Initial commit (code only without large binaries)

EdgeNode/internal/waf/captcha_generator.go

@@ -0,0 +1,71 @@
+// Copyright 2023 GoEdge CDN goedge.cdn@gmail.com. All rights reserved. Official site: https://goedge.cn .
+
+package waf
+
+import (
+	"bytes"
+	"github.com/dchest/captcha"
+	"github.com/iwind/TeaGo/rands"
+	"io"
+	"time"
+)
+
+// CaptchaGenerator captcha generator
+type CaptchaGenerator struct {
+	store captcha.Store
+}
+
+func NewCaptchaGenerator() *CaptchaGenerator {
+	return &CaptchaGenerator{
+		store: captcha.NewMemoryStore(100_000, 5*time.Minute),
+	}
+}
+
+// NewCaptcha create new captcha
+func (this *CaptchaGenerator) NewCaptcha(length int) (captchaId string) {
+	captchaId = rands.HexString(16)
+
+	if length <= 0 || length > 20 {
+		length = 4
+	}
+
+	this.store.Set(captchaId, captcha.RandomDigits(length))
+	return
+}
+
+// WriteImage write image to front writer
+func (this *CaptchaGenerator) WriteImage(w io.Writer, id string, width, height int) error {
+	var d = this.store.Get(id, false)
+	if d == nil {
+		return captcha.ErrNotFound
+	}
+	_, err := captcha.NewImage(id, d, width, height).WriteTo(w)
+	return err
+}
+
+// Verify user input
+func (this *CaptchaGenerator) Verify(id string, digits string) bool {
+	var countDigits = len(digits)
+	if countDigits == 0 {
+		return false
+	}
+	var value = this.store.Get(id, true)
+	if len(value) != countDigits {
+		return false
+	}
+
+	var nb = make([]byte, countDigits)
+	for i := 0; i < countDigits; i++ {
+		var d = digits[i]
+		if d >= '0' && d <= '9' {
+			nb[i] = d - '0'
+		}
+	}
+
+	return bytes.Equal(nb, value)
+}
+
+// Get captcha data
+func (this *CaptchaGenerator) Get(id string) []byte {
+	return this.store.Get(id, false)
+}