Have got session creation working

services/imgedit/processing.go

@@ -0,0 +1,91 @@
+package imgedit
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"image"
+	"os"
+	"path/filepath"
+
+	"github.com/disintegration/imaging"
+	"lmika.dev/lmika/weiro/models"
+)
+
+func (s *Service) reprocess(ctx context.Context, session models.ImageEditSession) (imageSource, error) {
+	var img imageSource
+
+	for _, p := range session.Processors {
+		// Check if there's currently a cached image of this processor
+		cachedImageFile := filepath.Join(s.scratchDir, session.GUID, fmt.Sprintf("%v.%v", p.VersionID, session.ImageExt))
+		if s, err := os.Stat(cachedImageFile); err == nil && !s.IsDir() {
+			img = fileImageSource(cachedImageFile)
+			continue
+		}
+
+		// Need to process the image
+		var srcImg image.Image
+		if img != nil {
+			var err error
+			srcImg, err = img.image()
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		resImg, err := s.processImage(ctx, srcImg, p)
+		if err != nil {
+			return nil, err
+		}
+
+		// Cache the processed image
+		if err := imaging.Save(resImg, cachedImageFile); err != nil {
+			return nil, err
+		}
+		img = imageImageSource{resImg}
+	}
+
+	return img, nil
+}
+
+func (s *Service) processImage(ctx context.Context, srcImg image.Image, processor models.ImageEditProcessor) (image.Image, error) {
+	switch processor.Type {
+	case "copy-upload":
+		var p models.CopyUploadProps
+		if err := json.Unmarshal(processor.Props, &p); err != nil {
+			return nil, err
+		}
+
+		_, rc, err := s.uploadService.OpenUpload(ctx, p.UploadID)
+		if err != nil {
+			return nil, err
+		}
+
+		f, err := rc()
+		if err != nil {
+			return nil, err
+		}
+		defer f.Close()
+
+		return imaging.Decode(f)
+	}
+	return nil, fmt.Errorf("unknown processor type: %v", processor.Type)
+}
+
+type imageSource interface {
+	image() (image.Image, error)
+}
+
+type fileImageSource string
+
+func (f fileImageSource) image() (image.Image, error) {
+	return imaging.Open(string(f))
+}
+
+type imageImageSource struct {
+	img image.Image
+}
+
+func (i imageImageSource) image() (image.Image, error) {
+	return i.img, nil
+}

