socket

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.

Install

Related posts

The Changelog Podcast: Practical Steps to Stay Safe on npm

Security News

The Changelog Podcast: Practical Steps to Stay Safe on npm

Learn the essential steps every developer should take to stay secure on npm and reduce exposure to supply chain attacks.

By Sarah Gooding  -  Oct 31, 2025