FastAPI

• It's a web framework for building APIs with Python
• Fullstack template: https://github.com/fastapi/full-stack-fastapi-template

Installation

pip install "fastapi[standard]"

Dependencies

• fastapi
• starlette for the web parts (WebSockets, CORS, Cookie Sessions, etc)
  • httpx: TestClient
  • jinja2: default template configuration
  • python-multipart: support parsing from request.form()
• pydantic for the schemas, validation, serialization, etc
  • email-validator
• fastapi-cli
• uvicorn: http server that loads and serves the app

Project structure

.
├── app                  # "app" is a Python package
│   ├── __init__.py      # this file makes "app" a "Python package"
│   ├── main.py          # "main" module, e.g. import app.main
│   ├── deps.py          # "dependencies" module, e.g. import app.dependencies
│   └── routers          # "routers" is a "Python subpackage"
│   │   ├── __init__.py  # makes "routers" a "Python subpackage"
│   │   ├── items.py     # "items" submodule, e.g. import app.routers.items
│   │   └── users.py     # "users" submodule, e.g. import app.routers.users
│   └── internal         # "internal" is a "Python subpackage"
│       ├── __init__.py  # makes "internal" a "Python subpackage"
│       └── admin.py     # "admin" submodule, e.g. import app.internal.admin

ASGI Server (Asynchronous Server Gateway Interface)

• http://localhost:8000/
• http://localhost:8000/docs: Swagger UI
• http://localhost:8000/openapi.json: OpenAPI contract
• http://localhost:8000/redoc: ReDoc

fastapi dev main.py # runs with unicorn by default

• Uvicorn: a high performance ASGI server (the default used by fastapi)
• Hypercorn: an ASGI server compatible with HTTP/2 and Trio among other features.
• Daphne: the ASGI server built for Django Channels.
• Granian: A Rust HTTP server for Python applications.

• NGINX Unit: NGINX Unit is a lightweight and versatile web application runtime.

• Other web frameworks like Flask and Django use WDGI (Web Server Gateway Interface)

Debugging

You can run the uvicorn ASGI server directly from the Python file:

import uvicorn

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

And run it as a python module:

# your cwd needs to be the parent directory of the demo package
python -m app.main # package "app", module "main"

Generating SDK

• You can generate Typescript SDK based on your OpenAPI specification using Hey API

# Generate the typescript SDK to ./src/client
npx @hey-api/openapi-ts -i http://localhost:8000/openapi.json -o src/client

// "Default" is the name of the tag used (when not specified) in FastAPI
import { DefaultService } from "./client"

async function main() {
  const response = await DefaultService.createItemPost({
    name: "Plumbus",
    Price: 5,
  });
  response.message
}