Payment Gateway

This APP simulates the sending of a ETH transaction hash (TXHash) as payment, and confirms it against Etherscan API.

Demo

Tech stack

• Elixir;
• Phoenix Framework;
• PostgreSQL;
• NPM;
• Webpack;
• ReactJS and Redux; and
• Sass

Installation

Assuming that you already have the technologies above pre-installed, clone the repository and install dependencies.

# Clone this repository
$ git clone https://[email protected]/douglasxgabriel/payment_gateway.git

# Go into the repository
$ cd payment_gateway

# Install project dependencies
$ mix deps.get

# Go into UI app
$ cd apps/ui

# Install npm dependencies
$ npm install

Also, you may want to configure your local database. To do this you must go into the following files and update the data.

• apps/core/config/config.exs
• apps/core/config/dev.exs
• apps/core/config/test.exs
• apps/payment_checker/config/test.exs

Tests

Before you can run the tests you will need to prepare your database

$ MIX_ENV=test mix ecto.create

$ MIX_ENV=test mix ecto.migrate

It's possible to run tests from the root dir, this way it will run tests for all the umbrella apps.

# in payment_gateway root
$ mix test

Or it's also possible to run tests for a specific app.

# Go into app directory
$ cd apps/<app>

$ mix test

Usage

To run the APP you can go into UI app and run phoenix.server

# Go into UI app
$ cd apps/ui

# Run Phoenix Server
$ mix phoenix.server

This way it will also run webpack-cli command that watches file changes inside payment_gateway/apps/ui/web/static. But you can also run the app from root directory and start webpack by yourself.

# In payment_gateway root

# Run Phoenix Server
$ mix phoenix.server

# Run webpack-cli
$ webpack-cli --config webpack.config.js --watch --colors

Then your server should be running on http://localhost:4000

Umbrella apps

This project contains four umbrella apps, each one with its own responsability:

Core

This project provides database configuration such as Migrations, Schemas and Repo, as well as Management modules to interact with entities.

By centralizing database logic in this single project, other projects are allowed to use the shared routines to interact with database. It strategy provides a better code reusability and improves the maintenance.

EthereumService

This project provides modules to communicate with Etherscan API.

Once that to interact with a API is a specialized task, where the consumer needs to know a lot about the provider, split this logic into a single app is a good strategy since it can provide a common interface to for the others that can ignore the particularities of the API.

PaymentChecker

This project contains a worker that is called constantly after a amount of time and uses the Core app to retrieve unconfirmed payments and uses EthereumService app to check if the payment was confirmed in Etherscan API.

This project also abstracts a specialized task that can be abstracted from the other projects.

UI

This project provides ways to communicate with external users, both by a REST API or webpage.

Here is abstracted another specialized taks that is to communicate with external users and put together all apps from the umbrella.

Features

• Record a payment;
• List all recorded payments;
• Confirm a payment; Payment status could be:
  • Error;
  • OK;
  • Undefined; When has this status, a worker will verify again after a fixed amount of time;

TODOs

• Verify TXHash uniquiness for Payments.