RESTpy 0.7.1

Werkzeug extensions for building RESTful services.

Werkzeug utilities for building RESTful services.

What is RESTpy?

RESTpy is a small set of utilities built on Werkzeug that make it a little easier to roll out a RESTful web service. This project defines very few unique features outside of Werkzeug itself. Think of it like flask but with even less features.

Simple Usage Example

from restpy.api import Application
from restpy.api import Endpoint

from werkzeug.routing import Map
from werkzeug.routing import Rule
from werkzeug.wrappers import Response


# Endpoints define HTTP verb methods to handle requests.
class IndexEndpoint(Endpoint):

    def get(self, request):
        return Response("get")

    def post(self, request):
        return Response("post")

    def put(self, request):
        return Response("put")

    def delete(self, request):
        return Response("delete")

# URL mappings are normal Werkzeug routing Maps.
urls = Map([
    Rule("/", endpoint=IndexEndpoint)
])

# This object can be exposed to any WSGI server.
application = Application(urls)

Request/Response Hooks

RESTpy, in addition to supporting any standard WSGI middleware, supports the registration of global request and response hooks. Request hooks are any Python callable which accepts the current request as a first argument. Response hooks, likewise, accept the request and response as arguments. These can be used to inject generic functionality, like authentication, without writing your own middlewares.

import logging
from werkzueg.exceptions import Unauthorized

LOG = logging.getLogger(__name__)


def authenticate(request):
    """A hook which checks for the secret key."""
    if request.headers.get('Secrete-Token', None) != 42:

        raise Unauthorized()


def log_complete(request, response):
    """Log a message after every request."""
    LOG.debug('Request complete!')

application = Application(
    urls,
    before=(authenticate,),
    after=(log_complete,)
)

The ‘before’ and ‘after’ keyword arguments will accept any iterable of hooks. These hooks will be executed on each request.

Thread-Local Storage

Sharing data between middlewares, hooks, and endpoints can be difficult in multi-threaded, or green-threaded, environments. To assist, this package makes it easy to use the Werkzueg local objects to share data globally within a thread.

import uuid

from restpy.api import Application
from restpy.api import ContextClearMiddleware
from restpy.api import Endpoint
from restpy import context

from werkzeug.routing import Map
from werkzeug.routing import Rule
from werkzeug.wrappers import Response

class ThreadedEndpoint(Endpoint):

    def get(self, request):
        return Response(context.storage.unique_value)

def unique_value(request):
    """Set a random to the context storage."""
    context.storage.unique_value = (uuid.uuid4())

urls = Map([
    Rule("/", endpoint=ThreadedEndpoint)
])

# Set the thread context to clear after each request.
application = ContextClearMiddleware(
    Application(urls, before=(unique_value,))
)

The above example will generate a unique value for each request and return it in a GET request. If the WSGI application is run in a multi-threaded environment, using eventlet or gevent for example, the value will be unique to the thread which is executing. The ContextClearMiddleware helps ensure that stale data doesn’t stick around after a thread is complete.

Unique Request ID’s

Bundled with this project are a middleware and request hook which work together to provide a UUID for each request that hits an application. These helpers make use of the context storage to allow for easy logging of the request id as well.

import logging

from restpy.api import Application
from restpy.api import ContextClearMiddleware
from restpy.api import Endpoint
from restpy.api import RequestLogger
from restpy.api import unique_request
from restpy.api import UniqueEnvironMiddleware

from werkzeug.routing import Map
from werkzeug.routing import Rule
from werkzeug.wrappers import Response

class UniqueEndpoint(Endpoint):

    def get(self, request):
        return Response(request.uuid)

urls = Map([
    Rule("/", endpoint=UniqueEndpoint)
])

# Set the thread context to clear after each request.
application = ContextClearMiddleware(
    UniqueEnvironMiddleware(
        Application(urls, before=(unique_request))
    )
)

logging.basicConfig(
    format='%(levelname)s:%(request_id)s:%(message)s',
    level=logging.DEBUG,
)
logging.setLoggerClass(RequestLogger)

The above example configures the application to generate a new UUID for every request, store this uuid on the request object and context storage, and configure logging to include the unique request id in every log message.

License

This project is released under the same BSD license as Werkzeug:

Copyright (c) 2013 by Kevin Conway

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * The names of the contributors may not be used to endorse or
      promote products derived from this software without specific
      prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Contributor’s Agreement

All contributions to this project are protected by the contributors agreement detailed in the CONTRIBUTING file. All contributors should read the file before contributing, but as a summary:

You give us the rights to distribute your code and we promise to maintain
an open source release of anything you contribute.