142 lines
4.4 KiB
Python
142 lines
4.4 KiB
Python
import json
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import logging
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from wsgiref import simple_server
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import falcon
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class StorageEngine:
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pass
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class StorageError(Exception):
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@staticmethod
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def handle(ex, req, resp, params):
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description = ('Sorry, couldn\'t write your thing to the '
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'database. It worked on my box.')
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raise falcon.HTTPError(falcon.HTTP_725,
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'Database Error',
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description)
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class Proxy(object):
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def forward(self, req):
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return falcon.HTTP_503
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class SinkAdapter(object):
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def __init__(self):
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self._proxy = Proxy()
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def __call__(self, req, resp, **kwargs):
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resp.status = self._proxy.forward(req)
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self.kwargs = kwargs
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def token_is_valid(token, user_id):
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return True # Suuuuuure it's valid...
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def auth(req, resp, params):
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# Alternatively, use Talons or do this in WSGI middleware...
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token = req.get_header('X-Auth-Token')
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if token is None:
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description = ('Please provide an auth token '
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'as part of the request.')
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raise falcon.HTTPUnauthorized('Auth token required',
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description,
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href='http://docs.example.com/auth')
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if not token_is_valid(token, params['user_id']):
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description = ('The provided auth token is not valid. '
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'Please request a new token and try again.')
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raise falcon.HTTPUnauthorized('Authentication required',
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description,
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href='http://docs.example.com/auth',
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scheme='Token; UUID')
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def check_media_type(req, resp, params):
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if not req.client_accepts_json:
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raise falcon.HTTPUnsupportedMediaType(
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'This API only supports the JSON media type.',
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href='http://docs.examples.com/api/json')
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class ThingsResource:
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def __init__(self, db):
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self.db = db
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self.logger = logging.getLogger('thingsapp.' + __name__)
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def on_get(self, req, resp, user_id):
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marker = req.get_param('marker') or ''
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limit = req.get_param_as_int('limit') or 50
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try:
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result = self.db.get_things(marker, limit)
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except Exception as ex:
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self.logger.error(ex)
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description = ('Aliens have attacked our base! We will '
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'be back as soon as we fight them off. '
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'We appreciate your patience.')
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raise falcon.HTTPServiceUnavailable(
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'Service Outage',
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description,
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30)
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resp.set_header('X-Powered-By', 'Donuts')
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resp.status = falcon.HTTP_200
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resp.body = json.dumps(result)
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def on_post(self, req, resp, user_id):
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try:
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# req.stream corresponds to the WSGI wsgi.input environ variable,
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# and allows you to read bytes from the request body.
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#
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# json.load assumes the input stream is encoded at utf-8 if the
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# encoding is not specified explicitly.
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#
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# See also: PEP 3333
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thing = json.load(req.stream, 'utf-8')
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except ValueError:
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raise falcon.HTTPError(falcon.HTTP_753,
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'Malformed JSON',
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'Could not decode the request body. The '
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'JSON was incorrect.')
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proper_thing = self.db.add_thing(thing)
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resp.status = falcon.HTTP_201
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resp.location = '/%s/things/%s' % (user_id, proper_thing.id)
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# Configure your WSGI server to load "things.app" (app is a WSGI callable)
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app = falcon.API(before=[auth, check_media_type])
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db = StorageEngine()
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things = ThingsResource(db)
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app.add_route('/{user_id}/things', things)
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# If a responder ever raised an instance of StorageError, pass control to
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# the given handler.
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app.add_error_handler(StorageError, StorageError.handle)
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# Proxy some things to another service. This example shows how you might
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# send parts of an API off to a legacy system that hasn't been upgraded
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# yet, or perhaps is a single cluster that all datacenters have to share.
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sink = SinkAdapter()
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app.add_sink(sink, r'/v1/[charts|inventory]')
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# Useful for debugging problems in your API; works with pdb.set_trace()
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if __name__ == '__main__':
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httpd = simple_server.make_server('127.0.0.1', 8000, app)
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httpd.serve_forever()
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