Systems Development and Frameworks - 2020/21

This is our homework solutions repository for the course Systems Development and Frameworks at Hochschule für Technik und Wirtschaft in Berlin.

In ./exercises you'll find the exercises, in ./webapp you'll find a single webapp incorporating the solutions.

Setup and run the webapp

All commands assume you're located in the webapp directory.

Project setup

$ (webapp) npm install

Run unit tests

$ (webapp) npm run test:unit

Compiles and hot-reloads for development

$ (webapp) npm run serve

Compiles and minifies for production

$ (webapp) npm run build

Run linter

$ (webapp) npm run lint

Setup and run the backend

All commands assume you're located in the backend directory.

The backend utilizes JSON Web Tokens for authentication. To cryptographically sign the tokens the backend application requires an ECDSA key to be present. Such a key can be generated with OpenSSL as follows:

$ (backend) openssl ecparam -genkey -name prime256v1 -noout -out private.pem

The path to the private key to be used is assumed to be a file named private.pem in the current working directory. You can specify another location by setting the JWT_PRIVATE_KEY_LOCATION environment variable (or setting it in a .env file).

A running neo4j database is also needed to test and run the backend; the database is used to store users, posts and their relations. At the moment only basic authentication is supported. You must at least provide a username and password combination through either environment variables NEO4J_USERNAME and NEO4J_PASSWORD, or in a .env file in scope. Other available settings (with their corresponding default values) are:

NEO4J_PROTOCOL = neo4j
NEO4J_HOST = localhost
NEO4J_PORT = 7687
NEO4J_DATABASE = neo4j
NEO4J_ENCRYPTED = ENCRYPTION_OFF
JWT_PRIVATE_KEY_LOCATION = private.pem

For testing and development purposes, running a neo4j Docker container is sufficient:

$ export NEO4J_USERNAME=neo4j NEO4J_PASSWORD=test
$ docker run -p 7474:7474 -p 7687:7687 --env=NEO4J_AUTH=NEO4J_USERNAME/$NEO4J_PASSWORD neo4j:4.2.1

Reasoning about choice of storage backend

The backend utilizes Neode (a neo4js OGM) for mutations and neo4j-graphql-js for queries. It directly interfaces with GraphQL, instead of e.g. an external GraphQL service, to store data mainly to for ease and speed of development and usage. Furthermore, this allows the application to be more flexible in terms of (graph) database design. Also, the test setup is simpler and instead of mocking another backend layer, an actual neo4j (test) database can be used.

Project setup

$ (backend) npm install

Compiles and hot-reloads for development

$ (backend) npm run dev

Run tests

$ (backend) npm run test

Run linter

$ (backend) npm run lint

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This ^ is you looking at our code? Have improvements? Raise issues and PRs!

Further questions? Reach out to us by texting either [email protected] or [email protected]