Initial commit

.dockerignore

@@ -0,0 +1,9 @@
+# Ignore all files by default.
+*
+
+# White list only the required files and folders.
+!src/
+!.prettierignore
+!.prettierrc
+!package.json
+!yarn.lock

.env

@@ -0,0 +1,4 @@
+# In normal circumstances this file should not be under source control, however, it's fine for this demonstration repository.
+
+APP_PORT=54321
+MONGODB_URL=mongodb://appUser:examplePassword@database:27017/urlShortener

.gitignore

@@ -0,0 +1,5 @@
+database/data/
+node_modules/
+yarn-debug.log*
+yarn-error.log*
+.DS_Store

.nvmrc

@@ -0,0 +1 @@
+20

.prettierignore

@@ -0,0 +1 @@
+**/database/data/

.prettierrc

@@ -0,0 +1,3 @@
+{
+  "singleQuote": true
+}

.vscode/extensions.json

@@ -0,0 +1,3 @@
+{
+  "recommendations": ["esbenp.prettier-vscode"]
+}

.vscode/settings.json

@@ -0,0 +1,6 @@
+{
+  "[javascript][typescript]": {
+    "editor.defaultFormatter": "esbenp.prettier-vscode",
+    "editor.formatOnSave": true
+  }
+}

Dockerfile

@@ -0,0 +1,15 @@
+FROM node:20-alpine AS base
+
+LABEL maintainer="Anthony Hastings <[email protected]>"
+
+USER node
+
+WORKDIR /url-shortener
+
+COPY --chown=node ./package.json ./yarn.lock ./
+
+RUN yarn install --frozen-lockfile && yarn cache clean
+
+COPY --chown=node . ./
+
+CMD yarn start

compose.yml

@@ -0,0 +1,45 @@
+version: "3.8"
+services:
+  database:
+    image: mongo:7
+    ports:
+      - 45678:27017
+    environment:
+      MONGO_INITDB_ROOT_USERNAME: root
+      MONGO_INITDB_ROOT_PASSWORD: 123456
+    volumes:
+      - ./database/data:/data/db
+      - ./database/init:/docker-entrypoint-initdb.d
+    healthcheck:
+      test: echo 'db.runCommand("ping").ok' | mongosh database:27017 --quiet
+      start_period: 10s
+      interval: 3s
+      timeout: 10s
+      retries: 3
+  app:
+    build:
+      context: ./
+      target: base
+    command: sh -c "yarn run dev"
+    environment:
+      APP_PORT: ${APP_PORT}
+      MONGODB_URL: ${MONGODB_URL}
+    ports:
+      - ${APP_PORT}:${APP_PORT}
+    healthcheck:
+      test: wget -qO- http://app:$APP_PORT/health || exit 1
+      start_period: 5s
+      interval: 5s
+      timeout: 3s
+      retries: 3
+    depends_on:
+      database:
+        condition: service_healthy
+        restart: true
+    x-develop:
+      watch:
+        - action: sync
+          path: ./src
+          target: /url-shortener/src
+        - action: rebuild
+          path: package.json

database/init/01-schema.js

@@ -0,0 +1,20 @@
+db = new Mongo().getDB('urlShortener');
+
+db.createCollection('links', { capped: false });
+
+db.links.createIndex({ shortId: 1 });
+
+db.links.insert([
+  {
+    shortId: 'fPbD2NkcxZ70QPT',
+    target: 'https://www.google.co.uk/',
+  },
+  {
+    shortId: '4Biym9VuXikRrr4',
+    target: 'https://www.reddit.com/',
+  },
+  {
+    shortId: 'Zx8lP5bWMhEgnvH',
+    target: 'https://www.youtube.com/',
+  },
+]);

database/init/02-user.js

@@ -0,0 +1,13 @@
+db = new Mongo().getDB('urlShortener');
+
+db.createUser({
+  user: 'appUser',
+  pwd: 'examplePassword',
+  roles: [
+    {
+      role: 'readWrite',
+      db: 'urlShortener',
+      collection: 'links',
+    },
+  ],
+});

