Fawry Clone

Course: Advanced Software Engineering

Faculty of Computer and Artificial Intelligence - Cairo University

Table of contents

• Project Overview
  • Normal user
  • Admin
  • Features
• Technical details
• Important Notes
  • Initial service providers
  • Adding a new service provider
  • Authentication
  • Bypassing authentication to facilitate testing
  • Protected endpoints

Project overview

This is a clone of Fawry, an e-payments and digital finance solution in Egypt.

There are two types of users who can use this system:

1. Normal user
2. Admin

Normal user

This user can pay for the services provided by the different service providers in the system. They have a wallet which they can use in payment, and they can issue refund requests for the payment transactions they make.

Admin

This user can respond to refund requests made by normal users, they can add discounts to the available services, and see all recorded transactions.

Features

1. Users and admins can sign up using an email, a username and a password.
2. Users can search for service providers.
3. Users can pay for services.
4. Users can make refund requests.
5. Users can add funds to their wallet.
6. Admins can add discounts to services.
7. Admins can see all transactions made by normal users.
8. Admins can respond to refund requests made by normal users.

Technical details

The whole system is divided into 7 main subsystems:

• The authentication subsystem
• The payment subsystem
• The service providers subsystem
• The refunds subsystem
• The wallet subsystem
• The discounts subsystem
• The transactions subsystem

Each subsystem has one minimal and clear goal that it achieves by exposing its functionality through a bunch of REST endpoints.

Each subsystem is contained in a package designed in the following manner:

classDiagram
class Controller {
    -repository: Repository
    +endpoint()
}
class Repository {
    <<interface>>
    +create()
    +read()
    +update()
    +delete()
}
Controller o--> Repository
class InMemoryRepository {
    -data: List
    +create()
    +read()
    +update()
    +delete()
}
Repository <|.. InMemoryRepository
class Model {
    -field: Object
}
InMemoryRepository *-- Model

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The package common as its name suggests contains all classes used by multiple controllers, such as exception and exception handling classes, and the input validation class Validator.

Important notes

Initial service providers

Initially, there are 3 service providers:

• WE
• Vodafone
• Etisalat

For every service, no matter it's type (e.g. donation, landline, etc.) there will be a concrete class that extends the ServiceProvider abstract class and declares all the inputs it needs to provide its services.

Adding a new service provider

A developer can easily add a new service provider by following the simple steps below:

1. Go to the package eg.edu.cu.fcai.swe.fawry.provider.providers.
2. Create a new class for the new provider to be added.
3. Make the provider class extend the ServiceProvider class.
4. Create a constructor that takes the following parameters:
   • String id
   • String name

and pass them to the super(String id, String name) constructor call.

The id should be unique across all service providers.

The name is the service name that end users will see when they are searching for service providers.

5. Implement the boolean handle(Map<String, Object> paymentForm) method.

Put all checks on the required form fields (found in paymentForm) here, and of course, the calls to the service provider's API.

Authentication

This system implements an actual authentication system, so when you create a user account or an admin account you will get a token in return (in the response body) that you will have to put in the Authorization header of requests to protected endpoints.

The value of the Authorization header should follow this format:

Bearer <TOKEN>

where <TOKEN> is the actual token string returned from the sign-up/in endpoint.

Bypassing authentication to facilitate testing

If you want to bypass token validation, there is a dummy user account and a dummy admin account created initially that you can use by turning on debug mode.

To turn on debug mode, follow these simple steps:

1. Go to the class eg.edu.cu.fcai.swe.fawry.common.Validator

2. Find this line:

private static final boolean DEBUG_MODE = false;

3. Change the value of DEBUG_MODE to true.

Now, you should be able to access all endpoints without the need to create user or admin accounts.

Protected endpoints

The following endpoints are protected, which means you need to be an authenticated user or admin to access them.

If the previously mentioned DEBUG_MODE is set to false, you will need to be an authenticated admin to access the following endpoints:

POST /discount/{{providerId}}

POST /discount

GET  /refund/all

POST /refund/response

GET  /transaction/all

and an authenticated user to access the following endpoints:

POST /pay/{{providerId}}

GET  /wallet

POST /wallet

GET  /refund/request

POST /refund/request

GET  /transaction