EV Charging Station Booking System

A comprehensive EV charging station booking system with 4 main components: Web Service API, Web Application (Backoffice), Mobile Application, and NoSQL Database.

Architecture Overview

The system follows a service-oriented architecture where the Web Service API serves as the central business logic layer, with web and mobile applications acting as UI-only clients.

┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   Web App       │    │   Mobile App    │    │   External      │
│  (Backoffice)   │    │   (Android)     │    │   Integrations  │
└─────────────────┘    └─────────────────┘    └─────────────────┘
         │                       │                       │
         └───────────────────────┼───────────────────────┘
                                 │
                    ┌─────────────────┐
                    │   Web Service   │
                    │     (API)       │
                    └─────────────────┘
                                 │
                    ┌─────────────────┐
                    │   MongoDB       │
                    │  (NoSQL DB)     │
                    └─────────────────┘

Components

1. Web Service API (C# ASP.NET Core)

• Location: src/EVChargingStation.API/
• Technology: ASP.NET Core 8.0 Web API
• Database: MongoDB
• Authentication: JWT Bearer Token
• Documentation: Swagger/OpenAPI

Key Features:

• User authentication and authorization
• Charging station management
• Booking system with real-time availability
• Role-based access control (Admin, Operator, EVOwner, BackofficeUser)
• RESTful API design
• CORS enabled for cross-origin requests

API Endpoints:

• POST /api/auth/login - User authentication
• POST /api/auth/register - User registration
• GET /api/auth/profile - User profile
• GET /api/chargingstations - List all stations
• GET /api/chargingstations/nearby?lat={lat}&lon={lon}&radius={km} - Find nearby stations
• POST /api/chargingstations - Create new station (Admin/Operator)
• GET /api/bookings - List all bookings (Admin/Backoffice)
• POST /api/bookings - Create new booking
• PATCH /api/bookings/{id}/confirm - Confirm booking (Operator)

2. Web Application (ASP.NET Core MVC)

• Location: src/EVChargingStation.Web/
• Technology: ASP.NET Core 8.0 MVC
• Purpose: Backoffice management and operator interface

Features:

• Dashboard with system statistics
• User management
• Charging station management
• Booking management and monitoring
• Operator tools for booking confirmation
• Responsive web design

User Roles:

• Admin: Full system access, user management, station management
• BackofficeUser: Booking management, reporting, customer support
• Operator: Station management, booking confirmation for their stations

3. Mobile Application (Android)

• Location: mobile/EVChargingStationApp/
• Technology: Android (Kotlin), SQLite
• Architecture: MVVM with Repository pattern

Features for EV Owners:

• User account management
• Interactive map with charging stations
• Station search and filtering
• Reservation system with QR code generation
• Booking history and status tracking
• Real-time notifications
• Offline data caching

Features for Operators:

• Booking confirmation via QR scanning
• Station status updates
• Connector availability management
• Performance metrics

Key Technologies:

• Room Database: Local SQLite caching
• Retrofit: HTTP API client
• Google Maps: Location services and mapping
• ZXing: QR code generation/scanning
• Hilt: Dependency injection
• Navigation Component: In-app navigation

4. Data Models

Core Entities:

• User: Authentication and profile information
• ChargingStation: Station details, location, amenities
• Connector: Charging connectors with types and power ratings
• Booking: Reservation details with status tracking

User Roles:

• Admin: System administration
• EVOwner: End users who book charging stations
• Operator: Charging station operators
• BackofficeUser: Customer service and support

Booking Status Flow:

Pending → Confirmed → InProgress → Completed
   ↓         ↓           ↓
Cancelled  Cancelled  NoShow

Technology Stack

Backend (.NET)

• Framework: ASP.NET Core 8.0
• Database: MongoDB (NoSQL)
• Authentication: JWT Bearer Tokens
• API Documentation: Swagger/OpenAPI
• Logging: Built-in ASP.NET Core logging
• Hosting: IIS Compatible

Frontend (Web)

• Framework: ASP.NET Core MVC
• UI: Bootstrap 5, jQuery
• Session Management: ASP.NET Core Sessions
• HTTP Client: HttpClient with custom API service

Mobile (Android)

