REST APIs with FastAPI

from fastapi import FastAPI, HTTPException
from fastapi.testclient import TestClient
from pydantic import BaseModel
 
app = FastAPI(title="Documents API", version="1.0")
 
class DocIn(BaseModel):
    title: str
    text: str
 
class Doc(DocIn):
    id: int
 
DB: dict[int, Doc] = {}
 
@app.post("/documents", status_code=201, response_model=Doc)       # create
def create(doc: DocIn):
    new = Doc(id=len(DB) + 1, **doc.model_dump())
    DB[new.id] = new
    return new
 
@app.get("/documents", response_model=list[Doc])                    # list
def list_docs():
    return list(DB.values())
 
@app.get("/documents/{doc_id}", response_model=Doc)                 # read one
def read(doc_id: int):
    if doc_id not in DB:
        raise HTTPException(404, "document not found")
    return DB[doc_id]
 
@app.delete("/documents/{doc_id}", status_code=204)                 # delete
def delete(doc_id: int):
    DB.pop(doc_id, None)
 
c = TestClient(app)
print(c.post("/documents", json={"title": "Leave", "text": "25 days"}).status_code, "created")
print(c.post("/documents", json={"title": "Expenses", "text": "Meals 40/day"}).json())
print(c.get("/documents").status_code, [d["title"] for d in c.get("/documents").json()])
print(c.delete("/documents/1").status_code, "deleted")
print(c.get("/documents/1").status_code, c.get("/documents/1").json())
spec = c.get("/openapi.json").json()                                # generated automatically
print("OpenAPI paths:", {p: sorted(ops) for p, ops in spec["paths"].items()})

201 created
{'title': 'Expenses', 'text': 'Meals 40/day', 'id': 2}
200 ['Leave', 'Expenses']
204 deleted
404 {'detail': 'document not found'}
OpenAPI paths: {'/documents': ['get', 'post'], '/documents/{doc_id}': ['delete', 'get']}