feat: end-to-end type safety with TypeScript + Elysia backend

.dockerignore

@@ -0,0 +1,5 @@
+__pycache__
+.git*
+.vscode
+backend
+node_modules

.github/workflows/backend-ci.yml

@@ -0,0 +1,34 @@
+name: Run Backend CI
+
+on:
+  pull_request:
+    paths:
+      - 'backend1/**'
+
+defaults:
+  run:
+    working-directory: backend1
+
+permissions:
+  contents: read
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Detect Bun version
+        id: detect-bun-version
+        run: echo "BUN_VERSION=$(jq -r '.engines.bun' package.json)" >> $GITHUB_OUTPUT
+
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: ${{ steps.detect-bun-version.outputs.BUN_VERSION }}
+
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+
+      - name: Run Biome
+        run: bun run ci

.github/workflows/backend-tests.yml

@@ -3,11 +3,11 @@ name: Run Backend Tests
 on:
   pull_request:
     paths:
-      - 'backend/**'
+      - 'backend1/**'
 
 defaults:
   run:
-    working-directory: backend
+    working-directory: backend1
 
 permissions:
   contents: read
@@ -19,17 +19,16 @@ jobs:
     steps:
       - uses: actions/checkout@v5
 
-      - name: Install poetry
-        run: pipx install poetry
+      - name: Detect Bun version
+        id: detect-bun-version
+        run: echo "BUN_VERSION=$(jq -r '.engines.bun' package.json)" >> $GITHUB_OUTPUT
 
-      - name: Set up Python 3.14
-        uses: actions/setup-python@v6
+      - uses: oven-sh/setup-bun@v2
         with:
-          python-version: '3.14'
-          cache: 'poetry'
+          bun-version: ${{ steps.detect-bun-version.outputs.BUN_VERSION }}
 
       - name: Install dependencies
-        run: poetry install --no-root --with dev
+        run: bun install --frozen-lockfile
 
       - name: Run tests
-        run: poetry run pytest
+        run: bun test

Dockerfile

@@ -0,0 +1,12 @@
+FROM oven/bun:1.3.1-alpine
+
+COPY backend1/package.json backend1/bun.lock ./backend1/
+COPY frontend/package.json frontend/bun.lock ./frontend/
+COPY packages/elysia/package.json ./packages/elysia/
+COPY package.json bun.lock ./
+
+RUN bun install --frozen-lockfile
+
+COPY . .
+
+CMD ["bun", "dev", "--host"]

README.md

@@ -5,7 +5,6 @@ This repository contains the code for a BPMN Real-Time Collaboration Challenge.
 ## Prerequisites
 
 - Docker
-- Docker Compose
 
 ## Running the application
 
@@ -15,12 +14,17 @@ This repository contains the code for a BPMN Real-Time Collaboration Challenge.
    cd summ-ai
    ```
 
-2. Build and run the application using Docker Compose:
+2. Build the application using Docker:
    ```bash
-   docker compose up --build
+   docker build -t summ-ai .
    ```
 
-3. Access the application:
+3. Run the application using Docker:
+   ```bash
+   docker run --rm -p 5173:5173 -p 8000:8000 summ-ai
+   ```
+
+4. Access the application:
    - Frontend: [http://localhost:5173](http://localhost:5173)
    - Backend API: [http://localhost:8000](http://localhost:8000)
 
@@ -38,7 +42,6 @@ This repository contains the code for a BPMN Real-Time Collaboration Challenge.
   - This restricts locking selected elements
 - The lock marker does not prohibit any user from editing the element
 - The storage of diagram data inside the frontend application is intended for prototyping purposes only
-- End-to-end type safety
 - Tests in the frontend application are not implemented
 
