diff-patch-sync-demo

This repo contains a client-server-example with Angular 8 frontend and NestJS REST-backend based on Node.js server integrating the diff-patch-sync-library on both sides.

Frameworks

• Provide Client-Server-Synchronisation using diff-patch-sync. This is a TypeScript library for syncing collaborative web-applications implementing the Differential Synchronization Algorithm developed by Neil Fraser with REST-backends via HTTP.
• Uses Angular 8 Framework to develop frontend functionality and to serve a single-page-application.
• Provide client-side storage by using IndexedDB.
• In order to make the client fully offline-capable to provide static files using Angular specific Service Worker API (@angular/service-worker).
• Makes use of NestJS, a framework for building efficient, scalable REST-backends based on Node.js.
• On server-side the object-relational-mapper TypeOrm is used for better entity management, migrations and automatic migrations generation.
• An lightweight open-source SQL-database PostgreSQL is used for persisting data server-side.

Demo

See a running demo of a collaborative todo-app here: Demo Todo App

Hint: It is recommended to use two different browsers (e.g. Chrome and Firefox) or two instances of Chrome (one instance in private mode ("Ctrl + Shift + n")) because IndexedDB is used and the instances should not share their databases.

Prerequisites for local development

• Make sure to have node version v10.9.0 installed (Node.js download link)
• Install Dependencies executing cd client/ && npm install && cd ../server/ && npm install
• Install http-server globally when you want to serve the application via CLI-Http-Server with npm install -g http-server
• Make sure to have Docker installed (Docker download link)
• Bring up the PostgreSLQ database by running cd docker && docker-compose up
• Run database migrations using TypeOrm migrations with cd server/ && npm run migrate:run

Client

Start Angular Development server

Run npm run start for a dev server. Navigate to http://localhost:4200/. The app will automatically reload if you change any of the source files.

Serve via CLI-Http-Server

Run npm run start:offline for running the app with Server Worker activated. Navigate to http://localhost:4200/.

Build

Run npm run build to build the project. The build artifacts will be stored in the dist/ directory. Use the npm run build:prod for a production build.

Running end-to-end tests

Run npm run e2e to execute the end-to-end tests locally via Protractor. Use npm run e2e:noDevServer to execute tests when you've started the dev server manually before.

Server

Start Node.js Server

Run npm run start to start Nest application dev server. The app will automatically reload if you change any of the source files. Use the npm run start:prod to start in production environments.

Build

Run npm run build to build the project. The build artifacts will be stored in the dist/ directory.

Continuous Integration

The application is continuously tested and deployed within a CI-environment. Gitlab CI is used for that purpose. Four stages are passed, which are defined in the .gitlab-ci.yml file.

• build -> create production build artifacts for client and server
• test -> run end-to-end test with a temporary created database running in docker environment
• migrate -> only if the test passes, run migrations on the production database
• deploy -> only if the test passes, deploy application to target http://todo-app.w11k.de/

References

• diff-patch-sync - TypeScript library for syncing collaborative web-applications with REST-backends in order to make them offline-capable.
• lodash - A modern JavaScript utility library delivering modularity, performance, & extras.
• uuid - Generate RFC-compliant UUIDs in JavaScript.
• ngx-indexed-db - A service that wraps IndexedDB database in an Angular service. It exposes very simple promises API to enable the usage of IndexedDB without most of it plumbing.
• typeorm - ORM for TypeScript and JavaScript (ES7, ES6, ES5). Supports MySQL, PostgreSQL, MariaDB, SQLite, MS SQL Server, Oracle, SAP Hana, WebSQL databases. Works in NodeJS, Browser, Ionic, Cordova and Electron platforms
• postgresql - PostgreSQL Database Management System
• Angular CLI - One frontend framework. Mobile & desktop
• NestJS CLI - A progressive Node.js framework for building efficient, scalable, and enterprise-grade server-side applications on top of TypeScript & JavaScript (ES6, ES7, ES8)

Authors

• Mario Sallat - Github