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base64Captcha

package module
v1.4.0 Latest Latest
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This package is not in the latest version of its module.

 Go to latest Published: Sep 17, 2026 License: Apache-2.0 Imports: 24 Imported by: 0

README

A flexible and various captcha package

Test Ask DeepWiki Go Report Card GoDoc Build Status codecov stability-stable Foundation

Fork 说明

本仓库 fork 自 mojocn/base64Captcha，模块路径已由 github.com/mojocn/base64Captcha 改为 github.com/verystar/base64Captcha：

import "github.com/verystar/base64Captcha"

与上游相比的主要差异：

  • 移除中文验证码驱动 DriverChinese 与中文字体 wqy-microhei.ttc
  • 移除音频验证码（DriverAudio 驱动与 sounds.go）
  • 内置字体精简为 actionj.ttf、Flim-Flam.ttf
  • 字体渲染由已归档的 github.com/golang/freetype 迁移至官方 golang.org/x/image
  • Go 版本要求升级到 1.25

Base64captcha supports any unicode character and can easily be customized to support Math Korean Japanese Russian Arabic etc.

1. 📖📖📖 Doc & Demo

2. 🚀🚀🚀 Quick start

2.1 🎬🎬🎬 Use history version

Tag v1.2.2

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/verystar/base64Captcha

For Gopher from mainland China without VPN go get golang.org/x/image failure solution:

  • go version >= 1.25
  • 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:

  1. Build-in Driver Digit
  2. Build-in Driver String
  3. Build-in Driver Math
// 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) 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/verystar/base64Captcha"
	"log"
	"net/http"
)

//configJsonBody json request body.
type configJsonBody struct {
	Id           string
	CaptchaType  string
	VerifyValue  string
	DriverString *base64Captcha.DriverString
	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 "string":
		driver = param.DriverString.ConvertFonts()
	case "math":
		driver = param.DriverMath.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

3. 🎨🎨🎨 Customization

You can customize your captcha display image by implementing interface driver and interface item.

There are some example for your reference.

  1. DriverMath
  2. ItemChar

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).

Documentation

Overview

Package base64Captcha supports digits, numbers,alphabet, arithmetic and digit-alphabet captcha. base64Captcha is used for fast 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

Index

Constants

View Source 
const (

	//TxtNumbers chacters for numbers.
	TxtNumbers = "012346789"
	//TxtAlphabet characters for alphabet.
	TxtAlphabet = "ABCDEFGHJKMNOQRSTUVXYZabcdefghjkmnoqrstuvxyz"
	//TxtSimpleCharaters simple numbers and alphabet
	TxtSimpleCharaters = "13467ertyiadfhjkxcvbnERTYADFGHJKXCVBN"

	//MimeTypeImage output base64 mine-type.
	MimeTypeImage = "image/png"
	//Emoji is a source string for randTxt
	Emoji = "" /* 268-byte string literal not displayed */
)
View Source 
const (
	//OptionShowHollowLine shows hollow line
	OptionShowHollowLine = 2
	//OptionShowSlimeLine shows slime line
	OptionShowSlimeLine = 4
	//OptionShowSineLine shows sine line
	OptionShowSineLine = 8
)

Variables

View Source 
var (
	// GCLimitNumber The number of captchas created that triggers garbage collection used by default store.
	GCLimitNumber = 10240
	// Expiration time of captchas used by default store.
	Expiration = 10 * time.Minute
	// DefaultMemStore is a shared storage for captchas, generated by New function.
	DefaultMemStore = NewMemoryStore(GCLimitNumber, Expiration)
)
View Source 
var DefaultDriverDigit = NewDriverDigit(80, 240, 5, 0.7, 80)

DefaultDriverDigit is a default driver of digit

View Source 
var DefaultEmbeddedFonts = NewEmbeddedFontsStorage(defaultEmbeddedFontsFS)

Functions

func RandColor 

func RandColor() color.RGBA

RandColor get random color. 生成随机颜色.

func RandDeepColor 

func RandDeepColor() color.RGBA

RandDeepColor get random deep color. 随机生成深色系.

func RandLightColor 

func RandLightColor() color.RGBA

RandLightColor get random ligth color. 随机生成浅色.

func RandText 

func RandText(size int, sourceChars string) string

RandText creates random text of given size.

func RandomId 

func RandomId() string

RandomId returns a new random id key string.

