Question

I want API support for:

GET /api/spam/{id}

POST /api/spam
body: {'name': 'green spam'}

I would normally route to a Handler by:

webapp.WSGIApplication([r'/api/spam/(.*)', APISpam])

class APISpam(RequestHandler):
    def get(self, id):
       # do stuff

    def post(self):
       # do stuff

But the post fails because it’s expecting a second argument. What is the best design pattern to accommodate RESTful url patterns to Handlers for each type of resource?

UPDATE:

It is being pointed out that the uri examples above represent a collection (/spam) and an element (/spam/{id}). That is not my intention. Both uri examples are for the element spam, one is to GET a specific spam, and the other is to POST a new spam. The reason I am not using /spam/{id} for the POST is because I am creating a new spam, and therefore do not have an id.

Answer 1

Normally you’d simply make them separate handlers: As Sebastian points out, they’re different resources – the collection itself, vs one element of the collection.

If you must use the same handler, though, you can supply a default argument:

class APISpam(RequestHandler):
  def get(self, id=None):
    # do stuff

  def post(self, id=None):
    # do stuff

application = webapp.WSGIApplication([r'/api/spam(?:/(.*))?'])

Both get and post handlers will be callable without an ID, though – in all likelihood, you really should use separate handlers.