TAS Server 🚚

This repository contains the GraphQL API server originally built for the BCTC Truck Appointment System (TAS).

The TAS end-product is intended to have both web and native mobile interfaces. The backend web server exists in a separate environment (potentially physically) and exposes a GraphQL API endpoint for use by the web and mobile applications.

The tas-server connects to a MariaDB (or MySQL) database specified in the .env configuration.

Getting Started

Prerequisites

You must have the following installed:

• Node.js (^10.7.0)
• Yarn (^1.7.0)

Environment Variables

A .env environment variables file must also be added to the project root directory. It must contain the following definitions:

• PORT: port to open for TAS API server
• WEB_APP_URL: full URL of TAS web app
• SECRET_KEY: key used to sign API access tokens
• DB_CONNECTION_STRING: URL connection string for the MariaDB database (e.g. mysql://[email protected]/tas)
• TIMEZONE: IANA time zone string (e.g. Asia/Beirut) to set time zone (location of container server)
• MG_FROM_EMAIL: Mailgun sender email address (email sending)
• MG_API_KEY: Mailgun API key (email sending)
• MG_DOMAIN: Mailgun domain (email sending)
• TWILIO_ACCT_SID: Twilio Account Sid (SMS Sending)
• TWILIO_AUTH_TOKEN: Twilio Auth Token (SMS Sending)
• TWILIO_SRC_NUM: Twilio sender mobile number (SMS sending)
• DB_SETUP_DEFAULT_ALLOWED_APPTS_PER_HOUR: Initial config table value for defaultAllowedApptsPerHour
• DB_SETUP_MAX_TFU_PER_APPT: Initial config table value for maxTFUPerAppt
• DB_SETUP_ARRIVAL_WINDOW_LENGTH: Initial config table value for arrivalWindowLength must be 5, 10, 15, 30, or 60
• DB_SETUP_APPTS_QUERY_MAX_COUNT: Initial config table value for apptsQueryMaxCount
• ROOT_USER_PW: Password for the initial root user
• REMIND_HOUR: Hour of the day (in the given TIMEZONE) to send appointment reminders

Installation

Install dependencies

yarn install

Usage

To use the tas-server, the database must be prepared (with the necessary tables) and the server started. The GraphQL API can then be queried.

The database can be initialized with scripts in lib/data/setup-scripts/ (used in the yarn scripts below)

• setup-prod.js sets up all the tables, dropping any existing data (it will warn you)
• setup-dev.js sets up the tables and also adds sample data (also dropping existing data, without warning you)

The entry point file, lib/index.js, starts the server (lib/server/server.js).

The server can run in two modes: development and production.

Development and testing

Setup the database with sample data (clearing existing data; it will warn you) and start the server:

yarn develop

In development mode, the server is run with nodemon, which restarts the server any time a file is modified.

You can also start the server without adding/clearing sample data using

yarn start:dev

or just reset the database to only sample data (it will warn you) with

yarn setup:dev

Production

Setup

Setup the database tables (users, restrictions, appts, actions, config) first time only

yarn setup

Note: Running yarn setup will drop all existing database tables (it will warn you and ask for confirmation), so only run if looking for a fresh start.

This script will create a single entry in the config table using the DB_SETUP prefixed environemnt variables from .env. The application can not run unless there is an entry in the config table with values for each field.

The script will also create a single admin user named root with the password defined in the ROOT_USER_PW environment variable.

This user cannot be queried, deleted, or modified using the API. It is intended to be used to confirm and promote to admin the desired system administrator after he/she has registered. After this, root should not be used.

Starting the server

Start the server (with NODE_ENV set to production)

yarn start

Dates and Time Zones

The tas-server stores all dates in UTC and all time slot and hour values in the given TIMEZONE.

When received as input, time slot object { date, hour }, day of week, arrival window, and hour values are assumed to be in the given TIMEZONE. This includes data received from queries/mutation.

Querying the GraphQL API

Once the server is running, the GraphQL API will be available at http://localhost:PORT/graphql, with PORT as defined in .env.

For testing GraphQL queries, use GraphQL Playground, available at http://localhost:PORT/playground.

Note: The playground is available in development mode only.

JSON Web Tokens (JWTs)

Authentication and authorization in the tas-server uses JWTs in several locations, but primarily as access tokens.

Access token JWTs are signed by the backend with the SECRET_KEY from .env.

A signed, non-expired JSON Web Token must be included in the HTTP authorization header to access many of the resources.

Authorization : Bearer <JWT>

Where <JWT> is replaced by the JWT obtained from logging in (the login mutation).

Verification of the JWT (that it has been signed with the correct SECRET_KEY) allows access to all of the queries (authentication), though the userRole claim in the token is also checked to ensure the query can be performed by that given user (authorization).

Example implementation: The TAS Web App stores the JWT given on login in window.localStorage and includes it with every request to the tas-server API. 'Logging out' of the application removes the JWT from storage.

Unprotected Queries

Certain queries and mutations can be access without any JWT given:

• addUser - for registration
• login - obtain JWT
• sendResetPassLink - if password is forgotten
• resetPassword - following reset link

An Example (with GraphQL Playground)

Log in using a sample user

mutation {
  login(input: { email: "[email protected]", password: "dragonspark" })
}

This mutation will return a string, the JWT.

