big update: added reactions, groups, media share

server/internal/api/media.go

@@ -0,0 +1,172 @@
+package api
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"mime"
+	"net/http"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"messenger/internal/media"
+	"messenger/internal/store"
+)
+
+const maxUploadBytes = 25 << 20 // 25 MiB
+
+type mediaJSON struct {
+	ID          int64  `json:"id"`
+	Filename    string `json:"filename"`
+	ContentType string `json:"content_type"`
+	Size        int64  `json:"size"`
+	URL         string `json:"url"`
+	ThumbURL    string `json:"thumb_url,omitempty"`
+}
+
+func toMediaJSON(m *store.Media) mediaJSON {
+	out := mediaJSON{
+		ID:          m.ID,
+		Filename:    m.Filename,
+		ContentType: m.ContentType,
+		Size:        m.Size,
+		URL:         fmt.Sprintf("/api/v1/media/%d", m.ID),
+	}
+	if m.ThumbKey != "" {
+		out.ThumbURL = fmt.Sprintf("/api/v1/media/%d/thumb", m.ID)
+	}
+	return out
+}
+
+// uploadMedia accepts a multipart file and stores it, generating a thumbnail
+// for images. Media is accessible to any authenticated user; conversation
+// membership checks are a documented family-scale simplification.
+func (h *apiHandler) uploadMedia(w http.ResponseWriter, r *http.Request) {
+	userID, _ := userIDFrom(r.Context())
+	r.Body = http.MaxBytesReader(w, r.Body, maxUploadBytes+1<<20)
+
+	file, header, err := r.FormFile("file")
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "missing file field")
+		return
+	}
+	defer file.Close()
+
+	data, err := io.ReadAll(file)
+	if err != nil {
+		writeError(w, http.StatusBadRequest, "failed to read file")
+		return
+	}
+	if len(data) == 0 {
+		writeError(w, http.StatusBadRequest, "empty file")
+		return
+	}
+	if len(data) > maxUploadBytes {
+		writeError(w, http.StatusBadRequest, "file too large (max 25 MiB)")
+		return
+	}
+
+	contentType := header.Header.Get("Content-Type")
+	if contentType == "" || strings.HasPrefix(contentType, "application/octet-stream") {
+		contentType = http.DetectContentType(data)
+	}
+
+	id := randomHex(16)
+	ext := filepath.Ext(header.Filename)
+	storageKey := fmt.Sprintf("u%d/%s%s", userID, id, ext)
+	if err := h.media.Save(r.Context(), storageKey, bytes.NewReader(data)); err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to store file")
+		return
+	}
+
+	thumbKey := ""
+	if media.IsImage(contentType) {
+		thumb, err := media.Generate(r.Context(), bytes.NewReader(data), contentType, 512)
+		if err != nil {
+			writeError(w, http.StatusInternalServerError, "failed to generate thumbnail")
+			return
+		}
+		if thumb != nil {
+			thumbKey = fmt.Sprintf("u%d/%s_thumb.jpg", userID, id)
+			if err := h.media.Save(r.Context(), thumbKey, bytes.NewReader(thumb)); err != nil {
+				writeError(w, http.StatusInternalServerError, "failed to store thumbnail")
+				return
+			}
+		}
+	}
+
+	created, err := h.store.CreateMedia(r.Context(), store.Media{
+		UploaderID:  userID,
+		Filename:    header.Filename,
+		ContentType: contentType,
+		Size:        int64(len(data)),
+		StorageKey:  storageKey,
+		ThumbKey:    thumbKey,
+	})
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "internal server error")
+		return
+	}
+	writeJSON(w, http.StatusCreated, toMediaJSON(created))
+}
+
+func (h *apiHandler) downloadMedia(w http.ResponseWriter, r *http.Request) {
+	h.serveStoredFile(w, r, func(m *store.Media) (string, string, int64) {
+		return m.StorageKey, m.ContentType, m.Size
+	})
+}
+
+func (h *apiHandler) downloadThumb(w http.ResponseWriter, r *http.Request) {
+	h.serveStoredFile(w, r, func(m *store.Media) (string, string, int64) {
+		if m.ThumbKey == "" {
+			return "", "", 0
+		}
+		return m.ThumbKey, "image/jpeg", 0
+	})
+}
+
+func (h *apiHandler) serveStoredFile(w http.ResponseWriter, r *http.Request, pick func(*store.Media) (key, contentType string, size int64)) {
+	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
+	if err != nil || id <= 0 {
+		writeError(w, http.StatusBadRequest, "invalid media id")
+		return
+	}
+	m, err := h.store.GetMediaByID(r.Context(), id)
+	if err != nil {
+		writeError(w, http.StatusNotFound, "media not found")
+		return
+	}
+	key, contentType, size := pick(m)
+	if key == "" {
+		writeError(w, http.StatusNotFound, "thumbnail not available")
+		return
+	}
+	rc, err := h.media.Open(r.Context(), key)
+	if err != nil {
+		writeError(w, http.StatusNotFound, "file not found")
+		return
+	}
+	defer rc.Close()
+
+	w.Header().Set("Content-Type", contentType)
+	w.Header().Set("Cache-Control", "private, max-age=31536000, immutable")
+	if ext := filepath.Ext(m.Filename); ext != "" {
+		if cd := mime.TypeByExtension(ext); cd == "" {
+			w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=%q", m.Filename))
+		}
+	}
+	if size > 0 {
+		w.Header().Set("Content-Length", strconv.FormatInt(size, 10))
+	}
+	w.WriteHeader(http.StatusOK)
+	_, _ = io.Copy(w, rc)
+}
+
+func randomHex(n int) string {
+	buf := make([]byte, n)
+	_, _ = rand.Read(buf)
+	return hex.EncodeToString(buf)
+}