What's new in Bocadillo 0.16

June 1st, 2019 · Florimond Manca

Bocadillo 0.16 has been released! Learn what's in it for you: routers, plugin registration, unified middleware, and more.

If you have any questions or feedback about this release, feel free to get in touch!


Routers are a new and powerful way of splitting applications into more manageable chunks.

For example, you can create an authentication router…

# myproject/routers/auth.py
from bocadillo import Router

router = Router()

@router.route("/login", methods=["post"])
async def login(req, res):

@router.route("/logout", methods=["post"])
async def logout(req, res):

…and include it into the main app later on:

# myproject/app.py
from bocadillo import App
from .routers import auth

app = App()

To learn more, read the new Routers guide.

Plugin registration

The plugin system built into Bocadillo allows to build settings-based features. In fact, many built-in Bocadillo features are implemented using plugins. Yet, there was no easy way to register custom plugins… Until now!

You can use the new PLUGINS setting to register your own or third-party Bocadillo plugins into your application.

As a concrete example, let's write a plugin which registers the auth router we wrote earlier:

# myproject/plugins.py
from .routers import auth

def use_auth(app):

(Note that plugins do not need the @plugin decorator anymore. This decorator is now deprecated and will be removed in the next minor release.)

We can now add the use_auth plugin to the list of PLUGINS:

# myproject/settings.py
from .plugins import use_auth

PLUGINS = [use_auth]

This may seem like an extra level of indirection, but it's actually a cleaner way to add functionality to an application.

For example, we can use conditional registration to apply the plugin only if the ENABLE_AUTH environment variable is set:

# myproject/settings.py
from starlette.config import Config
from .plugins import use_auth

config = Config(".env")

    {use_auth: config("ENABLE_AUTH", cast=bool, default=True)}

You can now control whether auth routes are exposed via environment variables!

We hope this settings-based plugin registration API will enable Bocadillo users to share and reuse plugins more easily.

To learn more about this, read the updated Plugins guide.

Unified middleware

When registering middleware, there was previously a distinction between HTTP middleware (using app.add_middleware()) and ASGI middleware (using app.add_asgi_middleware()).

Thanks to an internal refactoring, all middleware can now be registered via app.add_middleware(). As a result, app.add_asgi_middleware() is now deprecated.

Besides, exceptions raised in ASGI middleware are now processed by error handlers. For example, you can raise HTTPError(400) and Bocadillo will return a 400 Bad Request response like it would in views or HTTP middleware.

We think all this will help make working with middleware more enjoyable and straight-forward.

To learn more, read the updated Middleware guide.


Trailing slash redirects

If the requested URL path does not end with a trailing slash, e.g. /items, Bocadillo now appends one and redirects clients to the new URL, e.g. /items/.

This prevents clients from obtaining a confusing 404 Not Found error simply because they forgot to add a trailing slash.

If necessary, you can opt out using the REDIRECT_TRAILING_SLASH setting.

To learn more, read About trailing slashes.

HTTP methods

From 0.16, HTTP methods on function-based views can be specified more simply using the methods= argument to @route():

@app.route("/items", methods=["post"])
async def create_item(req, res):

Previously, you had to use the (now deprecated) @view() decorator:

from bocadillo import view

async def create_item(req, res):

See also: HTTP methods.


The ALL_HTTP_METHODS constant (from bocadillo.constants) now contains HTTP methods in lowercase, instead of uppercase.


res.media has deprecated since 0.14, and it has now been removed. Please use res.json instead. For more information, see Sending content.