Final Project Exam: FPT Customer Chatbot - Backend API System

Overview

Field	Value
Course	Building Monolith API with FastAPI
Project Name	fpt-customer-chatbot-api
Duration	360 minutes (6 hours)
Passing Score	70%
Total Points	100
Framework	Python 3.10+, FastAPI, SQLAlchemy, SQLite, Pydantic, pytest

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Description

You have been hired as a Backend Engineer at FPT Software, tasked with building the Backend API Layer for the FPT Customer Service Chatbot system.

This exam builds upon the AI Core developed in the LangGraph and Agentic AI module. Your task is to create a production-ready FastAPI backend that:

1. Provides REST API endpoints for the chatbot system
2. Implements database persistence with SQLAlchemy
3. Handles authentication and authorization
4. Integrates with the AI Core (from LangGraph module)
5. Implements proper error handling and logging

:::note Prerequisite This exam assumes you have completed (or have access to) the AI Core from the LangGraph and Agentic AI module exam. You will integrate the AI agents with your FastAPI backend. :::

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Objectives

By completing this exam, you will demonstrate mastery of:

• FastAPI Fundamentals: Building REST APIs with proper routing and request handling
• Database Modeling: Designing and implementing SQLAlchemy models
• CRUD Operations: Implementing Create, Read, Update, Delete operations
• Dependency Injection: Using FastAPI's dependency injection system
• Authentication: Implementing JWT-based authentication
• Input Validation: Using Pydantic for request/response validation
• Error Handling: Implementing proper HTTP error responses
• Unit Testing: Writing tests with pytest

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Problem Description

Build the Backend API for the FPT Customer Service Chatbot named fpt-customer-chatbot-api that includes:

Component	Responsibilities
Ticket API	REST endpoints for support ticket CRUD operations
Booking API	REST endpoints for meeting room booking CRUD operations
Chat API	Endpoints to interact with the AI chatbot core
User API	User registration and authentication
Database Layer	SQLAlchemy models and database session management

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Prerequisites

• Completed FastAPI module assignments (recommended)
• Python 3.10+ with virtual environment
• SQLite (bundled with Python)
• AI Core from LangGraph module (or mock implementation for standalone testing)

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Technical Requirements

Environment Setup

• Python 3.10 or higher
• Required packages:
  • fastapi >= 0.100.0
  • uvicorn >= 0.23.0
  • sqlalchemy >= 2.0.0
  • pydantic >= 2.0.0
  • python-jose[cryptography] >= 3.3.0
  • passlib[bcrypt] >= 1.7.0
  • pytest >= 7.0.0
  • httpx >= 0.24.0

Database Schema

Implement the following tables using SQLAlchemy:

User Table:

Column	Type	Constraints
id	Integer	Primary Key, Auto-increment
email	String	Unique, Required
hashed_password	String	Required
full_name	String	Required
phone	String	Optional
is_active	Boolean	Default: True
created_at	DateTime	Auto-set

Ticket Table:

Column	Type	Constraints
id	Integer	Primary Key, Auto-increment
ticket_id	String	Unique, Auto-generated UUID
content	String	Required
description	Text	Optional
user_id	Integer	Foreign Key to User
status	Enum	Pending/InProgress/Resolved/Canceled
created_at	DateTime	Auto-set
updated_at	DateTime	Auto-update

Booking Table:

Column	Type	Constraints
id	Integer	Primary Key, Auto-increment
booking_id	String	Unique, Auto-generated UUID
reason	String	Required
time	DateTime	Required, must be future
user_id	Integer	Foreign Key to User
note	Text	Optional
status	Enum	Scheduled/Finished/Canceled
created_at	DateTime	Auto-set
updated_at	DateTime	Auto-update

Conversation Table:

Column	Type	Constraints
id	Integer	Primary Key, Auto-increment
conversation_id	String	Unique, Auto-generated UUID
user_id	Integer	Foreign Key to User
created_at	DateTime	Auto-set
updated_at	DateTime	Auto-update

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Tasks

Task 1: Project Setup & Database Models (15 points)

Time Allocation: 60 minutes

Set up the FastAPI project structure and implement database models.

Requirements:

1. Create project structure following FastAPI best practices
2. Implement SQLAlchemy models for all tables (User, Ticket, Booking, Conversation)
3. Create database session management with dependency injection
4. Implement Pydantic schemas for request/response validation
5. Set up Alembic migrations (optional but recommended)

Deliverables:

• models/ directory with all SQLAlchemy models
• schemas/ directory with all Pydantic schemas
• database.py - Database connection and session management
• config.py - Application configuration

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Task 2: Authentication & Authorization (20 points)

Time Allocation: 90 minutes

Implement JWT-based authentication system.

