Routing

Goal

This snapshot advances Rivermouth Dispatch by teaching you to organize page routes with an APIRouter.

Every numbered folder is a complete app. Run this stage independently, then compare it with the previous folder.

Prerequisites

Use Python 3.11+, a terminal, and Docker for Postgres stages. You should recognize functions, modules, and HTTP verbs.

Port 8001 must be free. Copy .env.example before starting database stages.

• Python 3 and pip/venv
• A code editor and terminal
• Docker from part 4 onward

Concepts

Routers group related endpoints and can be included on the main app. Route order and methods both matter.

Keep request handling thin: routes accept input, services/models enforce rules, and Jinja templates escape output by default.

Walkthrough

Move home and about handlers into a router, include it from the app, and add a health endpoint.

Read the example, then open the matching snapshot. The repository includes the surrounding setup and error handling.

router = APIRouter()
router.get("/")(home)
app.include_router(router)

Run and verify

Enter 02-Routing, create a virtualenv, install requirements, copy .env.example when present, and start Uvicorn on port 8001.

Open http://127.0.0.1:8001. Watch the terminal for validation and database errors.

git clone https://github.com/michaeldunga1/fcc-fastapi-blog.git
cd fcc-fastapi-blog/02-Routing
python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
cp .env.example .env
uvicorn main:app --reload --port 8001

Troubleshooting

A missing include_router call leaves routes undefined. Check both path and HTTP method.

Import errors usually mean the virtualenv is inactive or you installed packages in another snapshot. For Postgres failures, confirm Docker and the rivermouth_NN database name.

• Read the first error first
• Restart after environment changes
• Never commit .env or .venv

Try this

Add a /contact plain-text route.

Test a happy path and one invalid or unauthorized request.

• Make one small change
• Test it in the browser
• Compare with the next snapshot only after it works