support using duplicate checker to prevent duplicate submissions for new transaction record

pkg/duplicatechecker/in_memory_duplicate_checker.go

@@ -0,0 +1,43 @@
+package duplicatechecker
+
+import (
+	"fmt"
+
+	"github.com/patrickmn/go-cache"
+
+	"github.com/mayswind/ezbookkeeping/pkg/settings"
+)
+
+// InMemoryDuplicateChecker represents in-memory duplicate checker
+type InMemoryDuplicateChecker struct {
+	cache *cache.Cache
+}
+
+// NewInMemoryDuplicateChecker returns a new in-memory duplicate checker
+func NewInMemoryDuplicateChecker(config *settings.Config) (*InMemoryDuplicateChecker, error) {
+	checker := &InMemoryDuplicateChecker{
+		cache: cache.New(config.DuplicateSubmissionsIntervalDuration, config.InMemoryDuplicateCheckerCleanupIntervalDuration),
+	}
+
+	return checker, nil
+}
+
+// Get returns whether the same submission has been processed and related remark
+func (c *InMemoryDuplicateChecker) Get(checkerType DuplicateCheckerType, uid int64, identification string) (bool, string) {
+	existedRemark, found := c.cache.Get(c.getCacheKey(checkerType, uid, identification))
+
+	if found {
+		return true, existedRemark.(string)
+	}
+
+	return false, ""
+}
+
+// Set saves the identification and remark to in-memory cache
+func (c *InMemoryDuplicateChecker) Set(checkerType DuplicateCheckerType, uid int64, identification string, remark string) {
+	c.cache.Set(c.getCacheKey(checkerType, uid, identification), remark, cache.DefaultExpiration)
+}
+
+func (c *InMemoryDuplicateChecker) getCacheKey(checkerType DuplicateCheckerType, uid int64, identification string) string {
+	return fmt.Sprintf("%d|%d|%s", checkerType, uid, identification)
+}