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Tech Stack

This document describes the general technology stack, and in particular the technologies used for the Application layer, which do not change between modes.

Application layer

React Frontend Web App

Custom Response Items

ASP.NET Core Backend API

Data layer
NoSQL Database(s)
Image store

Application layer​

Frontend​

The Frontend application is a Client Side React Single Page Application.

  • It's pure JavaScript
    • It is however modern ECMAScript, so is transpiled using Babel.
  • It uses a very popular component driven framework: React
    • This should be beneficial for developer accessibility
    • It really helped enable the ability to dynamically load custom response items
  • It's served by the Backend application process.

Custom Response Items​

Custom Response Items are written as React Components, with some additional metadata.

Refer to the component-boilerplate wiki for detailed information on the structure of Response Components and how to write them.

  • They're React, the same as the Frontend app.
    • They use Emotion so they can be bundled into a single JavaScript file, but still be styled.
  • They're modern ECMAScript, using the ES Modules standard
  • They're discovered and served by the Backend app at runtime
    • You can drop new components into the components/ folder locally, and only a page refresh is required to load them.
  • They're loaded by the frontend as ES Modules at runtime.
  • Using a NoSQL datastore allows us to store response data with flexible schema defined by the Response Items, not the Platform.
  • React allows Components to use PropTypes to define Parameter and Response schema that the Platform can validate or interact with (e.g. providing a rich editor UI).

Backend​

The Backend application is an ASP.NET Core MVC REST API.

  • It's .NET so it's cross-platform for Linux, macOS and Windows.
  • It's self-hosting - it doesn't require a reverse proxy in front of it.
  • It's capable of hosting different content at different routes
    • in the case of the Survey Platform:
      • there are some custom routes which bypass the MVC framework (e.g. /version)
      • there are routes to the Client Side application
      • there are routes to MVC controllers (e.g. /api/...)

The above points allow keeping with the single-process design for Workshop mode while being flexible enough to support running an online service in Hosted mode.

Users can just run the backend and everything comes up, or they run an online service in a typical hosting setup.

  • The backend can be published as a platform binary which can run anywhere the platform (.NET) runtime is available.
  • It can also be published as a native executable binary for supported platforms (e.g. decsys.exe for Windows).

Data layer​

The architectural approach and data layer technology differs somewhat between operating modes, and this is explained in their own documents:

However any text datastores (i.e. not for files such as Images) are always a form of NoSQL (or Document based) Database.