Include the JWT string received from the response in the HTTP HEADERS section (in the bottom of the playground) in the following form:

{ "Authorization": "Bearer eyJhbGciOiJIUzI1NiI..." } // string truncated for brevity

You can now access all endpoints until the token expires. Let's try out a simple me query.

{
  me {
    name
  }
}

This should return

{
  "data": {
    "me": {
      "name": "Jacob Brady"
    }
  }
}

Great; you're on your way.

REST API and Refresh Tokens

The tas-server exposes one REST endpoint, /auth-token.

This endpoint will respond with a signed JWT (auth/access token) if the request includes a valid refreshToken cookie. This cookie is set by the login GraphQL mutation. The refresh token is encrypted and stored on the user.

Reminders (src/reminders)

This version of the TAS server includes a service which sends reminder emails and SMS to users with appointments for the next day. Reminders are sent every day at the given REMIND_HOUR (environment variable).

Previously, the reminder system was a separate service which made the sendApptReminders mutation. This is cleaner if deploying the TAS with Docker; see the separate-reminders branch for this implementation.

Testing

Run the test suite with

yarn test

Tests were unforunately a quick-and-dirty addition to this project and thus are largely tests of each graphql resolver which make actual calls to the database. Thus data in the database give in .env will be overwritten when running tests so please ensure you have a test environment set up and do not run this on the live system. Additionally, you must call the following code in each test suite.

require('dotenv').config();
require('moment-timezone').tz.setDefault(process.env.TIMEZONE);

Linting

Uses ESLint; configuration defined in .eslintrc.js.

yarn lint

Deployment

The production TAS will be deployed using Docker. tas-server is one part of the two-piece TAS backend, the other part is the database.

The full TAS backend with tas-server as a submodule is exists as the tas-backend project. The full backend is deployed with Docker Compose.

Docker

The tas-server project can be run with Docker. Is is also on Docker Hub.

To start tas-server, run:

docker build -t tas-server .
docker run -p 4000:4000 tas-server

The default NODE_ENV (set in the Dockerfile) is development.

Production

Set the environment to production with

docker run -e NODE_ENV=production -p 4000:4000 tas-server

Database Setup

To set up the database, docker exec into the container running tas-server and run either yarn setup or yarn setup:dev.

docker exec -it tas-server bash
yarn setup
exit

Persisting Logs

The dockerized tas-server logs to the /tas-server/logs/ directory within the container. I recommend using named volumes to persist this data to the docker area.

For example:

docker run -v tas-server-logs:/tas-server/logs -p 4000:4000 tas-server

Then, log files can be found at /var/lib/docker/volumes/tas-server-logs/ on the host machine.

Docker Compose

The Dockerized tas-server is exciting when used with Docker Compose to simultaneously start, setup, and connect to a MariaDB database with a single command.

I've done this in the tas-backend project.

Project Organization

All JavaScript is located in lib/

lib/index.js is the entry point to run the application. It will start the server express server and expose the GraphQL endpoint. This is run by yarn start.

lib/data/

• Contains Sequelize models and model definitions for interacting with the database.
• Contains database connection configuration.
• setup-scripts/ contains database table setup code, run by yarn setup and yarn develop.

lib/logging/

• Logs to /logs/ directory (will be created if it does not exist).
• exceptions.log contains any uncaught exceptions.
• errors.log contains all server errors.
• combined.log contains all server requests, server error responses, GraphQL queries fired, and errors.
• verbose.log contains everything in combined.log with the addition of database queries.

lib/messaging/

• Contains all email and SMS sending code and templates (If you're updating the frontend colors or logo, you'll have to change these templates too.)
• Email is sent using Mailgun
• SMS is sent using Twilio

lib/graphql/

• Contains all GraphQL resolvers (helpers, input checking, errors...) and schema. There is a README here as well.

lib/rest/

• Contains all code for REST routes. Currently (and potentially forever), the only REST route is /auth-token, which gets an auth token using the refreshToken cookie.

lib/terminal-connection/

• Contains all code related to fetching data from the container terminal. Specifically:
  • Checking validity of container details.
  • Getting container size (for IMPORT_FULL appointments)

Built With

Node 10.7.0, using ECMAScript 2018 features.

This project relies on the following technologies, most included as npm packages.

• Express - Web server exposing the GraphQL API endpoint
• Mailgun - Email sending service
• Twilio - SMS sending service
• Apollo Server - Express middleware to facilitate GraphQL interactions
• Sequelize - Abstracting database interactions
• ESLint - JavaScript linting
• Nodemailer - Email sending
• jsonwebtoken - Signing and verifying JWTs
• Apollo Errors and Apollo Resolvers - Error management/formatting and easy resolver authentication by chaining
• node-cron - Daily appointment reminder sending

License

The TAS (and thus tas-server) was built for BCTC and is licensed under the GNU General Public License, Version 3.

See LICENSE.md for details.

Contributing

I don't have an official contribution guide, but welcome pull requests and any form of comments (submit an issue!); if you're interested in contributing, please get in touch.

Todo

There are a still few areas that need attention.

• Configure CORS
• Switch from Mailgun to client's SMTP server (completed in bctc-prod branch)
• Switch to MSSQL (per client request) (completed in bctc-prod branch)

---

Copyright (C) 2020 KCUS, Inc.