smart-government-management-gateway/utils/captcha.go

// Copyright 2019 github.com. All rights reserved.
// Use of this source code is governed by github.com.

package utils

import (
	"bytes"
	"github.com/jaryhe/gopkgs/cache"
	"math/rand"
	"net/http"
	"time"

	"github.com/dchest/captcha"
	"github.com/gin-gonic/gin"
	"smart-government-management-gateway/parser"
)

var (
	CaptchaWidth = 102
	CaptchaHight = 38
)
//根据length获取随机字符串
func RandomString(length int) string {
	str := "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
	bytes := []byte(str)
	result := []byte{}
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	for i := 0; i < length; i++ {
		result = append(result, bytes[r.Intn(len(bytes))])
	}
	return string(result)
}

func Captcha(c *gin.Context, length ...int) string {
	l := captcha.DefaultLen
	if len(length) == 1 {
		l = length[0]
	}
	if len(length) == 2 {
		CaptchaWidth = length[1]
	}
	if len(length) == 3 {
		CaptchaHight = length[2]
	}
	captchaId := captcha.NewLen(l)
	SaveCaptcha(captchaId)
	return captchaId
	/*
		key := fmt.Sprintf("%d%s", time.Now().UnixNano(), RandomString(5))
		SaveCaptcha(key, captchaId)
		//session := sessions.Default(c)
		//session.Set("captcha", captchaId)
		//_ = session.Save()
		_ = Serve(c.Writer, c.Request, captchaId, ".png", "zh", false, captchaWidth, captchaHight, key)
	*/
}

func CaptchaVerify(c *gin.Context, code string, captchaId string) bool {
	if parser.Conf.RunMode == "dev" &&code == "999999" {
		return true
	}
	if captchaId == "" {
		return false
	}
	if captcha.VerifyString(captchaId, code) {
		DelCaptcha(captchaId)
		return true
	}
	return false
	/*
		session := sessions.Default(c)
		if captchaId := session.Get("captcha"); captchaId != nil {
			session.Delete("captcha")
			_ = session.Save()
			if captcha.VerifyString(captchaId.(string), code) {
				return true
			} else {
				return false
			}
		} else {
			return false
		}

	*/
}

func Serve(w http.ResponseWriter, r *http.Request, id, ext, lang string, download bool, width, height int, reload string) error {
	if id == "" {
		http.NotFound(w, r)
		return nil
	}
	if !CaptchaExist(id) {
		http.NotFound(w, r)
		return nil
	}
	captcha.Reload(id)


	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
	w.Header().Set("Pragma", "no-cache")
	w.Header().Set("Expires", "0")


	var content bytes.Buffer
	switch ext {
	case ".png":
		w.Header().Set("Content-Type", "image/png")
		_ = captcha.WriteImage2(&content, id, 120, 30)
	case ".wav":
		w.Header().Set("Content-Type", "audio/x-wav")
		_ = captcha.WriteAudio(&content, id, lang)
	default:
		return captcha.ErrNotFound
	}

	if download {
		w.Header().Set("Content-Type", "application/octet-stream")
	}
	http.ServeContent(w, r, id+ext, time.Time{}, bytes.NewReader(content.Bytes()))
	return nil
}
var captchaKey = "captcha"

func SaveCaptcha(id string) error {
	key := captchaKey + id
	_, err := cache.Redis().SetEx(key, 6000, "")
	if err != nil {
		return err
	}
	return nil
}

func DelCaptcha(id string){
	key := captchaKey + id
	cache.Redis().Del(key)
}

func CaptchaExist(id string) bool {
	key := captchaKey + id
	ret, _ := cache.Redis().Exists(key)
	if ret > 0 {
		return true
	}
	return false
}