Data Sync for Apps: With Offline Support, but Without Cloud

This repository contains a showcase for synchronizing on-premises data including offline support, powered by PouchDB, Ionic 2 and Thinktecture RelayServer.

Repository Structure

• server – working directory of the PouchDB Server, its files will be placed here
• connector – placeholder directory where build artifacts of Thinktecture RelayServer On-Premises Connector Service should be placed
• client – source files of the Ionic 2 client app live here

Prerequisites

• Not surprisingly, you need Node.js and Node Package Manager installed
• Running instance of Thinktecture RelayServer
  • Requires RabbitMQ and Microsoft SQL Server
• Build of Thinktecture RelayServer On-Premises Connector Service
  • .NET application
  • Integrating RelayServer into applications is an architectural decision. Therefore, the Connector Service is not a part of the pre-built RelayServer release and it has to be built/integrated manually.
  • Clone this repository and build the Thinktecture.RelayServer solution
  • Copy the build output of Thinktecture.RelayServer.OnPremisesConnector over to the target machine (preferably the connector directory of this repository)
• If you want to build/execute the client, Ionic 2 (Beta) needs to be installed globally by running npm i -g ionic@beta

Setup

• Please run npm i first.
• Relay Server
  • Public facing
  • Can be hosted anywhere (inhouse, hoster, …)
  • Refer to the RelayServer documentation (German) for installing and running RelayServer
• Local On-Premises Device
  • Connects to Relay Server using the Thinktecture RelayServer Connector Service (.NET or Mono runtime required)
  • Only outgoing connections to port 443 (HTTPS) must be allowed
  • Not public facing
  • Contains private data, here provided by PouchDB Server (On-Premises Application)
  • Run the connector by launching its executable (.NET or Mono runtime required), e.g. by calling npm run connector (.NET) or npm run connector-mono (Mono) respectively
  • Run PouchDB Sever by launching its executable, e.g. by calling npm run pouchdb-server
• Mobile Device (or any other remote client)
  • Connects to Relay Server which is connected to the on-premises data storage
  • Support for editing data offline and synchronizing it with the remote database
  • Please set the remote property of the Data service in client/app/providers/data/data.js to the remote database endpoint (e.g. https://example.com/relay/raspberry-pi/pouchdb/pizzas/)
  • Run the client by navigating to the client directory and execute ionic serve
  • To run the client on a mobile device, add the target platforms using ionic platform add <platform> (ios, android or windows) and run ionic run <platform> --device

Dependencies

• PouchDB Server, CouchDB-compatible HTTP server using PouchDB and Node.js
• Thinktecture RelayServer, enabling bidirectional, secure communication between on-premises applications and mobile clients
• Ionic 2, advanced HTML5 mobile development framework and SDK
  • Angular 2, development platform for building mobile and desktop web applications
  • PouchDB, a pocket-sized database

Live and in Color

This sample is/was presented at the following conferences/meetups.

• RheinNeckarJS, April 27, 2016, 20:00, Mafinex, Mannheim.
• DeveloperWeek 2016, June 20, 2016, 14:15, Nuremberg Conference Center, Nuremberg.

Further Reading

• Weyer, Christian: Offline-First Architectures for HTML5 Apps (German)
• Morony, Josh: Syncing Data with PouchDB and Cloudant in Ionic 2
• Thinktecture RelayServer Documentation (German)
• PouchDB Documentation
• Ionic 2 Documentation

Known Issues

• Installing pouchdb-server using a current version of Node.js will fail on Debian 7 (Wheezy). Either use an older version of Node.js (e.g. 0.10) or update your version of GCC.
• Live/continuous replication is unsupported as RelayServer doesn’t support Long Polling.