feat: added facets endpoint #737

[MillenniumFalconMechanic]

Ticket

Closes #737.

Changes

This pull request introduces a minimal FastAPI backend for the Findable project, providing a stubbed query-to-facets API endpoint for early experimentation. It includes the initial backend structure, request/response models, a controller, a service with a hard-coded response, and developer documentation. Additionally, it adds Python formatting checks and required dependencies.

Backend implementation:

• Added a FastAPI application in backend/main.py that registers a /api/v0/facets endpoint via the facets_controller router. [1] [2]
• Implemented request (FacetsRequest) and response (FacetsResponse, FacetSelection, SelectedValue) models using Pydantic for the facets endpoint. [1] [2]
• Created a stubbed service (compute_facets_from_query) that returns a hard-coded facets response for proof-of-concept purposes.

Developer experience and documentation:

• Added backend/README.md with setup instructions, endpoint details, and example usage for running and formatting the backend.
• Introduced Python dependencies (fastapi, uvicorn, pydantic, black) in backend/requirements.txt.
• Updated .husky/pre-commit to check Python code formatting with Black before commits.

[Copilot]

Pull request overview

This PR introduces a minimal FastAPI backend to support early experimentation with a query-to-facets API endpoint. The implementation provides a foundation for LLM-backed intent parsing with a stubbed service layer that returns hard-coded responses for proof-of-concept purposes.

Key changes:

• Added a FastAPI application with POST /api/v0/facets endpoint for converting natural language queries to facet selections
• Implemented Pydantic models for request/response validation with multi-level nested structures
• Integrated Python code formatting with Black into the pre-commit workflow

Reviewed changes

Copilot reviewed 8 out of 12 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
backend/main.py	FastAPI application entry point that registers the facets router
backend/controllers/facets_controller.py	API router defining the POST endpoint and delegating to the service layer
backend/controllers/models.py	Pydantic request model for the facets endpoint
backend/services/facets_service.py	Service function returning stubbed facet data for PoC
backend/services/models.py	Pydantic response models (FacetsResponse, FacetSelection, SelectedValue)
backend/requirements.txt	Python dependencies including FastAPI, Uvicorn, Pydantic, and Black
backend/README.md	Developer documentation for setup, running, and testing the backend
.husky/pre-commit	Added Black formatter check to pre-commit hooks
.gitignore	Added Python-specific ignore patterns (.venv, pycache, *.pyc)

Comments suppressed due to low confidence (2)

backend/controllers/facets_controller.py:2

• Import of 'BaseModel' is not used.

from pydantic import BaseModel

backend/services/facets_service.py:3

• Import of 'BaseModel' is not used.

from pydantic import BaseModel

[Copilot]

Pull request overview

Copilot reviewed 8 out of 12 changed files in this pull request and generated 4 comments.

Comments suppressed due to low confidence (1)

backend/controllers/facets_controller.py:2

• Import of 'BaseModel' is not used.

from pydantic import BaseModel

[Copilot]

Pull request overview

Copilot reviewed 8 out of 12 changed files in this pull request and generated 2 comments.