Add PATCH /users/{userId} route with Kysely database integration

[Copilot]

Overview

Implements the PATCH /users/{userId} endpoint for updating user information in the Users table, addressing issue requirements for partial updates with database integration.

Changes Made

1. Users Lambda Handler

Created a new Lambda handler at apps/backend/lambdas/users/ using the lambda-cli scaffolding tool. This provides:

• Full TypeScript support with proper typing
• Health check endpoint at /health
• Local development server with hot-reload support
• OpenAPI specification for API documentation

2. Database Integration with Kysely

• Installed and configured Kysely ORM with better-sqlite3 driver
• Created database.ts with type-safe database schema definitions
• Implemented helper functions to convert between SQLite integers and JavaScript booleans
• Database connection management with environment variable support

3. Database Schema Updates

Extended the existing user table with two new columns:

• name (VARCHAR, nullable) - stores user's display name
• isAdmin (INTEGER, default 0) - stores admin status (0 = false, 1 = true)

Migration SQL is documented in apps/backend/lambdas/users/migration.sql for reproducibility.

4. PATCH /users/{userId} Implementation

Implemented comprehensive partial update logic:

// Update both fields
PATCH /users/1
{ "name": "John Doe", "isAdmin": true }

// Update only name (partial update)
PATCH /users/1
{ "name": "Jane Smith" }

// Update only isAdmin (partial update)
PATCH /users/1
{ "isAdmin": false }

Features:

• ✅ Partial updates - any combination of fields
• ✅ Type validation - ensures name is string, isAdmin is boolean
• ✅ ID validation - validates userId is a valid integer
• ✅ Existence check - returns 404 for non-existent users
• ✅ Required fields - at least one field must be provided
• ✅ Returns updated user data with proper boolean conversion

Response Example:

{
  "id": 1,
  "email": "user@example.com",
  "name": "John Doe",
  "isAdmin": true
}

5. Comprehensive Testing

Added 11 Jest test cases covering all scenarios:

• Successful updates (name only, isAdmin only, both fields)
• Partial update behavior validation
• Error handling (404 for missing users, 400 for invalid inputs)
• Type validation for all fields
• Edge cases (empty body, invalid ID format)

All tests passing: ✅ 11/11

6. Documentation

• Created comprehensive README.md with API documentation
• Documented setup instructions and local development workflow
• Added example curl commands for testing
• Documented database schema and migration steps

API Documentation

Endpoint

PATCH /users/{userId}

Request

curl -X PATCH http://localhost:3000/users/users/1 \
  -H "Content-Type: application/json" \
  -d '{"name": "John Doe", "isAdmin": true}'

Responses

• 200 OK - User updated successfully with user object
• 400 Bad Request - Invalid userId format, invalid field types, or no fields provided
• 404 Not Found - User does not exist
• 500 Internal Server Error - Server error

Testing

Manual testing verified with local dev server and automated tests confirm all acceptance criteria:

• ✅ Route updates user information correctly
• ✅ Returns 200 with updated user data
• ✅ Jest tests confirm updates, invalid IDs, and invalid fields
• ✅ Partial updates work as expected

Technical Details

• Framework: AWS Lambda with TypeScript
• Database: SQLite with Kysely ORM
• Testing: Jest with ts-jest
• Build: TypeScript compiler
• Local Dev: Custom dev-server with hot-reload

Files Changed

• Created apps/backend/lambdas/users/ directory with complete Lambda handler
• Updated db.sqlite with schema changes
• Added migration script, tests, and documentation

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Users] Add Update User Route (PATCH /users/{userId})</issue_title>
<issue_description>## User Story
As a user I want to update user information in the Users table.

Description

• Add the PATCH /users/{userId} route to the users Lambda using:
  node tools/lambda-cli.js add-route users PATCH /users/{userId} --body name:string,isAdmin:boolean
• Implement partial update logic using Kysely (db.updateTable('users').set({ name, isAdmin }).where('userID', '=', userId)).
• Test using Swagger and Jest.

Acceptance Criteria

• Route updates user information correctly.
• Swagger returns 200 with updated user data.
• Jest tests confirm updates, invalid IDs, and invalid fields.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #51

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