add

internal/infrastructure/external/captcha/captcha_service.go

@@ -0,0 +1,134 @@
+package captcha
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"time"
+
+	"github.com/alibabacloud-go/tea/tea"
+	captcha20230305 "github.com/alibabacloud-go/captcha-20230305/client"
+	openapi "github.com/alibabacloud-go/darabonba-openapi/v2/client"
+)
+
+var (
+	ErrCaptchaVerifyFailed   = errors.New("图形验证码校验失败")
+	ErrCaptchaConfig         = errors.New("验证码配置错误")
+	ErrCaptchaEncryptMissing = errors.New("加密模式需要配置 EncryptKey（控制台 ekey）")
+)
+
+// CaptchaConfig 阿里云验证码配置
+type CaptchaConfig struct {
+	AccessKeyID     string
+	AccessKeySecret string
+	EndpointURL     string
+	SceneID         string
+	// EncryptKey 加密模式使用的密钥（控制台 ekey，Base64 编码的 32 字节），用于生成 EncryptedSceneId
+	EncryptKey string
+}
+
+// CaptchaService 阿里云验证码服务
+type CaptchaService struct {
+	config CaptchaConfig
+}
+
+// NewCaptchaService 创建验证码服务实例
+func NewCaptchaService(config CaptchaConfig) *CaptchaService {
+	return &CaptchaService{
+		config: config,
+	}
+}
+
+// Verify 验证滑块验证码
+func (s *CaptchaService) Verify(captchaVerifyParam string) error {
+	if captchaVerifyParam == "" {
+		return ErrCaptchaVerifyFailed
+	}
+
+	if s.config.AccessKeyID == "" || s.config.AccessKeySecret == "" {
+		return ErrCaptchaConfig
+	}
+
+	clientCfg := &openapi.Config{
+		AccessKeyId:     tea.String(s.config.AccessKeyID),
+		AccessKeySecret: tea.String(s.config.AccessKeySecret),
+	}
+	clientCfg.Endpoint = tea.String(s.config.EndpointURL)
+
+	client, err := captcha20230305.NewClient(clientCfg)
+	if err != nil {
+		return errors.Join(ErrCaptchaConfig, err)
+	}
+
+	req := &captcha20230305.VerifyIntelligentCaptchaRequest{
+		SceneId:            tea.String(s.config.SceneID),
+		CaptchaVerifyParam: tea.String(captchaVerifyParam),
+	}
+
+	resp, err := client.VerifyIntelligentCaptcha(req)
+	if err != nil {
+		return errors.Join(ErrCaptchaVerifyFailed, err)
+	}
+
+	if resp.Body == nil || !tea.BoolValue(resp.Body.Result.VerifyResult) {
+		return ErrCaptchaVerifyFailed
+	}
+
+	return nil
+}
+
+// GetEncryptedSceneId 生成加密场景 ID（EncryptedSceneId），供前端加密模式初始化验证码使用。
+// 算法：AES-256-CBC，明文 sceneId&timestamp&expireTime，密钥为控制台 ekey（Base64 解码后 32 字节）。
+// expireTimeSec 有效期为 1～86400 秒。
+func (s *CaptchaService) GetEncryptedSceneId(expireTimeSec int) (string, error) {
+	if expireTimeSec <= 0 || expireTimeSec > 86400 {
+		return "", fmt.Errorf("expireTimeSec 必须在 1～86400 之间")
+	}
+	if s.config.EncryptKey == "" {
+		return "", ErrCaptchaEncryptMissing
+	}
+	if s.config.SceneID == "" {
+		return "", ErrCaptchaConfig
+	}
+
+	keyBytes, err := base64.StdEncoding.DecodeString(s.config.EncryptKey)
+	if err != nil || len(keyBytes) != 32 {
+		return "", errors.Join(ErrCaptchaConfig, fmt.Errorf("EncryptKey 必须为 Base64 编码的 32 字节"))
+	}
+
+	plaintext := fmt.Sprintf("%s&%d&%d", s.config.SceneID, time.Now().Unix(), expireTimeSec)
+	plainBytes := []byte(plaintext)
+	plainBytes = pkcs7Pad(plainBytes, aes.BlockSize)
+
+	block, err := aes.NewCipher(keyBytes)
+	if err != nil {
+		return "", errors.Join(ErrCaptchaConfig, err)
+	}
+
+	iv := make([]byte, aes.BlockSize)
+	if _, err := io.ReadFull(rand.Reader, iv); err != nil {
+		return "", err
+	}
+
+	mode := cipher.NewCBCEncrypter(block, iv)
+	ciphertext := make([]byte, len(plainBytes))
+	mode.CryptBlocks(ciphertext, plainBytes)
+
+	result := make([]byte, len(iv)+len(ciphertext))
+	copy(result, iv)
+	copy(result[len(iv):], ciphertext)
+	return base64.StdEncoding.EncodeToString(result), nil
+}
+
+func pkcs7Pad(data []byte, blockSize int) []byte {
+	n := blockSize - (len(data) % blockSize)
+	pad := make([]byte, n)
+	for i := range pad {
+		pad[i] = byte(n)
+	}
+	return append(data, pad...)
+}