Types

type Captcha 

type Captcha struct {
	Driver Driver
	Store  Store
}

Captcha captcha basic information.

func NewCaptcha 

func NewCaptcha(driver Driver, store Store) *Captcha

NewCaptcha creates a captcha instance from driver and store

func (*Captcha) Generate 

func (c *Captcha) Generate() (id, b64s, answer string, err error)

Generate generates a random id, base64 image string or an error if any

func (*Captcha) Verify 

func (c *Captcha) Verify(id, answer string, clear bool) (match bool)

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.

type Driver 

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)
}

Driver captcha interface for captcha engine to to write staff

type DriverDigit 

type DriverDigit struct {
	// Height png height in pixel.
	Height int
	// Width Captcha png width in pixel.
	Width int
	// DefaultLen Default number of digits in captcha solution.
	Length int
	// MaxSkew max absolute skew factor of a single digit.
	MaxSkew float64
	// DotCount Number of background circles.
	DotCount int
}

DriverDigit config for captcha-engine-digit.

func NewDriverDigit 

func NewDriverDigit(height int, width int, length int, maxSkew float64, dotCount int) *DriverDigit

NewDriverDigit creates a driver of digit

func (*DriverDigit) DrawCaptcha 

func (d *DriverDigit) DrawCaptcha(content string) (item Item, err error)

DrawCaptcha creates digit captcha item

func (*DriverDigit) GenerateIdQuestionAnswer 

func (d *DriverDigit) GenerateIdQuestionAnswer() (id, q, a string)

GenerateIdQuestionAnswer creates captcha content and answer

func (*DriverDigit) GenerateSpecificIdQuestionAnswer 

func (d *DriverDigit) GenerateSpecificIdQuestionAnswer(mId string) (id, q, a string)

GenerateIdQuestionAnswer creates captcha content and answer

type DriverLanguage 

type DriverLanguage struct {
	// Height png height in pixel.
	Height int
	// Width Captcha png width in pixel.
	Width int

	//NoiseCount text noise count.
	NoiseCount int

	//ShowLineOptions := OptionShowHollowLine | OptionShowSlimeLine | OptionShowSineLine .
	ShowLineOptions int

	//Length random string length.
	Length int

	//BgColor captcha image background color (optional)
	BgColor *color.RGBA

	//Fonts loads by name see fonts.go's comment
	Fonts        []*opentype.Font
	LanguageCode string
	// contains filtered or unexported fields
}

DriverLanguage generates language unicode by lanuage

func NewDriverLanguage 

func NewDriverLanguage(height int, width int, noiseCount int, showLineOptions int, length int, bgColor *color.RGBA, fontsStorage FontsStorage, fonts []*opentype.Font, languageCode string) *DriverLanguage

NewDriverLanguage creates a driver

func (*DriverLanguage) DrawCaptcha 

func (d *DriverLanguage) DrawCaptcha(content string) (item Item, err error)

DrawCaptcha creates item

func (*DriverLanguage) GenerateIdQuestionAnswer 

func (d *DriverLanguage) GenerateIdQuestionAnswer() (id, content, answer string)

GenerateIdQuestionAnswer creates content and answer

type DriverMath 

type DriverMath struct {
	//Height png height in pixel.
	Height int

	// Width Captcha png width in pixel.
	Width int

	//NoiseCount text noise count.
	NoiseCount int

	//ShowLineOptions := OptionShowHollowLine | OptionShowSlimeLine | OptionShowSineLine .
	ShowLineOptions int

	//BgColor captcha image background color (optional)
	BgColor *color.RGBA

	//Fonts loads by name see fonts.go's comment
	Fonts []string
	// contains filtered or unexported fields
}

DriverMath captcha config for captcha math

func NewDriverMath 

func NewDriverMath(height int, width int, noiseCount int, showLineOptions int, bgColor *color.RGBA, fontsStorage FontsStorage, fonts []string) *DriverMath

NewDriverMath creates a driver of math

func (*DriverMath) ConvertFonts 

func (d *DriverMath) ConvertFonts() *DriverMath

ConvertFonts loads fonts from names

func (*DriverMath) DrawCaptcha 

func (d *DriverMath) DrawCaptcha(question string) (item Item, err error)

DrawCaptcha creates math captcha item

func (*DriverMath) GenerateIdQuestionAnswer 

func (d *DriverMath) GenerateIdQuestionAnswer() (id, question, answer string)

GenerateIdQuestionAnswer creates id,captcha content and answer

type DriverString 

type DriverString struct {
	// Height png height in pixel.
	Height int

	// Width Captcha png width in pixel.
	Width int

	//NoiseCount text noise count.
	NoiseCount int

	//ShowLineOptions := OptionShowHollowLine | OptionShowSlimeLine | OptionShowSineLine .
	ShowLineOptions int

	//Length random string length.
	Length int

	//Source is a unicode which is the rand string from.
	Source string

	//BgColor captcha image background color (optional)
	BgColor *color.RGBA

	//Fonts loads by name see fonts.go's comment
	Fonts []string
	// contains filtered or unexported fields
}

DriverString captcha config for captcha-engine-characters.

func NewDriverString 

func NewDriverString(height int, width int, noiseCount int, showLineOptions int, length int, source string, bgColor *color.RGBA, fontsStorage FontsStorage, fonts []string) *DriverString

