fix: harden exploration data flow

backend/internal/logic/dataset/service.go

@@ -350,6 +350,13 @@ func (s *Service) DepositItem(userID uint, itemIdentity, projectIdentity string)
 	if body == "" {
 		body = strings.TrimSpace(item.Summary)
 	}
+	if item.ImageURL != "" {
+		if body != "" {
+			body = "![文章图片](" + item.ImageURL + ")\n\n" + body
+		} else {
+			body = "![文章图片](" + item.ImageURL + ")"
+		}
+	}
 	if item.URL != "" {
 		if body != "" {
 			body += "\n\n"
@@ -464,10 +471,12 @@ func storeFeedItems(tx *gorm.DB, source models.SaDatasetSource, items []FeedItem
 	inserted := 0
 	for _, input := range items {
 		externalID := input.ExternalID
+		itemURL := resolveFeedReference(source.URL, input.URL)
+		imageURL := resolveFeedReference(source.URL, input.ImageURL)
 		item := models.SaDatasetItem{
 			SourceID: source.ID, ExternalID: &externalID,
 			Title: input.Title, Summary: input.Summary, Content: input.Content,
-			URL: input.URL, ImageURL: input.ImageURL,
+			URL: itemURL, ImageURL: imageURL,
 			Status: "unread", PublishedAt: input.PublishedAt,
 		}
 		result := tx.Clauses(clause.OnConflict{
@@ -478,10 +487,58 @@ func storeFeedItems(tx *gorm.DB, source models.SaDatasetSource, items []FeedItem
 			return inserted, result.Error
 		}
 		inserted += int(result.RowsAffected)
+		if result.RowsAffected == 0 {
+			updates := map[string]any{
+				"title": item.Title,
+			}
+			if item.Summary != "" {
+				updates["summary"] = item.Summary
+			}
+			if item.Content != "" {
+				updates["content"] = item.Content
+			}
+			if item.URL != "" {
+				updates["url"] = item.URL
+			}
+			if item.ImageURL != "" {
+				updates["image_url"] = item.ImageURL
+			}
+			if item.PublishedAt != nil {
+				updates["published_at"] = item.PublishedAt
+			}
+			if err := tx.Model(&models.SaDatasetItem{}).
+				Where("source_id = ? AND external_id = ?", source.ID, externalID).
+				Updates(updates).Error; err != nil {
+				return inserted, err
+			}
+		}
 	}
 	return inserted, nil
 }
 
+func resolveFeedReference(baseURL, reference string) string {
+	reference = strings.TrimSpace(reference)
+	if reference == "" {
+		return ""
+	}
+	parsedReference, err := url.Parse(reference)
+	if err != nil {
+		return ""
+	}
+	if !parsedReference.IsAbs() {
+		parsedBase, err := url.Parse(baseURL)
+		if err != nil {
+			return ""
+		}
+		parsedReference = parsedBase.ResolveReference(parsedReference)
+	}
+	resolved := parsedReference.String()
+	if !validHTTPURL(resolved) {
+		return ""
+	}
+	return truncateRunes(resolved, 2048)
+}
+
 func truncateResult(value string) string {
 	return truncateRunes(value, 2000)
 }