Requirements:

1. User Registration endpoint:

   • POST /api/v1/auth/register
   • Hash passwords using bcrypt
   • Return user info (without password)

2. User Login endpoint:

   • POST /api/v1/auth/login
   • Validate credentials
   • Return JWT access token

3. Token Verification:

   • Create get_current_user dependency
   • Protect endpoints with authentication
   • Handle token expiration

4. User Profile endpoint:

   • GET /api/v1/users/me
   • Return current user info

Deliverables:

• routers/auth.py - Authentication endpoints
• routers/users.py - User endpoints
• utils/security.py - JWT and password utilities
• dependencies.py - Shared dependencies

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Task 3: Ticket API Implementation (20 points)

Time Allocation: 90 minutes

Implement full CRUD operations for support tickets.

Requirements:

1. Create Ticket:

   • POST /api/v1/tickets
   • Requires authentication
   • Auto-generate ticket_id (UUID)
   • Set initial status to "Pending"

2. List Tickets:

   • GET /api/v1/tickets
   • Support pagination (skip, limit)
   • Filter by status (optional)
   • Return only user's tickets

3. Get Ticket:

   • GET /api/v1/tickets/{ticket_id}
   • Return 404 if not found
   • Ensure user owns the ticket

4. Update Ticket:

   • PUT /api/v1/tickets/{ticket_id}
   • Allow status transitions only
   • Validate status transitions

5. Cancel Ticket:

   • DELETE /api/v1/tickets/{ticket_id}
   • Soft delete (change status to Canceled)

Deliverables:

• routers/tickets.py - Ticket endpoints
• crud/tickets.py - Ticket CRUD operations
• Unit tests for ticket endpoints

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Task 4: Booking API Implementation (20 points)

Time Allocation: 90 minutes

Implement full CRUD operations for meeting room bookings.

Requirements:

1. Create Booking:

   • POST /api/v1/bookings
   • Requires authentication
   • Validate time is in the future
   • Auto-generate booking_id (UUID)

2. List Bookings:

   • GET /api/v1/bookings
   • Support pagination
   • Filter by status and date range
   • Return only user's bookings

3. Get Booking:

   • GET /api/v1/bookings/{booking_id}
   • Return 404 if not found

4. Update Booking:

   • PUT /api/v1/bookings/{booking_id}
   • Allow updates only for "Scheduled" bookings
   • Validate new time is in future

5. Cancel Booking:

   • DELETE /api/v1/bookings/{booking_id}
   • Soft delete (change status to Canceled)

Deliverables:

• routers/bookings.py - Booking endpoints
• crud/bookings.py - Booking CRUD operations
• Unit tests for booking endpoints

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Task 5: Chat API & AI Integration (15 points)

Time Allocation: 60 minutes

Create endpoints to interact with the AI chatbot core.

Requirements:

1. Start Conversation:

   • POST /api/v1/chat/conversations
   • Create new conversation record
   • Initialize AI graph with user context

2. Send Message:

   • POST /api/v1/chat/conversations/{conversation_id}/messages
   • Forward message to AI core
   • Return AI response
   • Handle HITL interrupts

3. Confirm Action (for HITL):

   • POST /api/v1/chat/conversations/{conversation_id}/confirm
   • Resume interrupted operations
   • Accept "confirm" or "cancel"

4. Get Conversation History:

   • GET /api/v1/chat/conversations/{conversation_id}
   • Return all messages in conversation

:::info AI Integration If the AI Core is not available, implement mock responses that simulate the multi-agent behavior. :::

Deliverables:

• routers/chat.py - Chat endpoints
• services/chat_service.py - AI integration service
• services/ai_adapter.py - Adapter for AI Core (or mock)

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Task 6: Error Handling & Testing (10 points)

Time Allocation: 30 minutes

Implement proper error handling and write unit tests.

Requirements:

1. Global Exception Handler:

   • Handle validation errors
   • Handle database errors
   • Return proper HTTP status codes

2. Custom Exceptions:

   • NotFoundException - 404 responses
   • UnauthorizedException - 401 responses
   • ForbiddenException - 403 responses

3. Unit Tests:

   • Test all CRUD operations
   • Test authentication flow
   • Use pytest fixtures for database setup

Deliverables:

• utils/exceptions.py - Custom exception classes
• tests/ directory with all test files
• Test coverage report

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Test Scenarios

Complete these test scenarios to demonstrate system functionality:

Scenario 1: User Registration & Authentication

1. Register new user with email and password
2. Login with credentials
3. Access protected endpoint with JWT token
4. Verify 401 response without token

