LearnSpace: full-stack educational whiteboard platform

Node.js/Express backend + vanilla JS frontend.
Features: real-time collaborative whiteboard (SSE), multi-page support,
LaTeX formulas, shapes/connectors, coordinate systems, number lines,
compass, zoom/pan, Catmull-Rom pencil smoothing, ruler/protractor with
rotation & resize controls, minimap navigation overlay, auto-measurements,
multi-page thumbnails sidebar, PNG export, page templates.
Student/teacher workflows: classes, assignments, library, dashboard.
Mobile responsive. SQLite (better-sqlite3).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/routes/classroom.js

@@ -0,0 +1,104 @@
+const router  = require('express').Router();
+const multer  = require('multer');
+const path    = require('path');
+const crypto  = require('crypto');
+const { authMiddleware, requireRole } = require('../middleware/auth');
+const rateLimit = require('../middleware/rateLimit');
+const c = require('../controllers/classroomController');
+
+/* ── multer for chat image attachments ─────────────────────────────────── */
+const _chatUploadsDir = path.join(__dirname, '../../uploads/chat');
+const _chatStorage = multer.diskStorage({
+  destination: (req, file, cb) => cb(null, _chatUploadsDir),
+  filename:    (req, file, cb) => {
+    const ext = path.extname(file.originalname).toLowerCase().replace(/[^.a-z0-9]/g, '');
+    cb(null, crypto.randomBytes(14).toString('hex') + ext);
+  },
+});
+const chatUpload = multer({
+  storage: _chatStorage,
+  limits:  { fileSize: 5 * 1024 * 1024 },
+  fileFilter: (req, file, cb) => {
+    const ok = ['image/jpeg','image/png','image/gif','image/webp'].includes(file.mimetype);
+    cb(null, ok);
+  },
+});
+
+const teacher = [authMiddleware, requireRole('teacher', 'admin')];
+const auth    = [authMiddleware];
+
+const chatLimiter = rateLimit({ windowMs: 5_000, max: 5, message: 'Слишком много сообщений, подождите' });
+
+// Template library — MUST be before /:id to avoid shadowing
+router.get('/templates',                  ...teacher, c.getTemplates);
+router.delete('/templates/:tid',          ...teacher, c.deleteTemplate);
+
+// Session lifecycle
+router.post('/',                          ...teacher, c.createSession);
+router.get('/online-students',            ...teacher, c.getOnlineStudents);
+router.get('/my/session',                 ...auth,    c.getMySession);
+router.get('/class/:classId/active',      ...auth,    c.getActiveSession);
+router.get('/my/active',                  ...auth,    c.getMyActive);
+router.get('/:id',                        ...auth,    c.getSession);
+router.delete('/:id',                     ...teacher, c.endSession);
+
+// Attendance
+router.post('/:id/join',                  ...auth,    c.joinSession);
+router.post('/:id/leave',                 ...auth,    c.leaveSession);
+router.get('/:id/participants',           ...auth,    c.getParticipants);
+router.get('/:id/attendance',             ...teacher, c.getAttendance);
+
+// Chat
+router.post('/:id/chat',                  ...auth, chatLimiter, c.sendChat);
+router.get('/:id/chat',                   ...auth,    c.getChat);
+router.post('/:id/chat/upload',           ...auth,    chatUpload.single('file'), c.uploadChatAttachment);
+router.post('/:id/chat/:msgId/react',     ...auth,    c.reactToMessage);
+
+// WebRTC signaling
+router.post('/:id/signal',                ...auth,    c.signal);
+
+// Whiteboard strokes
+router.post('/:id/strokes',               ...auth,    c.postStrokes);
+router.get('/:id/strokes',                ...auth,    c.getStrokes);
+router.delete('/:id/strokes/:strokeId',   ...teacher, c.deleteStroke);
+router.patch('/:id/strokes/:strokeId',    ...auth,    c.updateStroke);
+router.post('/:id/stroke-preview',        ...auth,    c.previewStroke);
+
+// Multi-page
+router.post('/:id/pages',                 ...teacher, c.addPage);
+router.put('/:id/page',                   ...teacher, c.changePage);
+router.patch('/:id/page-template',        ...teacher, c.updatePageTemplate);
+
+// Hand raise
+router.post('/:id/hand',                  ...auth,    c.raiseHand);
+router.delete('/:id/hand',                ...auth,    c.lowerHand);
+router.get('/:id/hands',                  ...auth,    c.getHands);
+
+// Whiteboard: clear page
+router.post('/:id/clear-page',            ...teacher, c.clearPage);
+
+// WebRTC: mute peer, screen share broadcast
+router.post('/:id/mute',                  ...teacher, c.mutePeer);
+router.post('/:id/screen',                ...teacher, c.screenStart);
+router.delete('/:id/screen',              ...teacher, c.screenStop);
+
+// Cursor broadcast (all participants)
+router.post('/:id/cursor',                ...auth,    c.broadcastCursor);
+
+// Message pin (teacher only)
+router.post('/:id/chat/:msgId/pin',       ...teacher, c.pinMessage);
+
+// Collaborative drawing permissions
+router.post('/:id/allow-draw/:userId',    ...teacher, c.allowDraw);
+router.delete('/:id/allow-draw/:userId',  ...teacher, c.revokeDraw);
+
+// Session notes (per user)
+router.get('/:id/notes',                  ...auth,    c.getNotes);
+router.put('/:id/notes',                  ...auth,    c.saveNotes);
+
+// Save current session as template
+router.post('/:id/save-template',         ...teacher, c.saveTemplate);
+// Load template into current session
+router.post('/:id/load-template',         ...teacher, c.loadTemplate);
+
+module.exports = router;