• Language: Kotlin
• Database: SQLite with Room ORM
• Architecture: MVVM + Repository
• DI: Dagger/Hilt
• HTTP: Retrofit + OkHttp
• Maps: Google Maps SDK
• QR Codes: ZXing library

Configuration

API Configuration (appsettings.json)

{
  "DatabaseSettings": {
    "ConnectionString": "mongodb://localhost:27017",
    "DatabaseName": "EVChargingStationDB"
  },
  "JwtSettings": {
    "Secret": "your-secret-key-here"
  }
}

Web App Configuration

{
  "ApiSettings": {
    "BaseUrl": "https://localhost:7000/api"
  }
}

Mobile App Configuration

• API Base URL: Configured in build.gradle
• Google Maps API Key: Set in manifest
• Local database: Automatic SQLite setup

Installation & Setup

Prerequisites

• .NET 8.0 SDK
• MongoDB (local or cloud)
• Android Studio (for mobile development)
• Google Maps API Key

Running the API

cd src/EVChargingStation.API
dotnet run

API will be available at https://localhost:7000

Running the Web App

cd src/EVChargingStation.Web
dotnet run

Web app will be available at https://localhost:5000

Building the Mobile App

1. Open Android Studio
2. Import the project from mobile/EVChargingStationApp
3. Add Google Maps API key to local.properties
4. Build and run on device/emulator

Database Schema

Users Collection

{
  "_id": "ObjectId",
  "firstName": "string",
  "lastName": "string",
  "email": "string",
  "phoneNumber": "string",
  "passwordHash": "string",
  "role": "enum",
  "isActive": "boolean",
  "createdAt": "datetime",
  "updatedAt": "datetime"
}

ChargingStations Collection

{
  "_id": "ObjectId",
  "name": "string",
  "description": "string",
  "location": {
    "latitude": "double",
    "longitude": "double"
  },
  "address": "string",
  "operatorId": "string",
  "connectors": [
    {
      "id": "string",
      "type": "enum",
      "power": "decimal",
      "isAvailable": "boolean",
      "status": "enum"
    }
  ],
  "status": "enum",
  "amenities": ["string"],
  "openingHours": "string",
  "pricePerKWh": "decimal",
  "createdAt": "datetime",
  "updatedAt": "datetime"
}

Bookings Collection

{
  "_id": "ObjectId",
  "userId": "string",
  "stationId": "string",
  "connectorId": "string",
  "startTime": "datetime",
  "endTime": "datetime",
  "status": "enum",
  "qrCode": "string",
  "energyConsumed": "decimal",
  "totalCost": "decimal",
  "notes": "string",
  "confirmedBy": "string",
  "confirmedAt": "datetime",
  "createdAt": "datetime",
  "updatedAt": "datetime"
}

Security

• Authentication: JWT tokens with role-based claims
• Authorization: Role-based access control throughout the system
• API Security: HTTPS only, CORS configuration
• Mobile Security: Android Keystore for token storage
• Database: MongoDB with authentication enabled
• Input Validation: Server-side validation for all inputs

Testing

API Testing

• Use Swagger UI at /swagger endpoint
• Postman collection available for comprehensive testing
• Unit tests for services and controllers

Web App Testing

• Integration tests for MVC controllers
• UI tests for critical user journeys

Mobile App Testing

• Unit tests for ViewModels and repositories
• UI tests with Espresso
• Integration tests for API communication

Deployment

Production Considerations

• API: Deploy to IIS or Azure App Service
• Database: MongoDB Atlas or self-hosted MongoDB cluster
• Web App: Deploy to IIS or Azure App Service
• Mobile: Publish to Google Play Store

Environment Configuration

• Use environment-specific configuration files
• Secure secret management (Azure Key Vault, etc.)
• Load balancing for high availability
• CDN for static assets

Future Enhancements

• Real-time notifications via SignalR
• Payment integration (Stripe, PayPal)
• Advanced analytics and reporting
• Multi-language support
• iOS mobile application
• Third-party station integrations
• Smart charging features
• Load balancing and auto-scaling

Contributing

1. Fork the repository
2. Create a feature branch
3. Implement changes with tests
4. Submit a pull request
5. Ensure all CI/CD checks pass

License

This project is licensed under the Apache 2.0 License - see the LICENSE file for details.