THSR Auto Buy

Features

• Implement both frontend and serverless backend for reserving booking ticket
• Managing discounts and train searching
• Auto calculate ticket start booking date
• Update train discounts and special days everyday with cron-job
• Booking Ticket at every exactly 00:00:00 and retry until 2 AM

Apps and Packages

Apps

• web: Full-stack app for reserving ticket and searching trains with discounts
• functions: Serverless backend for crawling and booking tickets with

Packages

• crawler: crawling discounts and special days from thsr website
• database: database models
• taiwan-id: taiwanese id validator and generator
• tdx-api: tdx api
• ticket-flow: booking thsr ticket flow
• eslint-config-custom: eslint configurations (includes eslint-config-next and eslint-config-prettier)
• tsconfig: tsconfig.jsons used throughout the monorepo

Each package/app is 100% TypeScript.

Setup

Build

To build all apps and packages, run the following command:

pnpm run build

Develop

To develop frontend, run the following command:

pnpm run dev

Difficulties and Experience

• Handled deploy firebase functions
  • Firebase not support monorepo
  • Prisma needed to set binaryTargets for running on Firebase functions
• Handled booking ticket flow with cookies validation
• Handled cleaning crawled data
• Handled retry mechanism
• Handled locale timezone (firebase cloud functions is run at utc+0 and frontend is utc+8)
• Tried many free databases, finally choose PostgreSQL with Supabase due to:
  • Firebase firestore: it's not type safe enough and it is annoying to handle TimeStamp in firestore and convert it to Date
  • MySQL with PlanetScale: Planet doesn't support foreign keys
  • PostgreSQL with fly.io: it is a mistake..., it is not supported outside applications to connect