Base64captcha supports digits, numbers, alphabet, arithmetic, audio and digit-alphabet captcha.

Base64captcha supports digit, number, alphabet, arithmetic, audio and digit-alphabet captcha. Base64Captcha is used for fast development of RESTful APIs, web apps and backend services in Go. give a string identifier to the package and it returns with a base64-encoding-png-string

Why Base64 for RESTful Application

  Data URIs are now supported by all major browsers. IE supports embedding images since version 8 as well.
  RESTful Application returns small base64 image is more convenient.

Documentation

• English
• 中文文档

Playground Powered by Vuejs+elementUI+Axios

wav file

Quick Start

Download and Install

go get -u github.com/mojocn/base64Captcha

For Gopher from mainland China without VPN go get golang.org/x/image failure solution:

    mkdir -p $GOPATH/src/golang.org/x
    cd $GOPATH/src/golang.org/x
    git clone https://github.com/golang/image.git

Create Captcha Code

import "github.com/mojocn/base64Captcha"
func demoCodeCaptchaCreate() {
	//config struct for digits
	//数字验证码配置
	var configD = base64Captcha.ConfigDigit{
		Height:     80,
		Width:      240,
		MaxSkew:    0.7,
		DotCount:   80,
		CaptchaLen: 5,
	}
	//config struct for audio
	//声音验证码配置
	var configA = base64Captcha.ConfigAudio{
		CaptchaLen: 6,
		Language:   "zh",
	}
	//config struct for Character
	//字符,公式,验证码配置
	var configC = base64Captcha.ConfigCharacter{
		Height:             60,
		Width:              240,
		//const CaptchaModeNumber:数字,CaptchaModeAlphabet:字母,CaptchaModeArithmetic:算术,CaptchaModeNumberAlphabet:数字字母混合.
		Mode:               base64Captcha.CaptchaModeNumber,
		ComplexOfNoiseText: base64Captcha.CaptchaComplexLower,
		ComplexOfNoiseDot:  base64Captcha.CaptchaComplexLower,
		IsUseSimpleFont:    true,
		IsShowHollowLine:   false,
		IsShowNoiseDot:     false,
		IsShowNoiseText:    false,
		IsShowSlimeLine:    false,
		IsShowSineLine:     false,
		CaptchaLen:         6,
	}
	//create a audio captcha.
	//GenerateCaptcha first parameter is empty string,so the package will generate a random uuid for you.
	idKeyA, capA := base64Captcha.GenerateCaptcha("", configA)
	//write to base64 string.
	//GenerateCaptcha first parameter is empty string,so the package will generate a random uuid for you.
	base64stringA := base64Captcha.CaptchaWriteToBase64Encoding(capA)
	//create a characters captcha.
	//GenerateCaptcha first parameter is empty string,so the package will generate a random uuid for you.
	idKeyC, capC := base64Captcha.GenerateCaptcha("", configC)
	//write to base64 string.
	base64stringC := base64Captcha.CaptchaWriteToBase64Encoding(capC)
	//create a digits captcha.
	idKeyD, capD := base64Captcha.GenerateCaptcha("", configD)
	//write to base64 string.
	base64stringD := base64Captcha.CaptchaWriteToBase64Encoding(capD)

	fmt.Println(idKeyA, base64stringA, "\n")
	fmt.Println(idKeyC, base64stringC, "\n")
	fmt.Println(idKeyD, base64stringD, "\n")
}

write the captcha content of CaptchaInterfaceInstance to the httpResponseWriter.

func captchaWriterToHttpResponseWriterDemoHandler(w http.ResponseWriter, r *http.Request) {
	//config struct for Character
	var config = base64Captcha.ConfigCharacter{
		Height:             60,
		Width:              240,
		//const CaptchaModeNumber:数字,CaptchaModeAlphabet:字母,CaptchaModeArithmetic:算术,CaptchaModeNumberAlphabet:数字字母混合.
		Mode:               base64Captcha.CaptchaModeNumber,
		ComplexOfNoiseText: base64Captcha.CaptchaComplexLower,
		ComplexOfNoiseDot:  base64Captcha.CaptchaComplexLower,
		IsUseSimpleFont:    true,
		IsShowHollowLine:   false,
		IsShowNoiseDot:     false,
		IsShowNoiseText:    false,
		IsShowSlimeLine:    false,
		IsShowSineLine:     false,
		CaptchaLen:         6,
	}
	//create a captchaInterface instance.
	//GenerateCaptcha first parameter is empty string,so the package will generate a random uuid for you.
	idkey, captchaInterfaceIntance := base64Captcha.GenerateCaptcha("", config)