 ## Demo

backend1/README.md

@@ -0,0 +1,13 @@
+## Backend
+
+The backend is a Elysia application that handles the WebSocket connections and the API requests. The application communicates with the frontend using the same Elysia application with end-to-end type safety.
+
+### Prerequisites
+
+- Bun 1.3.1
+
+### Installation
+
+1. Navigate to the backend directory
+2. Install the dependencies: `bun install --frozen-lockfile`
+3. Run the application: `bun dev --host`

backend1/biome.json

@@ -0,0 +1,39 @@
+{
+  "$schema": "https://biomejs.dev/schemas/2.3.2/schema.json",
+  "vcs": {
+    "enabled": false,
+    "clientKind": "git",
+    "useIgnoreFile": false
+  },
+  "files": {
+    "includes": ["src/**/*.ts"],
+    "ignoreUnknown": false
+  },
+  "formatter": {
+    "enabled": true,
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineWidth": 120
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true
+    }
+  },
+  "javascript": {
+    "formatter": {
+      "quoteStyle": "single",
+      "trailingCommas": "all",
+      "semicolons": "asNeeded"
+    }
+  },
+  "assist": {
+    "enabled": true,
+    "actions": {
+      "source": {
+        "organizeImports": "on"
+      }
+    }
+  }
+}

backend1/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "backend1",
+  "version": "0.1.0",
+  "engines": {
+    "bun": "1.3.1"
+  },
+  "scripts": {
+    "dev": "bun --watch --no-clear-screen src/index.ts",
+    "start": "bun run src/index.ts",
+    "typecheck": "bun tsc --noEmit",
+    "check": "biome check .",
+    "check:fix": "biome check --write .",
+    "ci": "biome ci",
+    "lint": "biome lint .",
+    "lint:fix": "biome lint --write ."
+  },
+  "dependencies": {
+    "@elysiajs/cors": "1.4.0",
+    "@elysiajs/eden": "catalog:",
+    "elysia": "catalog:"
+  },
+  "devDependencies": {
+    "@biomejs/biome": "catalog:",
+    "@types/bun": "catalog:",
+    "typescript": "catalog:"
+  },
+  "module": "src/index.ts"
+}

backend1/src/diagram-manager.ts

@@ -0,0 +1,65 @@
+export class DiagramState {
+  private currentXml: string = `<?xml version="1.0" encoding="UTF-8"?>
+<bpmn:definitions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" id="Definitions_1tmf6t6" targetNamespace="http://bpmn.io/schema/bpmn" exporter="bpmn-js" exporterVersion="17.11.1">
+  <bpmn:process id="Process_1lclg3e" isExecutable="false">
+    <bpmn:startEvent id="StartEvent_1sgwknq" />
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1lclg3e">
+      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1sgwknq">
+        <dc:Bounds x="156" y="82" width="36" height="36" />
+      </bpmndi:BPMNShape>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>`
+  private lockedElements: Map<string, string> = new Map()
+
+  getXml(): string {
+    return this.currentXml
+  }
+
+  updateXml(xml: string): void {
+    this.currentXml = xml
+  }
+
+  requestLock(elementIds: string[], userId: string): boolean {
+    // Check if any of the requested elements are already locked by another user
+    for (const elementId of elementIds) {
+      const currentOwner = this.lockedElements.get(elementId)
+      if (currentOwner && currentOwner !== userId) {
+        return false
+      }
+    }
+
+    // Lock all requested elements
+    for (const elementId of elementIds) {
+      this.lockedElements.set(elementId, userId)
+    }
+
+    return true
+  }
+
+  releaseLock(elementIds: string[]): void {
+    for (const elementId of elementIds) {
+      this.lockedElements.delete(elementId)
+    }
+  }
+
+  hasLockedElements(): boolean {
+    return this.lockedElements.size > 0
+  }
+
+  getLockedElements(): Record<string, string> {
+    return Object.fromEntries(this.lockedElements)
+  }
+
+  releaseUserLocks(userId: string): void {
+    const elementsToRelease: string[] = []
+    for (const [elementId, owner] of this.lockedElements) {
+      if (owner === userId) {
+        elementsToRelease.push(elementId)
+      }
+    }
+    this.releaseLock(elementsToRelease)
+  }
+}

backend1/src/index.ts

@@ -0,0 +1,9 @@
+import { app as websocketApp } from '@backend/websocket'
+import { cors } from '@elysiajs/cors'
+import { Elysia } from 'elysia'
+
+const app = new Elysia().use(cors()).use(websocketApp).listen(8000)
+
+console.log(`Server running on port ${app.server?.port}`)
+
+export type App = typeof app