Deutsche Bahn Price Search Backend

This is a backend service for searching Deutsche Bahn train prices and connections. It's designed as a supporting microservice for the main application at bahn.vibe.

Overview

This Express.js backend provides REST API endpoints to:

• Search for train stations dynamically using the Deutsche Bahn API
• Find the best prices for train connections across multiple dates
• Return detailed connection information including departure/arrival times

Features

• Dynamic Station Search: Automatically resolves station names to Deutsche Bahn station IDs
• Multi-day Price Search: Search for best prices across multiple consecutive days
• Flexible Configuration: Support for different travel classes, connection types, and transfer limits
• Real-time Data: Fetches live pricing data from Deutsche Bahn's official API
• CORS Enabled: Ready for cross-origin requests from frontend applications

Installation

# Clone the repository
git clone <repository-url>
cd bahn-backend

# Install dependencies
npm install

# Start the server
npm start

The server will start on port 3000 by default (or the port specified in the PORT environment variable).

API Endpoints

1. Search Station

Search for a train station by name or partial name.

Endpoint: GET /api/search-station

Parameters:

• query (string, required): Station name or partial name to search for

Example:

curl "http://localhost:3000/api/search-station?query=München"

Response:

{
  "id": "A=1@O=München Hbf@X=11558339@Y=48140229@U=80@L=8000261@B=1@p=1751482402@i=U×008020347@",
  "name": "München Hbf"
}

2. Search Prices

Search for train connections and prices across multiple dates.

Endpoint: POST /api/search-prices

Request Body:

{
  "start": "München",
  "ziel": "Berlin",
  "abfahrtab": "2025-01-30",
  "klasse": "KLASSE_2",
  "schnelleVerbindungen": false,
  "nurDeutschlandTicketVerbindungen": false,
  "maximaleUmstiege": "9",
  "dayLimit": 3
}

Parameters:

• start (string, required): Departure city/station name
• ziel (string, required): Destination city/station name
• abfahrtab (string, required): Start date in YYYY-MM-DD format
• klasse (string): Travel class (KLASSE_1 or KLASSE_2)
• schnelleVerbindungen (boolean): Prefer fast connections
• nurDeutschlandTicketVerbindungen (boolean): Deutschland-Ticket only connections
• maximaleUmstiege (string): Maximum number of transfers (e.g., "9")
• dayLimit (number): Number of consecutive days to search (default: 3)

Example:

curl -X POST http://localhost:3000/api/search-prices \
  -H "Content-Type: application/json" \
  -d '{
    "start": "München",
    "ziel": "Berlin",
    "abfahrtab": "2025-01-30",
    "klasse": "KLASSE_2",
    "schnelleVerbindungen": false,
    "nurDeutschlandTicketVerbindungen": false,
    "maximaleUmstiege": "9",
    "dayLimit": 3
  }'

Response:

{
  "2025-01-30": {
    "preis": 29.90,
    "info": "30.01.2025, 08:15:00 München Hbf -> 30.01.2025, 12:28:00 Berlin Hbf",
    "abfahrtsZeitpunkt": "2025-01-30T07:15:00.000Z",
    "ankunftsZeitpunkt": "2025-01-30T11:28:00.000Z",
    "allIntervals": [...]
  },
  "2025-01-31": { ... },
  "2025-02-01": { ... },
  "_meta": {
    "startStation": {
      "id": "A=1@O=München Hbf@...",
      "name": "München Hbf"
    },
    "zielStation": {
      "id": "A=1@O=Berlin Hbf@...", 
      "name": "Berlin Hbf"
    },
    "searchParams": {
      "klasse": "KLASSE_2",
      "maximaleUmstiege": 9,
      "schnelleVerbindungen": false,
      "nurDeutschlandTicketVerbindungen": false
    }
  }
}

Travel Classes

• KLASSE_1: First class
• KLASSE_2: Second class

Error Handling

The API returns appropriate HTTP status codes:

• 200: Success
• 400: Bad request (missing required parameters)
• 404: Station not found
• 500: Internal server error

Error responses include details:

{
  "error": "Station not found",
  "message": "Start station \"InvalidStation\" not found"
}

Integration

This backend is designed to work with the main bahn.vibe application.

Development

Project Structure

├── server.js          # Main application file
├── package.json       # Dependencies and scripts
└── README.md         # This file

Dependencies

• express: Web framework
• cors: Cross-origin resource sharing
• body-parser: Request body parsing
• axios: HTTP client (imported but can be removed if not used elsewhere)

Environment Variables

• PORT: Server port (default: 3000)

Contributing

This backend service is part of the larger bahn.vibe project. Please refer to the main repository for contribution guidelines and project roadmap.

Notes

• This service makes requests to Deutsche Bahn's official APIs
• Rate limiting may apply from Deutsche Bahn's side
• The service includes appropriate headers to mimic browser requests
• Station IDs are used as-is from the Deutsche Bahn API without normalization