	//write the httpResponseCookie with idKey.
	//https://golang.org/pkg/net/http/#SetCookie

	//write the content of captcha interface instance to httpResponseWriter.
	n,err := captchaInterfaceIntance.WriteTo(w)
	ftm.Println(n,err)
}

Verify Captcha Code

import "github.com/mojocn/base64Captcha"
func verfiyCaptcha(idkey,verifyValue string){
    verifyResult := base64Captcha.VerifyCaptcha(idkey, verifyValue)
    if verifyResult {
        //success
    } else {
        //fail
    }
}

func SetCustomStore

func SetCustomStore(s Store)

SetCustomStore sets custom storage for captchas, replacing the default memory store. This function must be called before generating any captchas.

Customize Redis Store

func NewMemoryStore

func NewMemoryStore(collectNum int, expiration time.Duration) Store

NewMemoryStore returns a new standard memory store for captchas with the given collection threshold and expiration time in seconds. The returned store must be registered with SetCustomStore to replace the default one.

use base64Captcha quick start a API server

// example of HTTP server that uses the captcha package.
package main

import (
	"encoding/json"
	"fmt"
	"github.com/mojocn/base64Captcha"
	"log"
	"net/http"
)

//ConfigJsonBody json request body.
type ConfigJsonBody struct {
	Id              string
	CaptchaType     string
	VerifyValue     string
	ConfigAudio     base64Captcha.ConfigAudio
	ConfigCharacter base64Captcha.ConfigCharacter
	ConfigDigit     base64Captcha.ConfigDigit
}

// base64Captcha create http handler
func generateCaptchaHandler(w http.ResponseWriter, r *http.Request) {
	//parse request parameters
	//接收客户端发送来的请求参数
	decoder := json.NewDecoder(r.Body)
	var postParameters ConfigJsonBody
	err := decoder.Decode(&postParameters)
	if err != nil {
		log.Println(err)
	}
	defer r.Body.Close()

	//create base64 encoding captcha

	var config interface{}
	switch postParameters.CaptchaType {
	case "audio":
		config = postParameters.ConfigAudio
	case "character":
		config = postParameters.ConfigCharacter
	default:
		config = postParameters.ConfigDigit
	}
	captchaId, captcaInterfaceInstance := base64Captcha.GenerateCaptcha(postParameters.Id, config)
	base64blob := base64Captcha.CaptchaWriteToBase64Encoding(captcaInterfaceInstance)

	//or you can just write the captcha content to the httpResponseWriter.
	//before you put the captchaId into the response COOKIE.
	//captcaInterfaceInstance.WriteTo(w)

	//set json response
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	body := map[string]interface{}{"code": 1, "data": base64blob, "captchaId": captchaId, "msg": "success"}
	json.NewEncoder(w).Encode(body)
}
// base64Captcha verify http handler
func captchaVerifyHandle(w http.ResponseWriter, r *http.Request) {

	//parse request parameters
	//接收客户端发送来的请求参数
	decoder := json.NewDecoder(r.Body)
	var postParameters ConfigJsonBody
	err := decoder.Decode(&postParameters)
	if err != nil {
		log.Println(err)
	}
	defer r.Body.Close()
	//verify the captcha
	//比较图像验证码
	verifyResult := base64Captcha.VerifyCaptcha(postParameters.Id, postParameters.VerifyValue)

	//set json response
	//设置json响应
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	body := map[string]interface{}{"code": "error", "data": "验证失败", "msg": "captcha failed"}
	if verifyResult {
		body = map[string]interface{}{"code": "success", "data": "验证通过", "msg": "captcha verified"}
	}
	json.NewEncoder(w).Encode(body)
}

//start a net/http server
//启动golang net/http 服务器
func main() {

	//serve Vuejs+ElementUI+Axios Web Application
	http.Handle("/", http.FileServer(http.Dir("./static")))

	//api for create captcha
	http.HandleFunc("/api/getCaptcha", generateCaptchaHandler)

