BlackSheep

BlackSheep is an asynchronous web framework to build event based web applications with Python. It is inspired by Flask, ASP.NET Core, and the work by Yury Selivanov.

BlackSheep is the project name of the web framework in Neoteroi. With the second version of the framework, the Python package is renamed from blacksheep to neoteroi-web.

pip install neoteroi-web

The first version of the web framework is available as blacksheep and is not going to be willingly modified in non-backward compatible ways (it is stable). neoteroi-web is currently alpha and still subject to change.

from datetime import datetime

from neoteroi.web import Application


app = Application()

@app.route("/")
async def home():
    return f"Hello, World! {datetime.utcnow().isoformat()}"

Getting started

The documentation offers getting started tutorials:

• Getting started: basics
• Getting started: the MVC project template

These project templates can be used to start new applications faster:

• MVC project template
• Empty project template

Requirements

Python: any version listed in the project's classifiers. The current list is:

BlackSheep belongs to the category of ASGI web frameworks, so it requires an ASGI HTTP server to run, such as uvicorn, or hypercorn. For example, to use it with uvicorn:

$ pip install uvicorn

To run an application like in the example above, use the methods provided by the ASGI HTTP Server:

# if the web app is defined in a file `server.py`

$ uvicorn server:app

To run for production, refer to the documentation of the chosen ASGI server (i.e. for uvicorn).

Automatic bindings and dependency injection

BlackSheep supports automatic binding of values for request handlers, by type annotation or by conventions. See more here.

from dataclasses import dataclass

from neoteroi.web import Application, FromJSON, FromQuery


app = Application()


@dataclass
class CreateCatInput:
    name: str


@app.router.post("/api/cats")
async def example(data: FromJSON[CreateCatInput]):
    # in this example, data is bound automatically reading the JSON
    # payload and creating an instance of `CreateCatInput`
    ...


@app.router.get("/:culture_code/:area")
async def home(culture_code, area):
    # in this example, both parameters are obtained from routes with
    # matching names
    return f"Request for: {culture_code} {area}"


@app.router.get("/api/products")
def get_products(
    page: int = 1,
    size: int = 30,
    search: str = "",
):
    # this example illustrates support for implicit query parameters with
    # default values
    # since the source of page, size, and search is not specified and no
    # route parameter matches their name, they are obtained from query string
    ...


@app.router.get("/api/products2")
def get_products2(
    page: FromQuery[int] = FromQuery(1),
    size: FromQuery[int] = FromQuery(30),
    search: FromQuery[str] = FromQuery(""),
):
    # this example illustrates support for explicit query parameters with
    # default values
    # in this case, parameters are explicitly read from query string
    ...

It also supports dependency injection, a feature that provides a consistent and clean way to use dependencies in request handlers.

Generation of OpenAPI Documentation

Generation of OpenAPI Documentation.

Strategies to handle authentication and authorization

BlackSheep implements strategies to handle authentication and authorization. These features are documented here:

• Authentication
• Authorization

app.use_authentication()\
    .add(ExampleAuthenticationHandler())


app.use_authorization()\
    .add(AdminsPolicy())


@auth("admin")
@app.router.get("/")
async def only_for_admins():
    ...


@auth()
@app.router.get("/")
async def only_for_authenticated_users():
    ...

The framework includes:

• Built-in support for OpenID Connect authentication
• Built-in support for JWT Bearer authentication

Meaning that it is extremely easy to integrate with services such as:

• Auth0
• Azure Active Directory
• Azure Active Directory B2C
• Okta

Refer to the documentation for more details and examples.

Web framework features

• ASGI compatibility
• Routing
• Request handlers can be defined as functions, or class methods
• Middlewares
• WebSocket
• Built-in support for dependency injection
• Support for automatic binding of route and query parameters to request handlers methods calls
• Strategy to handle exceptions
• Strategy to handle authentication and authorization
• Built-in support for OpenID Connect authentication using OIDC discovery
• Built-in support for JWT Bearer authentication using OIDC discovery and other sources of JWKS
• Handlers normalization
• Serving static files
• Integration with Jinja2
• Support for serving SPAs that use HTML5 History API for client side routing
• Support for automatic generation of OpenAPI Documentation
• Strategy to handle CORS settings
• Sessions
• Support for automatic binding of dataclasses and pydantic models to handle the request body payload expected by request handlers
• TestClient class to simplify testing of applications
• Anti Forgery validation to protect against Cross-Site Request Forgery (XSRF/CSRF) attacks

Client features

BlackSheep includes an HTTP Client.

Example:

import asyncio
from neoteroi.web.client import ClientSession


async def client_example(loop):
    async with ClientSession() as client:
        response = await client.get("https://docs.python.org/3/")

        assert response is not None
        text = await response.text()
        print(text)


loop = asyncio.get_event_loop()
loop.run_until_complete(client_example(loop))

Supported platforms and runtimes

• Python: all versions included in the build matrix
• Ubuntu
• Windows 10
• macOS

Documentation

Please refer to the documentation website.

Communication

Community in Gitter.