移动端和 PC 端登录页都加了“图形验证码

2026-06-12 21:16:08 +08:00
parent 8cfb63a3e7
commit f6ea3e29a6
13 changed files with 456 additions and 84 deletions
@@ -0,0 +1,113 @@
+package captcha
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"html"
+	"math/big"
+	"strings"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+var (
+	ErrDependencyUnavailable = errors.New("captcha dependency unavailable")
+	ErrInvalid               = errors.New("captcha invalid")
+)
+
+type Item struct {
+	CaptchaID string `json:"captcha_id"`
+	Image     string `json:"image"`
+	ExpiresIn int64  `json:"expires_in"`
+}
+
+func Generate(ctx context.Context, redisClient *redis.Client, namespace string, ttl time.Duration) (*Item, error) {
+	if redisClient == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	captchaID, err := randomToken(16)
+	if err != nil {
+		return nil, err
+	}
+	code, err := randomCaptchaCode(4)
+	if err != nil {
+		return nil, err
+	}
+	if err := redisClient.Set(ctx, key(namespace, captchaID), strings.ToUpper(code), ttl).Err(); err != nil {
+		return nil, err
+	}
+	return &Item{
+		CaptchaID: captchaID,
+		Image:     imageDataURL(code),
+		ExpiresIn: int64(ttl.Seconds()),
+	}, nil
+}
+
+func Verify(ctx context.Context, redisClient *redis.Client, namespace string, captchaID string, captchaCode string) error {
+	if redisClient == nil {
+		return ErrDependencyUnavailable
+	}
+	captchaID = strings.TrimSpace(captchaID)
+	captchaCode = strings.TrimSpace(captchaCode)
+	if captchaID == "" || captchaCode == "" {
+		return ErrInvalid
+	}
+
+	redisKey := key(namespace, captchaID)
+	stored, err := redisClient.Get(ctx, redisKey).Result()
+	if errors.Is(err, redis.Nil) {
+		return ErrInvalid
+	}
+	if err != nil {
+		return err
+	}
+	_ = redisClient.Del(ctx, redisKey).Err()
+	if strings.ToUpper(captchaCode) != stored {
+		return ErrInvalid
+	}
+	return nil
+}
+
+func key(namespace string, id string) string {
+	namespace = strings.Trim(strings.ToLower(strings.TrimSpace(namespace)), ":")
+	if namespace == "" {
+		namespace = "default"
+	}
+	return "captcha:" + namespace + ":" + id
+}
+
+func randomToken(length int) (string, error) {
+	buf := make([]byte, length)
+	if _, err := rand.Read(buf); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(buf), nil
+}
+
+func randomCaptchaCode(length int) (string, error) {
+	const alphabet = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ"
+	result := make([]byte, length)
+	for i := range result {
+		n, err := rand.Int(rand.Reader, big.NewInt(int64(len(alphabet))))
+		if err != nil {
+			return "", err
+		}
+		result[i] = alphabet[n.Int64()]
+	}
+	return string(result), nil
+}
+
+func imageDataURL(code string) string {
+	safeCode := html.EscapeString(strings.ToUpper(code))
+	svg := fmt.Sprintf(`<svg xmlns="http://www.w3.org/2000/svg" width="132" height="44" viewBox="0 0 132 44">
+<rect width="132" height="44" rx="8" fill="#eef5f7"/>
+<path d="M8 32 C32 2, 62 52, 124 12" stroke="#0f766e" stroke-width="2" fill="none" opacity=".28"/>
+<path d="M10 13 C42 42, 86 0, 122 31" stroke="#2563eb" stroke-width="2" fill="none" opacity=".22"/>
+<text x="66" y="29" text-anchor="middle" font-family="Menlo,Consolas,monospace" font-size="24" font-weight="700" letter-spacing="4" fill="#111827">%s</text>
+</svg>`, safeCode)
+	return "data:image/svg+xml;base64," + base64.StdEncoding.EncodeToString([]byte(svg))
+}