feat: add emoji reaction support for files

- Implement `ReactionService` to manage file reactions in the database.
- Add `POST /d/{boxID}/f/{fileID}/react` endpoint to handle user reactions.
- Add `GET /emoji/{pack}/{file}` endpoint to serve custom emoji assets.
- Support loading custom emoji packs dynamically from the data directory.
- Update README with instructions on configuring emoji reaction packs.

backend/libs/services/reactions.go

@@ -0,0 +1,166 @@
+package services
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"os"
+	"sort"
+	"strings"
+	"time"
+
+	"go.etcd.io/bbolt"
+)
+
+var reactionsBucket = []byte("file_reactions")
+
+type ReactionService struct {
+	db *bbolt.DB
+}
+
+type FileReaction struct {
+	BoxID       string    `json:"boxId"`
+	FileID      string    `json:"fileId"`
+	EmojiID     string    `json:"emojiId"`
+	VisitorHash string    `json:"visitorHash"`
+	CreatedAt   time.Time `json:"createdAt"`
+}
+
+type ReactionSummary struct {
+	EmojiID string `json:"emojiId"`
+	Count   int    `json:"count"`
+}
+
+func NewReactionService(db *bbolt.DB) (*ReactionService, error) {
+	if err := db.Update(func(tx *bbolt.Tx) error {
+		_, err := tx.CreateBucketIfNotExists(reactionsBucket)
+		return err
+	}); err != nil {
+		return nil, err
+	}
+	return &ReactionService{db: db}, nil
+}
+
+func (s *ReactionService) Add(boxID, fileID, visitorID, emojiID string) ([]ReactionSummary, error) {
+	boxID = strings.TrimSpace(boxID)
+	fileID = strings.TrimSpace(fileID)
+	visitorHash := reactionVisitorHash(visitorID)
+	emojiID = strings.TrimSpace(emojiID)
+	if boxID == "" || fileID == "" || visitorHash == "" || emojiID == "" {
+		return nil, errors.New("missing reaction data")
+	}
+
+	reaction := FileReaction{
+		BoxID:       boxID,
+		FileID:      fileID,
+		EmojiID:     emojiID,
+		VisitorHash: visitorHash,
+		CreatedAt:   time.Now().UTC(),
+	}
+	data, err := json.Marshal(reaction)
+	if err != nil {
+		return nil, err
+	}
+
+	key := reactionKey(boxID, fileID, visitorHash)
+	if err := s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(reactionsBucket)
+		if bucket.Get([]byte(key)) != nil {
+			return os.ErrExist
+		}
+		return bucket.Put([]byte(key), data)
+	}); err != nil {
+		return nil, err
+	}
+	return s.SummaryForFile(boxID, fileID)
+}
+
+func (s *ReactionService) SummaryForBox(boxID, visitorID string) (map[string][]ReactionSummary, map[string]bool, error) {
+	visitorHash := reactionVisitorHash(visitorID)
+	summaries := make(map[string]map[string]int)
+	viewerReacted := make(map[string]bool)
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(reactionsBucket)
+		if bucket == nil {
+			return nil
+		}
+		return bucket.ForEach(func(_, data []byte) error {
+			var reaction FileReaction
+			if err := json.Unmarshal(data, &reaction); err != nil {
+				return err
+			}
+			if reaction.BoxID != boxID {
+				return nil
+			}
+			if summaries[reaction.FileID] == nil {
+				summaries[reaction.FileID] = make(map[string]int)
+			}
+			summaries[reaction.FileID][reaction.EmojiID]++
+			if visitorHash != "" && reaction.VisitorHash == visitorHash {
+				viewerReacted[reaction.FileID] = true
+			}
+			return nil
+		})
+	})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	result := make(map[string][]ReactionSummary, len(summaries))
+	for fileID, counts := range summaries {
+		result[fileID] = reactionCountsToSummaries(counts)
+	}
+	return result, viewerReacted, nil
+}
+
+func (s *ReactionService) SummaryForFile(boxID, fileID string) ([]ReactionSummary, error) {
+	counts := make(map[string]int)
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(reactionsBucket)
+		if bucket == nil {
+			return nil
+		}
+		return bucket.ForEach(func(_, data []byte) error {
+			var reaction FileReaction
+			if err := json.Unmarshal(data, &reaction); err != nil {
+				return err
+			}
+			if reaction.BoxID == boxID && reaction.FileID == fileID {
+				counts[reaction.EmojiID]++
+			}
+			return nil
+		})
+	})
+	if err != nil {
+		return nil, err
+	}
+	return reactionCountsToSummaries(counts), nil
+}
+
+func reactionCountsToSummaries(counts map[string]int) []ReactionSummary {
+	summaries := make([]ReactionSummary, 0, len(counts))
+	for emojiID, count := range counts {
+		summaries = append(summaries, ReactionSummary{EmojiID: emojiID, Count: count})
+	}
+	sort.Slice(summaries, func(i, j int) bool {
+		if summaries[i].Count == summaries[j].Count {
+			return summaries[i].EmojiID < summaries[j].EmojiID
+		}
+		return summaries[i].Count > summaries[j].Count
+	})
+	return summaries
+}
+
+func reactionKey(boxID, fileID, visitorHash string) string {
+	return boxID + "\x00" + fileID + "\x00" + visitorHash
+}
+
+func reactionVisitorHash(visitorID string) string {
+	visitorID = strings.TrimSpace(visitorID)
+	if visitorID == "" {
+		return ""
+	}
+	sum := sha256.Sum256([]byte(visitorID))
+	return hex.EncodeToString(sum[:])
+}

backend/libs/services/upload.go

@@ -137,6 +137,9 @@ func NewUploadService(maxUploadSize int64, dataDir, baseURL string, logger *slog
 	if err := os.MkdirAll(dbDir, 0o755); err != nil {
 		return nil, err
 	}
+	if err := os.MkdirAll(filepath.Join(dataDir, "emoji"), 0o755); err != nil {
+		return nil, err
+	}
 
 	db, err := bbolt.Open(filepath.Join(dbDir, "warpbox.bbolt"), 0o600, &bbolt.Options{Timeout: time.Second})
 	if err != nil {
@@ -957,6 +960,10 @@ func randomID(byteCount int) string {
 	return base64.RawURLEncoding.EncodeToString(data)
 }
 
+func RandomPublicToken(byteCount int) string {
+	return randomID(byteCount)
+}
+
 func hashPassword(password string) (string, string) {
 	salt := randomID(18)
 	return salt, passwordHash(salt, password)