package.json

@@ -0,0 +1,27 @@
+{
+  "name": "url-shortener",
+  "version": "1.0.0",
+  "description": "An example of a URL shortening service",
+  "author": "Anthony Hastings <[email protected]> (https://antwan1986.github.io/)",
+  "license": "MIT",
+  "private": true,
+  "main": "src/index.mjs",
+  "module": "src/index.mjs",
+  "type": "module",
+  "scripts": {
+    "dev": "nodemon src/index.mjs",
+    "dev:native": "node --watch src/index.mjs",
+    "start": "node src/index.mjs"
+  },
+  "dependencies": {
+    "dotenv": "^16.3.1",
+    "express": "^4.18.2",
+    "mongoose": "^7.6.2",
+    "nanoid": "^5.0.2",
+    "zod": "^3.22.4"
+  },
+  "devDependencies": {
+    "nodemon": "^3.0.1",
+    "prettier": "^3.0.3"
+  }
+}

src/config.mjs

@@ -0,0 +1,24 @@
+import { z } from 'zod';
+
+export const configSchema = z.object({
+  APP_PORT: z.string(),
+  MONGODB_URL: z.string(),
+});
+
+export let config;
+
+try {
+  config = configSchema.parse(process.env);
+} catch (err) {
+  if (err instanceof z.ZodError) {
+    const { fieldErrors } = err.flatten();
+
+    const errorMessage = Object.entries(fieldErrors)
+      .map(([field, errors]) =>
+        errors ? `${field}: ${errors.join(', ')}` : field,
+      )
+      .join('\n  ');
+
+    throw new Error(`Missing environment variables:\n  ${errorMessage}`);
+  }
+}

src/index.mjs

@@ -0,0 +1,68 @@
+import 'dotenv/config';
+import express from 'express';
+import mongoose from 'mongoose';
+import { nanoid } from 'nanoid';
+import { config } from './config.mjs';
+import { LinkModel } from './models/link.mjs';
+import { isValidHTTPURL } from './utils.mjs';
+
+mongoose.connection.once('open', () => {
+  console.log('Connected to MongoDB');
+});
+
+await mongoose.connect(config.MONGODB_URL);
+
+const app = express();
+
+app.use(express.json());
+
+app.get('/health', (_req, res) => {
+  res.status(200).json({ status: 'ok' });
+});
+
+app.get('/links/:shortId', async (req, res) => {
+  const link = await LinkModel.findOne({ shortId: req.params.shortId });
+
+  if (link === null) {
+    return res.status(404).json({ success: false, error: 'Record not found' });
+  }
+
+  res.status(200).json({ success: true, data: link.toJSON() });
+});
+
+app.post('/links', async (req, res) => {
+  const isValidTarget = isValidHTTPURL(req.body.target);
+  if (!isValidTarget) {
+    return res.status(409).json({ success: false, error: 'Invalid target' });
+  }
+
+  const shortId = nanoid(25);
+
+  const existingLink = await LinkModel.findOne({ shortId });
+  if (existingLink) {
+    return res
+      .status(409)
+      .json({ success: false, error: 'Short Id already exists' });
+  }
+
+  const link = await new LinkModel({
+    shortId,
+    target: req.body.target,
+  }).save();
+
+  res.status(201).json({ success: true, data: link.toJSON() });
+});
+
+app.get('/:shortId', async (req, res) => {
+  const link = await LinkModel.findOne({ shortId: req.params.shortId });
+
+  if (link === null) {
+    return res.status(404).json({ success: false, error: 'Record not found' });
+  }
+
+  res.redirect(301, link.target);
+});
+
+app.listen(config.APP_PORT, '0.0.0.0', () => {
+  console.info(`Listening on port 0.0.0.0:${config.APP_PORT}`);
+});

src/models/link.mjs

@@ -0,0 +1,9 @@
+import mongoose from 'mongoose';
+
+export const LinkModel = mongoose.model(
+  'Link',
+  new mongoose.Schema({
+    shortId: String,
+    target: String,
+  }),
+);

src/utils.mjs

@@ -0,0 +1,6 @@
+export const isValidHTTPURL = (str) => {
+  const urlPattern =
+    /^https?:\/\/[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]$/;
+
+  return urlPattern.test(str);
+};