Classes and Decorators to use FastAPI with Class based routing

---

Source Code: https://github.com/yezz123/fastapi-class

Install the project: pip install fastapi-class

---

As you create more complex FastAPI applications, you may find yourself frequently repeating the same dependencies in multiple related endpoints.

A common question people have as they become more comfortable with FastAPI is how they can reduce the number of times they have to copy/paste the same dependency into related routes.

fastapi_class provides a class-based view decorator @View to help reduce the amount of boilerplate necessary when developing related routes.

Highly inspired by Fastapi-utils, Thanks to @dmontagu for the great work.

• Example:

from fastapi import FastAPI, Query
from pydantic import BaseModel
from fastapi_class import View

app = FastAPI()

class ItemModel(BaseModel):
    id: int
    name: str
    description: str = None

@View(app)
class ItemView:
    async def post(self, item: ItemModel):
        return item

    async def get(self, item_id: int = Query(..., gt=0)):
        return {"item_id": item_id}

Response model 📦

Exception in list need to be either function that return fastapi.HTTPException itself. In case of a function it is required to have all of it's arguments to be optional.

from fastapi import FastAPI, HTTPException, status
from fastapi.responses import PlainTextResponse
from pydantic import BaseModel

from fastapi_class import View

app = FastAPI()

NOT_AUTHORIZED = HTTPException(401, "Not authorized.")
NOT_ALLOWED = HTTPException(405, "Method not allowed.")
NOT_FOUND = lambda item_id="item_id": HTTPException(404, f"Item with {item_id} not found.")

class ItemResponse(BaseModel):
    field: str | None = None

@View(app)
class MyView:
    exceptions = {
        "__all__": [NOT_AUTHORIZED],
        "put": [NOT_ALLOWED, NOT_FOUND]
    }

    RESPONSE_MODEL = {
        "put": ItemResponse
    }

    RESPONSE_CLASS = {
        "delete": PlainTextResponse
    }

    async def get(self):
        ...

    async def put(self):
        ...

    async def delete(self):
        ...

Customized Endpoints

from fastapi import FastAPI, HTTPException
from fastapi.responses import PlainTextResponse
from pydantic import BaseModel

from fastapi_class import View, endpoint

app = FastAPI()

NOT_AUTHORIZED = HTTPException(401, "Not authorized.")
NOT_ALLOWED = HTTPException(405, "Method not allowed.")
NOT_FOUND = lambda item_id="item_id": HTTPException(404, f"Item with {item_id} not found.")
EXCEPTION = HTTPException(400, "Example.")

class UserResponse(BaseModel):
    field: str | None = None

@View(app)
class MyView:
    exceptions = {
        "__all__": [NOT_AUTHORIZED],
        "put": [NOT_ALLOWED, NOT_FOUND],
        "edit": [EXCEPTION]
    }

    RESPONSE_MODEL = {
        "put": UserResponse,
        "edit": UserResponse
    }

    RESPONSE_CLASS = {
        "delete": PlainTextResponse
    }

    async def get(self):
        ...

    async def put(self):
        ...

    async def delete(self):
        ...

    @endpoint(("PUT"), path="edit")
    async def edit(self):
        ...

Note: The edit() endpoint is decorated with the @endpoint(("PUT",), path="edit") decorator, which specifies that this endpoint should handle PUT requests to the /edit path, using @endpoint("PUT", path="edit") has the same effect

Development 🚧

Setup environment 📦

You should create a virtual environment and activate it:

python -m venv venv/

source venv/bin/activate

And then install the development dependencies:

Note: You should have uv installed, if not you can install it with:

pip install uv

Then you can install the dependencies with:

# Install dependencies
uv pip install -r requirements/all.txt

Run tests 🌝

You can run all the tests with:

bash scripts/test.sh

Format the code 🍂

Execute the following command to apply pre-commit formatting:

bash scripts/format.sh

Execute the following command to apply mypy type checking:

bash scripts/lint.sh

License

This project is licensed under the terms of the MIT license.