serverwamp 0.1.0

An adapter for aiohttp, enabling a server to service WAMP calls and subscriptions over WebSockets.

serverwamp

Components that add Web Application Messaging Protocol features to WebSocket servers. With server_wamp, an aiohttp server can act as both a WAMP broker and dealer.

Example WAMP Microservice

from aiohttp import web
from server_wamp.adapters.aiohttp import WAMPApplication
from server_wamp.rpc import RPCRouteTableDef, RPCError

rpc_routes = RPCRouteTableDef()

@rpc_routes.route('myapp:getDoc')
async def get_document(document_id):
    record = await mydb.retrieve(document_id)
    return {'status': 'SUCCESS', 'document': record}

@rpc_routes.route('myapp:delDoc')
async def delete_document(document_id):
    succeeded = await mydb.delete(document_id)
    if succeeded:
        return {'status': 'SUCCESS'}
    else:
        raise RPCError('wamp.error.delete_failed', {'status': 'FAILURE'})


if __name__ == '__main__':
    wamp = WAMPApplication()
    wamp.add_rpc_routes(rpc_routes)

    app = web.Application()
    app.add_routes((web.get('/', wamp.handle),))
    web.run_app(app)

Compared to Traditional WAMP

Traditionally, WAMP clients connect to a WAMP router either to provide functionality or to use functionality provided by other clients. This library enables a server to respond to calls and subscriptions like a WAMP router would, but serve them in a custom way instead of routing them to other clients.

You might do this to provide Python-based web services over a WebSocket using a typical client and server model, while taking advantage of the structure the WAMP protocol provides.

In summary, this is not a WAMP router, but you could use it to build one if you wanted.

This library is good if…

• you like developing in micro-frameworks like Flask and aiohttp, but want to branch into serving over WebSockets.
• you want a structure for communicating over WebSockets, but want more request/response features than the socket.io protocol provides.
• you want to build a WAMP router.

It's not as useful if…

• you want to build a WAMP client
  • Consider Autobahn|Python instead.
• you want a WAMP router out of the box.
  • Consider Crossbar.io instead.

Known Deficiencies

• Project is in the prototyping stages, so documentation isn't available on low-level features yet.
• The out-of-the-box RPC handler does not provide the URI, session ID or call ID to the function that the call is routed to. This may be addressed in a later version with arg inspection/injection or async context vars.

Development

Unit tests can be run with:

pip install -e .
pytest