A flexible and various captcha package
Base64captcha supports any unicode character and can easily be customized to support Math Chinese Korean Japanese Russian Arabic etc.
1. ??? Doc & Demo
2. ??? Quick start
2.1 ??? Use history version
go get github.com/mojocn/base64Captcha@v1.2.2
or edit your go.mod file to
github.com/mojocn/base64Captcha@v1.2.2
2.2 ??? Download package
go get -u github.com/mojocn/base64Captcha
For Gopher from mainland China without VPN go get golang.org/x/image failure solution:
- go version > 1.11
- set env
GOPROXY=https://goproxy.io
2.3 ??? How to code with base64Captcha
2.3.1 ??? Implement Store interface or use build-in memory store
type Store interface {
// Set sets the digits for the captcha id.
Set(id string, value string)
// Get returns stored digits for the captcha id. Clear indicates
// whether the captcha must be deleted from the store.
Get(id string, clear bool) string
//Verify captcha's answer directly
Verify(id, answer string, clear bool) bool
}
2.3.2 ??? Implement Driver interface or use one of build-in drivers
There are some build-in drivers:
// Driver captcha interface for captcha engine to to write staff
type Driver interface {
//DrawCaptcha draws binary item
DrawCaptcha(content string) (item Item, err error)
//GenerateIdQuestionAnswer creates rand id, content and answer
GenerateIdQuestionAnswer() (id, q, a string)
}
2.3.3 ??? Core code captcha.go
captcha.go is the entry of base64Captcha which is quite simple.
package base64Captcha
import (
"math/rand"
"time"
)
func init() {
//init rand seed
rand.Seed(time.Now().UnixNano())
}
// Captcha captcha basic information.
type Captcha struct {
Driver Driver
Store Store
}
//NewCaptcha creates a captcha instance from driver and store
func NewCaptcha(driver Driver, store Store) *Captcha {
return &Captcha{Driver: driver, Store: store}
}
//Generate generates a random id, base64 image string or an error if any
func (c *Captcha) Generate() (id, b64s string, err error) {
id,content, answer := c.Driver.GenerateIdQuestionAnswer()
item, err := c.Driver.DrawCaptcha(content)
if err != nil {
return "", "", err
}
c.Store.Set(id, answer)
b64s = item.EncodeB64string()
return
}
//Verify by a given id key and remove the captcha value in store,
//return boolean value.
//if you has multiple captcha instances which share a same store.
//You may want to call `store.Verify` method instead.
func (c *Captcha) Verify(id, answer string, clear bool) (match bool) {
match = c.Store.Get(id, clear) == answer
return
}
2.3.4 ??? Generate Base64(image/audio) string
func (c *Captcha) Generate() (id, b64s string, err error) {
id,content, answer := c.Driver.GenerateIdQuestionAnswer()
item, err := c.Driver.DrawCaptcha(content)
if err != nil {
return "", "", err
}
c.Store.Set(id, answer)
b64s = item.EncodeB64string()
return
}
2.3.5 ??? Verify Answer
//if you has multiple captcha instances which shares a same store. You may want to use `store.Verify` method instead.
//Verify by given id key and remove the captcha value in store, return boolean value.
func (c *Captcha) Verify(id, answer string, clear bool) (match bool) {
match = c.Store.Get(id, clear) == answer
return
}
2.3.6 ??? Full Example
// 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
DriverAudio *base64Captcha.DriverAudio
DriverString *base64Captcha.DriverString
DriverChinese *base64Captcha.DriverChinese
DriverMath *base64Captcha.DriverMath
DriverDigit *base64Captcha.DriverDigit
}
var store = base64Captcha.DefaultMemStore
// base64Captcha create http handler
func generateCaptchaHandler(w http.ResponseWriter, r *http.Request) {
//parse request parameters
decoder := json.NewDecoder(r.Body)
var param configJsonBody
err := decoder.Decode(¶m)
if err != nil {
log.Println(err)
}
defer r.Body.Close()
var driver base64Captcha.Driver
//create base64 encoding captcha
switch param.CaptchaType {
case "audio":
driver = param.DriverAudio
case "string":
driver = param.DriverString.ConvertFonts()
case "math":
driver = param.DriverMath.ConvertFonts()
case "chinese":
driver = param.DriverChinese.ConvertFonts()
default:
driver = param.DriverDigit
}
c := base64Captcha.NewCaptcha(driver, store)
id, b64s, err := c.Generate()
body := map[string]interface{}{"code": 1, "data": b64s, "captchaId": id, "msg": "success"}
if err != nil {
body = map[string]interface{}{"code": 0, "msg": err.Error()}
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
json.NewEncoder(w).Encode(body)
}
// base64Captcha verify http handler
func captchaVerifyHandle(w http.ResponseWriter, r *http.Request) {
//parse request json body
decoder := json.NewDecoder(r.Body)
var param configJsonBody
err := decoder.Decode(¶m)
if err != nil {
log.Println(err)
}
defer r.Body.Close()
//verify the captcha
body := map[string]interface{}{"code": 0, "msg": "failed"}
if store.Verify(param.Id, param.VerifyValue, true) {
body = map[string]interface{}{"code": 1, "msg": "ok"}
}
//set json response
w.Header().Set("Content-Type", "application/json; charset=utf-8")
json.NewEncoder(w).Encode(body)
}
//start a net/http server
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 :8777")
if err := http.ListenAndServe(":8777", nil); err != nil {
log.Fatal(err)
}
}
3. ??? Customization
You can customize your captcha display image by implementing interface driver
and interface item.
There are some example for your reference.
You can even design the captcha struct to whatever you prefer.
4. ??? Thanks
5. ??? Licence
base64Captcha source code is licensed under the Apache Licence, Version 2.0
(http://www.apache.org/licenses/LICENSE-2.0.html).