	//api for verify captcha
	http.HandleFunc("/api/verifyCaptcha", captchaVerifyHandle)

	fmt.Println("Server is at localhost:3333")
	if err := http.ListenAndServe("localhost:3333", nil); err != nil {
		log.Fatal(err)
	}
}

base64Captcha package function

• ConfigAudio captcha config for captcha-engine-audio.

  type ConfigAudio struct {
  	// CaptchaLen Default number of digits in captcha solution.
  	CaptchaLen int
  	// Language possible values for lang are "en", "ja", "ru", "zh".
  	Language string
  }
  

• ConfigDigit config for captcha-engine-digit.

  type ConfigDigit struct {
  
      // Height png height in pixel.
      // 图像验证码的高度像素.
      Height int
      // Width Captcha png width in pixel.
      // 图像验证码的宽度像素
      Width int
      // DefaultLen Default number of digits in captcha solution.
      // 默认数字验证长度6.
      CaptchaLen int
      // MaxSkew max absolute skew factor of a single digit.
      // 图像验证码的最大干扰洗漱.
      MaxSkew float64
      // DotCount Number of background circles.
      // 图像验证码干扰圆点的数量.
      DotCount int
  }
  

• ConfigCharacter captcha config for captcha-engine-characters.

  type ConfigCharacter struct {
      // Height png height in pixel.
      // 图像验证码的高度像素.
      Height int
      // Width Captcha png width in pixel.
      // 图像验证码的宽度像素
      Width int
      //Mode : base64captcha.CaptchaModeNumber=0, base64captcha.CaptchaModeAlphabet=1, base64captcha.CaptchaModeArithmetic=2, base64captcha.CaptchaModeNumberAlphabet=3.
      Mode int
      //ComplexOfNoiseText text noise count.
      ComplexOfNoiseText int
      //ComplexOfNoiseDot dot noise count.
      ComplexOfNoiseDot int
      //IsUseSimpleFont is only use this (...fonts/RitaSmith.ttf)font.
      IsUseSimpleFont bool
      //IsShowHollowLine is show hollow line.
      IsShowHollowLine bool
      //IsShowNoiseDot is show noise dot.
      IsShowNoiseDot bool
      //IsShowNoiseText is show noise text.
      IsShowNoiseText bool
      //IsShowSlimeLine is show slime line.
      IsShowSlimeLine bool
      //IsShowSineLine is show sine line.
      IsShowSineLine bool
      // CaptchaLen Default number of digits in captcha solution.
      // 默认数字验证长度6.
      CaptchaLen int
  }
  

• CaptchaInterface

  type CaptchaInterface interface {
  	//BinaryEncodeing covert to bytes
  	BinaryEncodeing() []byte
  	//WriteTo output captcha entity
  	WriteTo(w io.Writer) (n int64, err error)
  }
  

• func GenerateCaptcha(idKey string, configuration interface{}) (id string, captchaInstance CaptchaInterface) return CaptchaInterface instance.
• func CaptchaWriteToBase64Encoding(cap CaptchaInterface) string captcha base64 encodeing.
• func VerifyCaptcha(identifier, verifyValue string) bool verify the captcha content by identifierKey
• func RandomId() string Server Create Random IdentifierKey

Build and Run the Demo

cd $GOPATH/src/github.com/mojocn/captcha/examples
go run main.go

demo nginx configuration captcha.mojotv.cn.config

server {
        listen 80;
        server_name captcha.mojotv.cn;
        charset utf-8;

        location / {
            try_files /_not_exists_ @backend;
        }
        location @backend {
           proxy_set_header X-Forwarded-For $remote_addr;
           pro=xy_set_header Host $http_host;
           proxy_pass http://127.0.0.1:3333;
        }
        access_log  /home/wwwlogs/captcha.mojotv.cn.log;
}

Go to http://localhost:777

Congratulations! You've just built your first base64Captcha-APIs app. Any question you can leave a message. If you like the package please star this repo

Send Thanks

Bitcoin gratefully accepted: 13uMABdLALy9aCwRSFWZnAUM8VGn8Gsa4i

License

base64Captcha source code is licensed under the Apache Licence, Version 2.0 (http://www.apache.org/licenses/LICENSE-2.0.html).