base64Captcha

captcha of base64 image string

Programming language: Go

License: GNU General Public License v3.0 or later

Tags: Miscellaneous    

Latest version: v1.3.1

README

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

• English
• 中文文档
• Playground

2. 🚀🚀🚀 Quick start

2.1 🎬🎬🎬 Use history version

Tag v1.2.2

go get github.com/mojocn/[email protected]

or edit your go.mod file to

github.com/mojocn/[email protected]

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](interface_store.go) or use build-in memory store

• [Build-in Memory Store](store_memory.go)

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](interface_driver.go) or use one of build-in drivers

There are some build-in drivers:

1. [Build-in Driver Digit](driver_digit.go)
   
2. [Build-in Driver String](driver_string.go)
3. [Build-in Driver Math](driver_math.go)
4. [Build-in Driver Chinese](driver_chinese.go)

// 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)

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(&param)
    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(&param)
    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)
    }
}

2.3.7 Example Use Etcd as store

[captcha with etcd database as store](captcha_with_etcd_exmaple.md)

3. 🎨🎨🎨 Customization

You can customize your captcha display image by implementing [interface driver](interface_driver.go) and [interface item](interface_item.go).

There are some example for your reference.

1. [DriverMath](driver_math.go)
2. [DriverChinese](driver_chinese.go)
3. [ItemChar](item_char.go)

You can even design the [captcha struct](captcha.go) to whatever you prefer.

4. 💖💖💖 Thanks

• dchest/captha
• @slayercat
• @amzyang
• @Luckyboys
• @hi-sb

5. 🍭🍭🍭 Licence

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