RoomBookings (WIP!)

Overview

A basic Proof of Concept (PoC) system that allows users to search for and book rooms that are added by hosts

Description

Hosts are able to add rooms, which consist of one or more beds (single, double, bunk, king size, queen size) and a number of facilities such as wifi, free parking. Rooms have a check-in by and check-out by time and are available to book by (joined) users 365 days a year. Double and bunk beds can hold 1 or 2 guests and all other beds hold 1 guest.

Hosts can also specify a daily price, (optionally) multiple duration discounts and (optionally) a mimimum and maximum booking duration on rooms.

Bookings can be cancelled by hosts but not created or ammended. Rooms cannot be modified or deleted once created.

Any registered user can (optionally) become a host by adding a room. Hosts are able to view a list of their rooms and view bookings for rooms.

Visitors and users are able to search for available rooms by location, price, date range, number of guests, room facilities and number of beds.

Visitors can join the system to become a User and book a room for their desired dates. Bookings can be cancelled by users but not ammended. Users can view a list of their future and past bookings, including cancelled bookings and view details for each booking. Exact locations of rooms are only provided to the User once a booking has been made.

Users and Hosts should be notified by email where appropriate

Note: This is a basic PoC, so a number of features such as payment and seasonal room rates do not need to be considered.

Architecture

A Clean Architecture approach will be used to separate concerns into distinct layers:

• Domain (enterprise business logic)
• Application (application business logic, use cases),
• Interface (ui, apis, gateways)
• Infrastructure (persistence, external interfaces)

Domain Driven Design (DDD) will be used to build a Ubiquitous Language, identify Bounded Contexts and model AggregateRoots in the domain layer

Bounded Contexts will be implemented as MicroServices, to provide a system that is easy to scale and fast to develop.

Use Cases will be implemented using Command Query Responsibility Segregation (CQRS) to provide a separation of concerns between a businessl logic orientated write model and an efficient and flexible read model.

For system wide asynchronous communications Integration Events on an Event Bus will be used. These will also use an Inbox/Outbox pattern for reliable message delivery

Domain Events will be used for inter aggregate communication within each microservice

Repository and Unit Of Work patterns for abstracting write side persistence

Unit Testing, Functional Testing and End To End Smoke Testing will be employed

Technology

.NET 7 for all application development Sql Server and Entity Framework for persistence MassTransit for distributed application development and inbox/outbox pattern implementation RabbitMq for event bus MediatR for CQRS and domain events Yarp for gateways Serilog for logging FluentValidation for validation Autofac for dependency injection (DI) AutoMapper for convention-based object mapping xUnit for testing

Domain Analysis

Definitions (Ubiquitous Language)

Visitor - A person interacting with the system that has not joined

User - A person that has registered to join the system

Host - A User that can add Rooms to the system

Room - A room that has a Location, Facilities, check-in/check-out times and contains 1 or more Beds

Location - A propery name and address

Guest - A person staying in a Room

Facility - Facilities that a room has to offer. These are Free Wifi, Free Parking, Air Con, Satellite Tv

Booking - A reservation on a Room by a User between 2 dates

Bed - A bed of type Single, Double, Bunk, King Size or Queen Size.

Notification - An email to a User or Host providing information on an action

Use Cases

Search Rooms

View Room

Join User

Create User Booking

Cancel User Booking

List User Bookings

View User Booking

Become Host

Add Host Room

List Host Rooms

List Host Bookings

View Host Room

View Host Booking

Cancel Host Booking

Domain Design

Room Service (Bounded Context)

Room - AggregateRoot

• Beds - List
  • BedType - Enum
    • Single
    • Double
    • Bunk
    • King
    • Queen
• Facilities - ValueObject
  • HasFreeWifi - bool
  • HasFreeParking - bool
  • HasAirCon - bool
  • HasSatelliteTv - bool
• Bookings - List
  • UserId - int
  • StartDate - DateTime
  • EndDate - DateTime
  • GuestCount - int
  • IsCancelled - bool
• BookingDurationDiscounts - List
  • DurationDays - int
  • DiscountPercentage - int
• Address - ValueObject
  • Address1 - string
  • Address2 - string (optional)
  • City - string
  • Region - string
  • Country - Enum
  • PostalCode - string
• MinimumBookingDurationDays - int (default = 1)
• MaximumBookingDurationDays - int (optional)
• DailyPrice - double

User Service (Bounded Context)

User - AggregateRoot

• FirstName - string
• LastName - string
• EmailAddress - string
• IsHost - bool