refactor(backend): 添加 service 缓存端口

backend/internal/repository/identity_cache.go

@@ -0,0 +1,47 @@
+package repository
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"sub2api/internal/service/ports"
+
+	"github.com/redis/go-redis/v9"
+)
+
+const (
+	fingerprintKeyPrefix = "fingerprint:"
+	fingerprintTTL       = 24 * time.Hour
+)
+
+type identityCache struct {
+	rdb *redis.Client
+}
+
+func NewIdentityCache(rdb *redis.Client) ports.IdentityCache {
+	return &identityCache{rdb: rdb}
+}
+
+func (c *identityCache) GetFingerprint(ctx context.Context, accountID int64) (*ports.Fingerprint, error) {
+	key := fmt.Sprintf("%s%d", fingerprintKeyPrefix, accountID)
+	val, err := c.rdb.Get(ctx, key).Result()
+	if err != nil {
+		return nil, err
+	}
+	var fp ports.Fingerprint
+	if err := json.Unmarshal([]byte(val), &fp); err != nil {
+		return nil, err
+	}
+	return &fp, nil
+}
+
+func (c *identityCache) SetFingerprint(ctx context.Context, accountID int64, fp *ports.Fingerprint) error {
+	key := fmt.Sprintf("%s%d", fingerprintKeyPrefix, accountID)
+	val, err := json.Marshal(fp)
+	if err != nil {
+		return err
+	}
+	return c.rdb.Set(ctx, key, val, fingerprintTTL).Err()
+}