JJJJJJJerk / base64Captcha

Base64 Encoding Captcha for golang RESTful application

Base64 Encoding Captcha for RESTful application

Package base64Captcha create digits captcha encoded by base64 png image base64Captcha is used for rapid 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 Image for RESTful Application

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

CSS Image Embedding Example

div.image {
  background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADIA...);
}

HTML Image Embedding Example

<img alt="Embedded Image" src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADIA..." />

Documentation

• English
• 中文文档

Playground Powered by Vuejs+elementUI+Axios

Quick Start

Download and Install

go get -u github.com/mojocn/base64Captcha

use base64Captcha quick start a API server

package main

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

// base64Captcha verify http handler
func captchaVerifyHandle(w http.ResponseWriter, r *http.Request) {
	//parse request parameters
	r.ParseForm()
	formData := r.Form
	captchaId := formData.Get("captchaId")
	captchaDigits := formData.Get("captchaDigits")

	//verify the captcha
	verifyResult := base64Captcha.VerifyCaptcha(captchaId, captchaDigits)

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

// base64Captcha create http handler
func generateCaptchaHandler(w http.ResponseWriter, r *http.Request) {
	//parse request parameters

	r.ParseForm()
	formData := r.Form
	captchaId := formData.Get("captchaId")
	DotCount, _ := strconv.Atoi(formData.Get("DotCount"))
	MaxSkew, _ := strconv.ParseFloat(formData.Get("MaxSkew"), 64)
	PngWidth, _ := strconv.Atoi(formData.Get("PngWidth"))
	PngHeight, _ := strconv.Atoi(formData.Get("PngHeight"))
	DefaultLen, _ := strconv.Atoi(formData.Get("DefaultLen"))

	//create base64 encoding captcha
	base64Png := base64Captcha.GenerateCaptchaPngBase64String(captchaId, PngWidth, PngHeight, DotCount, DefaultLen, MaxSkew)
	//or you can do this
	//base64Png := captcha.GenerateCaptchaPngBase64StringDefault(captchaId)

	//set json response
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	body := map[string]interface{}{"code": 1, "data": base64Png, "msg": "success", "debug": formData}
	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 localhost:777")
	if err := http.ListenAndServe(":777", nil); err != nil {
		log.Fatal(err)
	}
}

base64Captcha package function

• func GenerateCaptchaPngBase64String(identifier string, pngWidth, pngHeight, DotCount, digitsLen int, maxSkew float64) string return base64-png-captcha
• func GenerateCaptchaPngBase64StringDefault(identifier string) string default settings width=240 height=70 dot-count=20 digits-len=6 skew-factor=0.7
• func VerifyCaptcha(identifier, digits string) bool verify the captcha-png-numbers 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;
           proxy_set_header Host $http_host;
           proxy_pass http://127.0.0.1:777;
        }
        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

License

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