services/imgedit/service.go

@@ -0,0 +1,116 @@
+package imgedit
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"time"
+
+	"lmika.dev/lmika/weiro/models"
+	"lmika.dev/lmika/weiro/services/uploads"
+)
+
+type Service struct {
+	scratchDir    string
+	uploadService *uploads.Service
+	sessionStore  *sessionStore
+}
+
+func New(
+	uploadService *uploads.Service,
+	scratchDir string,
+) *Service {
+	return &Service{
+		scratchDir:    scratchDir,
+		uploadService: uploadService,
+		sessionStore:  &sessionStore{baseDir: scratchDir},
+	}
+}
+
+func (s *Service) LoadImageVersion(ctx context.Context, sessionID string, versionID string) (mimeType string, rw func() (io.ReadCloser, error), err error) {
+	site, user, err := s.fetchSiteAndUser(ctx)
+	if err != nil {
+		return "", nil, err
+	}
+
+	session, err := s.sessionStore.get(sessionID)
+	if err != nil {
+		return "", nil, err
+	} else if session.SiteID != site.ID || session.UserID != user.ID {
+		return "", nil, models.PermissionError
+	}
+
+	return s.sessionStore.getImage(session, versionID+"."+session.ImageExt)
+}
+
+func (s *Service) NewSession(ctx context.Context, baseUploadID int64) (models.ImageEditSession, error) {
+	site, user, err := s.fetchSiteAndUser(ctx)
+	if err != nil {
+		return models.ImageEditSession{}, err
+	}
+
+	upload, _, err := s.uploadService.OpenUpload(ctx, baseUploadID)
+	if err != nil {
+		return models.ImageEditSession{}, err
+	}
+
+	var ext string
+	switch upload.MIMEType {
+	case "image/jpeg":
+		ext = "jpg"
+	case "image/png":
+		ext = "png"
+	default:
+		return models.ImageEditSession{}, models.UnsupportedImageFormat
+	}
+
+	newSession := models.ImageEditSession{
+		GUID:         models.NewNanoID(),
+		SiteID:       site.ID,
+		UserID:       user.ID,
+		BaseUploadID: baseUploadID,
+		ImageExt:     ext,
+		CreatedAt:    time.Now().UTC(),
+		UpdatedAt:    time.Now().UTC(),
+		Processors: []models.ImageEditProcessor{
+			{
+				Type:  "copy-upload",
+				Props: mustToJSON(models.CopyUploadProps{UploadID: baseUploadID}),
+			},
+		},
+	}
+
+	newSession.RecalcVersionIDs()
+	if err := s.sessionStore.create(newSession); err != nil {
+		return models.ImageEditSession{}, err
+	}
+
+	if _, err := s.reprocess(ctx, newSession); err != nil {
+		return models.ImageEditSession{}, err
+	}
+
+	return newSession, nil
+}
+
+func (s *Service) fetchSiteAndUser(ctx context.Context) (models.Site, models.User, error) {
+	user, ok := models.GetUser(ctx)
+	if !ok {
+		return models.Site{}, models.User{}, models.UserRequiredError
+	}
+
+	site, ok := models.GetSite(ctx)
+	if !ok {
+		return models.Site{}, models.User{}, models.SiteRequiredError
+	}
+
+	if site.OwnerID != user.ID {
+		return models.Site{}, models.User{}, models.PermissionError
+	}
+
+	return site, user, nil
+}
+
+func mustToJSON(a any) json.RawMessage {
+	b, _ := json.Marshal(a)
+	return b
+}

services/imgedit/store.go

@@ -0,0 +1,66 @@
+package imgedit
+
+import (
+	"encoding/json"
+	"io"
+	"os"
+	"path/filepath"
+
+	"lmika.dev/lmika/weiro/models"
+)
+
+type sessionStore struct {
+	baseDir string
+}
+
+func (ss *sessionStore) create(newSession models.ImageEditSession) error {
+	sessionMeta, err := json.Marshal(newSession)
+	if err != nil {
+		return err
+	}
+
+	if err := os.MkdirAll(filepath.Join(ss.baseDir, newSession.GUID), 0755); err != nil {
+		return err
+	}
+	if err := os.WriteFile(filepath.Join(ss.baseDir, newSession.GUID, "session.json"), sessionMeta, 0644); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (ss *sessionStore) get(guid string) (models.ImageEditSession, error) {
+	sessionDataBts, err := os.ReadFile(filepath.Join(ss.baseDir, guid, "session.json"))
+	if err != nil {
+		return models.ImageEditSession{}, err
+	}
+
+	sessionData := models.ImageEditSession{}
+	if err := json.Unmarshal(sessionDataBts, &sessionData); err != nil {
+		return models.ImageEditSession{}, err
+	}
+
+	return sessionData, nil
+}
+
+func (ss *sessionStore) getImage(session models.ImageEditSession, imageFilename string) (string, func() (io.ReadCloser, error), error) {
+	fullPath := filepath.Join(ss.baseDir, session.GUID, imageFilename)
+	if s, err := os.Stat(fullPath); err != nil {
+		return "", nil, err
+	} else if s.IsDir() {
+		return "", nil, os.ErrNotExist
+	}
+
+	var mimeType string
+	switch filepath.Ext(imageFilename) {
+	case ".jpg", ".jpeg":
+		mimeType = "image/jpeg"
+	case ".png":
+		mimeType = "image/png"
+	default:
+		return "", nil, models.UnsupportedImageFormat
+	}
+
+	return mimeType, func() (io.ReadCloser, error) {
+		return os.Open(fullPath)
+	}, nil
+}