NewDriverString creates driver

func (*DriverString) ConvertFonts 

func (d *DriverString) ConvertFonts() *DriverString

ConvertFonts loads fonts by names

func (*DriverString) DrawCaptcha 

func (d *DriverString) DrawCaptcha(content string) (item Item, err error)

DrawCaptcha draws captcha item

func (*DriverString) GenerateIdQuestionAnswer 

func (d *DriverString) GenerateIdQuestionAnswer() (id, content, answer string)

GenerateIdQuestionAnswer creates id,content and answer

type EmbeddedFontsStorage 

type EmbeddedFontsStorage struct {
	// contains filtered or unexported fields
}

func NewEmbeddedFontsStorage 

func NewEmbeddedFontsStorage(fs embed.FS) *EmbeddedFontsStorage

func (*EmbeddedFontsStorage) LoadFontByName 

func (s *EmbeddedFontsStorage) LoadFontByName(name string) *opentype.Font

func (*EmbeddedFontsStorage) LoadFontsByNames 

func (s *EmbeddedFontsStorage) LoadFontsByNames(assetFontNames []string) []*opentype.Font

LoadFontsByNames import fonts from dir, preserving the given order.

type FontsStorage 

type FontsStorage interface {
	// LoadFontByName returns the font from the storage
	LoadFontByName(name string) *opentype.Font

	// LoadFontsByNames returns multiple fonts from storage
	LoadFontsByNames(assetFontNames []string) []*opentype.Font
}

FontsStorage interface for working with fonts

type Item 

type Item interface {
	//WriteTo writes to a writer
	WriteTo(w io.Writer) (n int64, err error)
	//EncodeB64string encodes as base64 string
	EncodeB64string() string
}

Item is captcha item interface

type ItemChar 

type ItemChar struct {
	// contains filtered or unexported fields
}

ItemChar captcha item of unicode characters

func NewItemChar 

func NewItemChar(w int, h int, bgColor color.RGBA) *ItemChar

NewItemChar creates a captcha item of characters

func (*ItemChar) BinaryEncoding 

func (item *ItemChar) BinaryEncoding() []byte

BinaryEncoding encodes an image to PNG and returns a byte slice.

func (*ItemChar) EncodeB64string 

func (item *ItemChar) EncodeB64string() string

EncodeB64string encodes an image to base64 string

func (*ItemChar) WriteTo 

func (item *ItemChar) WriteTo(w io.Writer) (int64, error)

WriteTo writes captcha character in png format into the given io.Writer, and returns the number of bytes written and an error if any.

type ItemDigit 

type ItemDigit struct {
	*image.Paletted
	// contains filtered or unexported fields
}

ItemDigit digits captcha Struct

func NewItemDigit 

func NewItemDigit(width int, height int, dotCount int, maxSkew float64) *ItemDigit

NewItemDigit create a instance of item-digit

func (*ItemDigit) EncodeB64string 

func (m *ItemDigit) EncodeB64string() string

EncodeB64string encodes an image to base64 string

func (*ItemDigit) EncodeBinary 

func (m *ItemDigit) EncodeBinary() []byte

EncodeBinary encodes an image to PNG and returns a byte slice.

func (*ItemDigit) WriteTo 

func (m *ItemDigit) WriteTo(w io.Writer) (int64, error)

WriteTo writes captcha character in png format into the given io.Writer, and returns the number of bytes written and an error if any.

type Store 

type Store interface {
	// Set sets the digits for the captcha id.
	Set(id string, value string) error

	// 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
}

Store An object implementing Store interface can be registered with SetCustomStore function to handle storage and retrieval of captcha ids and solutions for them, replacing the default memory store.

It is the responsibility of an object to delete expired and used captchas when necessary (for example, the default memory store collects them in Set method after the certain amount of captchas has been stored.)

func NewMemoryStore 

func NewMemoryStore(collectNum int, expiration time.Duration) Store

NewMemoryStore returns a new standard memory store for captchas with the given collection threshold and expiration time (duration). The returned store must be registered with SetCustomStore to replace the default one.

type StoreSyncMap 

type StoreSyncMap struct {
	// contains filtered or unexported fields
}

StoreSyncMap use sync.Map as store

func NewStoreSyncMap 

func NewStoreSyncMap(liveTime time.Duration) *StoreSyncMap

NewStoreSyncMap new a instance

func (StoreSyncMap) Get 

func (s StoreSyncMap) Get(id string, clear bool) string

Set a string value

func (StoreSyncMap) Set 

func (s StoreSyncMap) Set(id string, value string)

Get get a string value

func (StoreSyncMap) Verify 

func (s StoreSyncMap) Verify(id, answer string, clear bool) bool

Verify check a string value

Source Files

View all Source files

Directories

Path Synopsis
example of HTTP server that uses the captcha package.
 example of HTTP server that uses the captcha package.

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