feat(login): Captcha upgrade and add the function to ban IP addresses (#250)

utils/captcha.go

@@ -0,0 +1,48 @@
+package utils
+
+import (
+	"github.com/mojocn/base64Captcha"
+	"time"
+)
+
+var capdString = base64Captcha.NewDriverString(50, 150, 5, 10, 4, "123456789abcdefghijklmnopqrstuvwxyz", nil, nil, nil)
+
+var capdMath = base64Captcha.NewDriverMath(50, 150, 5, 10, nil, nil, nil)
+
+type B64StringCaptchaProvider struct{}
+
+func (p B64StringCaptchaProvider) Generate(ip string) (string, string, error) {
+	_, content, answer := capdString.GenerateIdQuestionAnswer()
+	return content, answer, nil
+}
+
+func (p B64StringCaptchaProvider) Expiration() time.Duration {
+	return 5 * time.Minute
+}
+func (p B64StringCaptchaProvider) Draw(content string) (string, error) {
+	item, err := capdString.DrawCaptcha(content)
+	if err != nil {
+		return "", err
+	}
+	b64str := item.EncodeB64string()
+	return b64str, nil
+}
+
+type B64MathCaptchaProvider struct{}
+
+func (p B64MathCaptchaProvider) Generate(ip string) (string, string, error) {
+	_, content, answer := capdMath.GenerateIdQuestionAnswer()
+	return content, answer, nil
+}
+
+func (p B64MathCaptchaProvider) Expiration() time.Duration {
+	return 5 * time.Minute
+}
+func (p B64MathCaptchaProvider) Draw(content string) (string, error) {
+	item, err := capdMath.DrawCaptcha(content)
+	if err != nil {
+		return "", err
+	}
+	b64str := item.EncodeB64string()
+	return b64str, nil
+}