cadwyn_fastapi_versioned_api_schema_migration_quickstart.py

1from datetime import date
2from fastapi import FastAPI
3from pydantic import BaseModel, Field
4from cadwyn import Cadwyn, Version, VersionBundle, migrate_response_body_by_path
5
6# 1. Define your schemas
7class UserCreate(BaseModel):
8    first_name: str
9    last_name: str
10
11class UserRead(BaseModel):
12    id: int
13    full_name: str
14
15# 2. Define your application
16app = FastAPI()
17
18@app.post("/users", response_model=UserRead)
19async def create_user(user: UserCreate):
20    return {"id": 1, "full_name": f"{user.first_name} {user.last_name}"}
21
22# 3. Define version changes
23class ChangeFullNameToFirstAndLastName(VersionBundle):
24    def __init__(self):
25        super().__init__(
26            Version(
27                date(2023, 1, 1),
28                migrate_response_body_by_path(
29                    "POST /users",
30                    lambda body: {
31                        "id": body["id"],
32                        "full_name": f"{body['first_name']} {body['last_name']}",
33                    },
34                ),
35            ),
36        )
37
38# 4. Initialize Cadwyn
39cadwyn = Cadwyn(app, versions=ChangeFullNameToFirstAndLastName())
40
41# This will generate versioned routes based on your definitions
42cadwyn.generate_versioned_routers()