Scenario 2: Ticket Lifecycle

1. Create a support ticket
2. List all user's tickets
3. Update ticket status to "InProgress"
4. Resolve the ticket
5. Verify status transitions

Scenario 3: Booking with Validation

1. Attempt to book with past time → 400 error
2. Create valid booking for future time
3. Update booking time
4. Cancel the booking
5. Verify cannot update canceled booking

Scenario 4: Chat with AI (if integrated)

1. Start new conversation
2. Send IT support query → AI responds
3. Request to create ticket → HITL interrupt
4. Confirm action → Ticket created in database
5. Verify ticket exists via Ticket API

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Questions to Answer

Include written responses to these questions in ANSWERS.md:

1. Database Design: Why did you choose this table structure? What are the trade-offs of using foreign keys for user_id?

2. Authentication: Explain the JWT token flow. What are the security considerations for token storage on the client side?

3. API Design: Why use UUIDs for ticket_id/booking_id instead of auto-increment IDs? What are the pros and cons?

4. Error Handling: How would you implement rate limiting for the API? What HTTP status code would you return?

5. Integration: Describe how you would deploy this API with the AI Core in a production environment. Consider: containerization, scaling, monitoring.

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Submission Requirements

Directory Structure

fpt-customer-chatbot-api/
├── routers/
│   ├── auth.py
│   ├── users.py
│   ├── tickets.py
│   ├── bookings.py
│   └── chat.py
├── models/
│   ├── user.py
│   ├── ticket.py
│   ├── booking.py
│   └── conversation.py
├── schemas/
│   ├── user.py
│   ├── ticket.py
│   ├── booking.py
│   └── chat.py
├── crud/
│   ├── users.py
│   ├── tickets.py
│   └── bookings.py
├── services/
│   ├── chat_service.py
│   └── ai_adapter.py
├── utils/
│   ├── security.py
│   └── exceptions.py
├── tests/
│   ├── test_auth.py
│   ├── test_tickets.py
│   ├── test_bookings.py
│   └── conftest.py
├── main.py
├── database.py
├── config.py
├── dependencies.py
├── requirements.txt
├── README.md
└── ANSWERS.md

Required Deliverables

• Complete source code following directory structure
• README.md with:
  • Setup instructions (environment, dependencies)
  • API documentation (or link to Swagger UI)
  • Notes on AI Core integration
• ANSWERS.md with written responses to all 5 questions
• requirements.txt with all dependencies
• Demo video or screenshots showing:
  • User registration and login flow
  • Ticket CRUD operations
  • Booking CRUD operations
  • Chat with AI (if integrated)

Submission Checklist

• All code runs without errors
• Database models properly defined
• Authentication flow works
• All CRUD endpoints functional
• Input validation working
• Error handling implemented
• Unit tests passing
• Documentation complete

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Evaluation Criteria

Criteria	Points	Excellent (100%)	Good (75%)	Needs Improvement (50%)
Project Setup & Models (Task 1)	15	Perfect structure, all models, proper schemas	Working but minor issues in structure	Basic setup, missing some models
Authentication (Task 2)	20	Complete auth flow with proper security	Auth works but minor security gaps	Basic auth without token validation
Ticket API (Task 3)	20	Full CRUD with validation and tests	Most operations work, some validation missing	Only 1-2 operations functional
Booking API (Task 4)	20	Full CRUD with time validation and tests	Most operations work, time validation issues	Only 1-2 operations functional
Chat API & Integration (Task 5)	15	Full integration with AI Core working	Chat works with mock responses	Basic endpoint without proper integration
Error Handling & Testing (Task 6)	10	Comprehensive error handling and 80%+ coverage	Basic error handling and some tests	Minimal error handling, few tests
Total	100

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Hints

:::tip Project Structure

• Use APIRouter for organizing endpoints by resource
• Use Pydantic's BaseModel for all request/response schemas
• Keep database models separate from Pydantic schemas :::

:::tip Authentication

• Use passlib with bcrypt for password hashing
• Use python-jose for JWT token creation/verification
• Store secret key in environment variables :::

:::tip Database

• Use Depends(get_db) for database session injection
• Consider using AsyncSession for better performance
• Use relationship() for foreign key relationships :::

:::tip Testing

• Use TestClient from FastAPI for endpoint testing
• Create a separate test database
• Use pytest.fixture for test setup/teardown :::

:::tip AI Integration

• Create an adapter layer to abstract AI Core
• Handle async operations properly
• Implement proper error handling for AI failures :::

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References

• FastAPI Documentation
• SQLAlchemy 2.0 Documentation
• Pydantic V2 Documentation
• FastAPI Security
• pytest Documentation
• JWT Token Best Practices