Function StoreShortLink

db_controller/db_controller.go:414–463

StoreShortLink stores a short link in the database with optimized collision handling

(shortCode string, originalURL string)

// StoreShortLink stores a short link in the database with optimized collision handling
func StoreShortLink(shortCode string, originalURL string) error {
	shortLink := ShortLink{
		ShortCode:   shortCode,
		OriginalURL: originalURL,
	}

	// Try direct insert first with DO NOTHING on conflict
	result := db.Clauses(clause.OnConflict{
		DoNothing: true,
	}).Create(&shortLink)

	if result.Error != nil {
		return result.Error
	}

	// If no rows were affected, either there was a shortCode collision or the URL exists
	if result.RowsAffected == 0 {
		// Check if URL already exists
		var existing ShortLink
		if err := db.Where("original_url = ?", originalURL).First(&existing).Error; err == nil {
			return nil // URL exists, reuse existing shortcode
		}

		// Handle collision with simple numeric suffixes
		for i := 0; i < 10; i++ {
			newCode := fmt.Sprintf("%s%d", shortCode[:7], i)
			shortLink.ShortCode = newCode
			result = db.Clauses(clause.OnConflict{
				DoNothing: true,
			}).Create(&shortLink)

			if result.Error == nil && result.RowsAffected > 0 {
				return nil
			}
		}

		// If simple attempts failed, try timestamp-based suffix
		newCode := fmt.Sprintf("%s%x", shortCode[:7], time.Now().UnixNano()%16)
		shortLink.ShortCode = newCode
		result = db.Clauses(clause.OnConflict{
			DoNothing: true,
		}).Create(&shortLink)

		if result.Error == nil && result.RowsAffected > 0 {
			return nil
		}
	}

	return nil
}

// GetOriginalURL retrieves the original URL from the database using the short code
func GetOriginalURL(shortCode string) (string, error) {