assets/js/controllers/edit_upload.js

@@ -36,10 +36,15 @@ const processors = [
 ];
 
 export default class UploadEditController extends Controller {
-    static targets = ['processList'];
+    static targets = ['processList', 'preview'];
+    static values = {
+        uploadId: Number,
+        siteId: Number,
+    };
 
     connect() {
         this._rebuildProcessList();
+        this._createSession();
     }
 
     _rebuildProcessList() {
@@ -56,4 +61,22 @@ export default class UploadEditController extends Controller {
         el.innerHTML = cardOuter;
         // END TEMP
     }
+
+    async _createSession() {
+        try {
+            let resp = await fetch(`/sites/${this.siteIdValue}/imageedit/`, {
+                method: 'POST',
+                body: JSON.stringify({
+                    "base_upload": this.uploadIdValue,
+                })
+            });
+
+            this._state = await resp.json();
+            this.previewTarget.src = this._state.preview_url;
+
+            console.log("Session created");
+        } catch (e) {
+            console.error(e);
+        }
+    }
 }

cmds/server.go

@@ -111,6 +111,7 @@ Starting weiro without any arguments will start the server.
 			lh := handlers.LoginHandler{Config: cfg, AuthService: svcs.Auth}
 			ph := handlers.PostsHandler{PostService: svcs.Posts, CategoryService: svcs.Categories}
 			uh := handlers.UploadsHandler{UploadsService: svcs.Uploads}
+			ieh := handlers.ImageEditHandlers{ImageEditService: svcs.ImageEdit}
 			ssh := handlers.SiteSettingsHandler{SiteService: svcs.Sites}
 			ch := handlers.CategoriesHandler{CategoryService: svcs.Categories}
 			pgh := handlers.PagesHandler{PageService: svcs.Pages}
@@ -151,6 +152,9 @@ Starting weiro without any arguments will start the server.
 			siteGroup.Delete("/uploads/:uploadID", uh.Delete)
 			siteGroup.Get("/uploads/:uploadID/edit", uh.Edit)
 
+			siteGroup.Post("/imageedit", ieh.Create)
+			siteGroup.Get("/imageedit/:sessionID/preview/:versionID", ieh.Preview)
+
 			siteGroup.Get("/settings", ssh.General)
 			siteGroup.Post("/settings", ssh.UpdateGeneral)
 

handlers/imageedit.go

@@ -0,0 +1,67 @@
+package handlers
+
+import (
+	"bufio"
+	"io"
+	"log"
+	"net/http"
+
+	"github.com/gofiber/fiber/v3"
+	"lmika.dev/lmika/weiro/models"
+	"lmika.dev/lmika/weiro/services/imgedit"
+)
+
+type ImageEditHandlers struct {
+	ImageEditService *imgedit.Service
+}
+
+func (ieh ImageEditHandlers) Create(c fiber.Ctx) error {
+	var req struct {
+		BaseUploadID int64 `json:"base_upload"`
+	}
+
+	if err := c.Bind().JSON(&req); err != nil {
+		return err
+	}
+
+	res, err := ieh.ImageEditService.NewSession(c.Context(), req.BaseUploadID)
+	if err != nil {
+		return err
+	}
+
+	var resp = struct {
+		Session    models.ImageEditSession `json:"session"`
+		PreviewURL string                  `json:"preview_url"`
+	}{
+		Session:    res,
+		PreviewURL: res.PreviewURL(),
+	}
+
+	return c.Status(http.StatusCreated).JSON(resp)
+}
+
+func (ieh ImageEditHandlers) Preview(c fiber.Ctx) error {
+	log.Printf("Previewing image edit session %v/%v", c.Params("sessionID"), c.Params("versionID"))
+	sessionID := c.Params("sessionID")
+	versionID := c.Params("versionID")
+
+	mimeTime, rw, err := ieh.ImageEditService.LoadImageVersion(c.Context(), sessionID, versionID)
+	if err != nil {
+		return err
+	}
+
+	c.Set("Content-Type", mimeTime)
+	c.Status(http.StatusOK)
+	return c.SendStreamWriter(func(w *bufio.Writer) {
+		rw, err := rw()
+		if err != nil {
+			return
+		}
+		defer rw.Close()
+
+		_, err = io.Copy(w, rw)
+		if err != nil {
+			return
+		}
+	})
+}

models/errors.go

@@ -8,3 +8,4 @@ var NotFoundError = errors.New("not found")
 var SiteRequiredError = errors.New("site required")
 var DeleteDebounceError = errors.New("permanent delete too soon, try again in a few seconds")
 var SlugConflictError = errors.New("a record with this slug already exists")
+var UnsupportedImageFormat = errors.New("unsupported image format")

