Hotel Booking Integration using MuleSoft

Overview

This project implements a robust API-Led Connectivity solution to retrieve and transform hotel booking data. It follows a three-layer architecture (System, Process, Experience) to decouple data access from business logic and client consumption.

The solution is designed to be production-ready, featuring advanced error handling, caching, content negotiation, and structured logging.

Architecture

The solution consists of three distinct API layers communicating via HTTP:

Layer	API Name	Port	Description
System	sys-booking-api	8081	Data Access Layer: Reads raw XML data from bookings.xml and guests.xml, filters by Reference ID, and handles data validation.
Process	pro-booking-api	8082	Logic Layer: Orchestrates calls to the System API, aggregates guest data, transforms XML to JSON, and implements Caching.
Experience	exp-booking-api	8083	Channel Layer: Client-facing proxy handling Content Negotiation (XML/JSON), Global Error Mapping, and Request Logging.

Key Features

1. Core Logic & Transformation

• Complex DataWeave: Transforms flat XML structures into nested JSON objects with type coercion (Strings to Numbers).
• Data Aggregation: Merges customer details and guest lists into a single booking object.
• Resilient Filtering: System API logic handles invisible whitespace (trim) and empty datasets to prevent false positives.

2. Advanced Error Handling

• Global Error Handler: Implemented across all three layers.
• Status Code Mapping: Automatically maps downstream errors (e.g., empty XML results) to correct HTTP 404 Not Found responses instead of generic 500 Server Errors.
• Clean Responses: Returns user-friendly JSON error messages: { "error": { "code": "NOT_FOUND", ... } }.

3. Observability

• Structured Logging: Logs events at the start and end of every flow in JSON format.
• Correlation ID: Propagates correlationId across the entire API chain for full traceability.

4. Bonus Features (Implemented)

• Caching Strategy: The Process API caches responses for 5 minutes based on the Booking Reference ID. Repeated requests do not hit the System API or file system.
• Content Negotiation: The Experience API supports both JSON and XML output.
  • Default: JSON
  • Header Accept: application/xml: Returns XML wrapped in <Booking> tags.
• Configuration Management: All HTTP ports (8081, 8082, 8083) are externalized in config.yaml to avoid hardcoding.

Setup & Usage

Prerequisites

• Anypoint Studio 7.x
• Mule Runtime 4.x

Installation

1. Import the project into Anypoint Studio.
2. Ensure the src/main/resources/data folder contains the source files:
   • bookings.xml
   • guests.xml
3. Right-click the project -> Run As -> Mule Application.

Testing Endpoints

1. Happy Path (Valid Booking)

• URL: http://localhost:8083/api/v1/bookings/BKG-1002
• Method: GET
• Result: 200 OK with full JSON details.

2. Sad Path (Missing Booking)

• URL: http://localhost:8083/api/v1/bookings/BKG-9999
• Method: GET
• Result: 404 Not Found with structured error JSON.

3. Caching Test

• Make a request to BKG-1001.
• Check Console: Logs appear for Experience, Process, and System APIs.
• Make the same request again immediately.
• Check Console: System API logs are missing, proving the response came from the Cache.

4. XML Output Test

• URL: http://localhost:8083/api/v1/bookings/BKG-1002
• Header: Accept: application/xml
• Result: Response is returned in XML format.

File Structure

• /src/main/mule:
  • global.xml: Shared configuration (Error Handlers, Object Store).
  • sys-booking-api.xml: System Layer flow.
  • pro-booking-api.xml: Process Layer flow.
  • exp-booking-api.xml: Experience Layer flow.
• /src/main/resources:
  • config.yaml: Externalized properties.
  • /data: XML source files.