cadwyn_fastapi_versioned_api_with_schema_migration.py

1from datetime import date
2from fastapi import FastAPI
3from pydantic import Field
4from cadwyn import Cadwyn, Version, VersionBundle, schema
5from cadwyn.structure import RequestPatch, convert_request_to_next_version_for
6
7# 1. Define your schemas using cadwyn.schema.BaseModel
8class User(schema.BaseModel):
9    id: int
10    name: str
11
12# 2. Define your application
13app = FastAPI()
14
15@app.get("/users/{user_id}", response_model=User)
16async def get_user(user_id: int):
17    return {"id": user_id, "name": "John Doe"}
18
19# 3. Define version changes (e.g., renaming a field)
20class UserChange(VersionBundle):
21    @convert_request_to_next_version_for(User)
22    def rename_name_to_full_name(cls, request: RequestPatch):
23        request.data["full_name"] = request.data.pop("name")
24
25# 4. Define your version history
26versions = VersionBundle(
27    Version(date(2023, 1, 1), UserChange),
28    Version(date(2022, 1, 1)),
29)
30
31# 5. Initialize Cadwyn
32cadwyn = Cadwyn(app, versions=versions)
33app = cadwyn.app