go get -u github.com/mojocn/base64Captcha

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,
    IsShowHollowLine:  false,
    IsShowNoiseDot:   false,
    IsShowNoiseText:  false,
    IsShowSlimeLine:  false,
    IsShowSineLine:   false,
    CaptchaLen:     6,
  }
  //create a audio captcha.
  idKeyA, capA := base64Captcha.GenerateCaptcha("", configA)
  //以base64编码
  base64stringA := base64Captcha.CaptchaWriteToBase64Encoding(capA)
  //create a characters captcha.
  idKeyC, capC := base64Captcha.GenerateCaptcha("", configC)
  //以base64编码
  base64stringC := base64Captcha.CaptchaWriteToBase64Encoding(capC)
  //create a digits captcha.
  idKeyD, capD := base64Captcha.GenerateCaptcha("", configD)
  //以base64编码
  base64stringD := base64Captcha.CaptchaWriteToBase64Encoding(capD)
   
  fmt.Println(idKeyA, base64stringA, "\n")
  fmt.Println(idKeyC, base64stringC, "\n")
  fmt.Println(idKeyD, base64stringD, "\n")
}

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

// 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
}
 
var configC = base64Captcha.ConfigCharacter{
  Height:       60,
  Width:       240,
  Mode:        0,
  ComplexOfNoiseText: 0,
  ComplexOfNoiseDot: 0,
  IsShowHollowLine:  false,
  IsShowNoiseDot:   false,
  IsShowNoiseText:  false,
  IsShowSlimeLine:  false,
  IsShowSineLine:   false,
  CaptchaLen:     6,
}
 
 
// 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
  //创建base64图像验证码
 
  var config interface{}
  switch postParameters.CaptchaType {
  case "audio":
    config = postParameters.ConfigAudio
  case "character":
    config = postParameters.ConfigCharacter
  default:
    config = postParameters.ConfigDigit
  }
  captchaId, digitCap := base64Captcha.GenerateCaptcha(postParameters.Id, config)
  base64Png := base64Captcha.CaptchaWriteToBase64Encoding(digitCap)
 
  //or you can do this
  //你也可以是用默认参数 生成图像验证码
  //base64Png := captcha.GenerateCaptchaPngBase64StringDefault(captchaId)
 
  //set json response
  //设置json响应
 
  w.Header().Set("Content-Type", "application/json; charset=utf-8")
  body := map[string]interface{}{"code": 1, "data": base64Png, "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)
  }
}

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