models/imgedit.go

@@ -0,0 +1,59 @@
+package models
+
+import (
+	"crypto/md5"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+)
+
+type ImageEditSession struct {
+	GUID         string               `json:"guid"`
+	SiteID       int64                `json:"siteId"`
+	UserID       int64                `json:"userId"`
+	BaseUploadID int64                `json:"baseUploadId"`
+	ImageExt     string               `json:"imageExt"`
+	CreatedAt    time.Time            `json:"createdAt"`
+	UpdatedAt    time.Time            `json:"updatedAt"`
+	Processors   []ImageEditProcessor `json:"processors"`
+}
+
+func (ieh ImageEditSession) PreviewURL() string {
+	return fmt.Sprintf("/sites/%v/imageedit/%v/preview/%v", ieh.SiteID, ieh.GUID, ieh.Processors[len(ieh.Processors)-1].VersionID)
+}
+
+func (ieh *ImageEditSession) RecalcVersionIDs() {
+	for i, p := range ieh.Processors {
+		if i == 0 {
+			p.SetVersionID("")
+		} else {
+			p.SetVersionID(ieh.Processors[i-1].VersionID)
+		}
+
+		ieh.Processors[i] = p
+	}
+}
+
+type ImageEditProcessor struct {
+	Type  string          `json:"type"`
+	Props json.RawMessage `json:"props"`
+
+	// VersionID is a unique hash of the particular processor. This includes the version ID of the previous processor,
+	// thereby causing a change of one processor to affect the version IDs of processors down the line.
+	VersionID string `json:"versionId"`
+}
+
+func (ieh *ImageEditProcessor) SetVersionID(previousVersionID string) {
+	var sb strings.Builder
+	sb.WriteString(previousVersionID)
+	sb.WriteString("-")
+	sb.WriteString(ieh.Type)
+	sb.WriteString("-")
+	sb.WriteString(string(ieh.Props))
+	ieh.VersionID = fmt.Sprintf("%x", md5.Sum([]byte(sb.String())))
+}
+
+type CopyUploadProps struct {
+	UploadID int64 `json:"uploadId"`
+}

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
+}

services/services.go

@@ -8,6 +8,7 @@ import (
 	"lmika.dev/lmika/weiro/providers/uploadfiles"
 	"lmika.dev/lmika/weiro/services/auth"
 	"lmika.dev/lmika/weiro/services/categories"
+	"lmika.dev/lmika/weiro/services/imgedit"
 	"lmika.dev/lmika/weiro/services/pages"
 	"lmika.dev/lmika/weiro/services/posts"
 	"lmika.dev/lmika/weiro/services/publisher"
@@ -23,6 +24,7 @@ type Services struct {
 	Posts          *posts.Service
 	Sites          *sites.Service
 	Uploads        *uploads.Service
+	ImageEdit      *imgedit.Service
 	Categories     *categories.Service
 	Pages          *pages.Service
 }
@@ -41,6 +43,7 @@ func New(cfg config.Config) (*Services, error) {
 	postService := posts.New(dbp, publisherQueue)
 	siteService := sites.New(dbp)
 	uploadService := uploads.New(dbp, ufp, filepath.Join(cfg.ScratchDir, "uploads", "pending"))
+	imageEditService := imgedit.New(uploadService, filepath.Join(cfg.ScratchDir, "imageedit"))
 	categoriesService := categories.New(dbp, publisherQueue)
 	pagesService := pages.New(dbp, publisherQueue)
 
@@ -52,6 +55,7 @@ func New(cfg config.Config) (*Services, error) {
 		Posts:          postService,
 		Sites:          siteService,
 		Uploads:        uploadService,
+		ImageEdit:      imageEditService,
 		Categories:     categoriesService,
 		Pages:          pagesService,
 	}, nil

views/uploads/edit.html

@@ -1,8 +1,12 @@
 <main class="flex-grow-1 flex-shrink-1">
   <div class="flex-grow-1 flex-shrink-1 d-flex flex-column">
-    <div class="row flex-grow-1 flex-shrink-1 m-0" data-controller="edit-upload">
+    <div class="row flex-grow-1 flex-shrink-1 m-0"
+         data-controller="edit-upload"
+         data-edit-upload-site-id-value="{{ .site.ID }}"
+         data-edit-upload-upload-id-value="{{ .upload.Upload.ID }}"
+    >
       <figure class="col-md-9 p-3">
-        <img src="{{ .upload.URL }}" alt="{{ .upload.Upload.Alt }}" class="img-fluid">
+        <img data-edit-upload-target="preview" src="{{ .upload.URL }}" alt="{{ .upload.Upload.Alt }}" class="img-fluid">
       </figure>
       <div class="col-md-3 p-3">
         <div data-edit-upload-target="processList"></div>