285 lines
9.9 KiB
Python
285 lines
9.9 KiB
Python
import os, sys, json, contextlib, random
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from twisted.internet import task, defer, endpoints
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from twisted.application import service, internet
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from twisted.web import server, static, resource
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from wormhole import journal, wormhole
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# considerations for state management:
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# * be somewhat principled about the data (e.g. have a schema)
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# * discourage accidental schema changes
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# * avoid surprise mutations by app code (don't hand out mutables)
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# * discourage app from keeping state itself: make state object easy enough
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# to use for everything. App should only hold objects that are active
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# (Services, subscribers, etc). App must wire up these objects each time.
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def parse(args):
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raise NotImplementedError
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def update_my_state():
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raise NotImplementedError
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class State(object):
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@classmethod
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def create_empty(klass):
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self = klass()
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# to avoid being tripped up by state-mutation side-effect bugs, we
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# hold the serialized state in RAM, and re-deserialize it each time
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# someone asks for a piece of it. # iid->invitation_stat
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empty = {"version": 1,
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"invitations": {},
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"contacts": [],
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}
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self._bytes = json.dumps(empty).encode("utf-8")
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return self
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@classmethod
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def from_filename(klass, fn):
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self = klass()
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with open(fn, "rb") as f:
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bytes = f.read()
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self._bytes = bytes
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# version check
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data = self._as_data()
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assert data["version"] == 1
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# schema check?
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return self
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def save_to_filename(self, fn):
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tmpfn = fn + ".tmp"
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with open(tmpfn, "wb") as f:
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f.write(self._bytes)
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os.rename(tmpfn, fn)
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def _as_data(self):
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return json.loads(bytes.decode("utf-8"))
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@contextlib.contextmanager
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def _mutate(self):
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data = self._as_data()
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yield data # mutable
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self._bytes = json.dumps(data).encode("utf-8")
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def get_all_invitations(self):
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return self._as_data()["invitations"]
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def add_invitation(self, iid, invitation_state):
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with self._mutate() as data:
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data["invitations"][iid] = invitation_state
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def update_invitation(self, iid, invitation_state):
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with self._mutate() as data:
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assert iid in data["invitations"]
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data["invitations"][iid] = invitation_state
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def remove_invitation(self, iid):
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with self._mutate() as data:
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del data["invitations"][iid]
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def add_contact(self, contact):
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with self._mutate() as data:
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data["contacts"].append(contact)
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class Root(resource.Resource):
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pass
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class Status(resource.Resource):
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def __init__(self, c):
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resource.Resource.__init__(self)
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self._call = c
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def render_GET(self, req):
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data = self._call()
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req.setHeader(b"content-type", "text/plain")
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return data
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class Action(resource.Resource):
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def __init__(self, c):
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resource.Resource.__init__(self)
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self._call = c
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def render_POST(self, req):
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req.setHeader(b"content-type", "text/plain")
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try:
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args = json.load(req.content)
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except ValueError:
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req.setResponseCode(500)
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return b"bad JSON"
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data = self._call(args)
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return data
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class Agent(service.MultiService):
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def __init__(self, basedir, reactor):
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service.MultiService.__init__(self)
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self._basedir = basedir
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self._reactor = reactor
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root = Root()
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site = server.Site(root)
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ep = endpoints.serverFromString(reactor, "tcp:8220")
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internet.StreamServerEndpointService(ep, site).setServiceParent(self)
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self._jm = journal.JournalManager(self._save_state)
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root.putChild(b"", static.Data("root", "text/plain"))
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root.putChild(b"list-invitations", Status(self._list_invitations))
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root.putChild(b"invite", Action(self._invite)) # {petname:}
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root.putChild(b"accept", Action(self._accept)) # {petname:, code:}
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self._state_fn = os.path.join(self._basedir, "state.json")
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self._state = State.from_filename(self._state_fn)
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self._wormholes = {}
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for iid, invitation_state in self._state.get_all_invitations().items():
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def _dispatch(event, *args, **kwargs):
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self._dispatch_wormhole_event(iid, event, *args, **kwargs)
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w = wormhole.journaled_from_data(invitation_state["wormhole"],
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reactor=self._reactor,
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journal=self._jm,
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event_handler=self,
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event_handler_args=(iid,))
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self._wormholes[iid] = w
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w.setServiceParent(self)
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def _save_state(self):
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self._state.save_to_filename(self._state_fn)
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def _list_invitations(self):
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inv = self._state.get_all_invitations()
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lines = ["%d: %s" % (iid, inv[iid]) for iid in sorted(inv)]
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return b"\n".join(lines) + b"\n"
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def _invite(self, args):
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print("invite", args)
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petname = args["petname"]
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# it'd be better to use a unique object for the event_handler
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# correlation, but we can't store them into the state database. I'm
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# not 100% sure we need one for the database: maybe it should hold a
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# list instead, and assign lookup keys at runtime. If they really
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# need to be serializable, they should be allocated rather than
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# random.
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iid = random.randint(1, 1000)
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my_pubkey = random.randint(1, 1000)
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with self._jm.process():
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w = wormhole.journaled(reactor=self._reactor, journal=self._jm,
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event_handler=self,
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event_handler_args=(iid,))
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self._wormholes[iid] = w
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w.setServiceParent(self)
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w.get_code() # event_handler means code returns via callback
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invitation_state = {"wormhole": w.to_data(),
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"petname": petname,
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"my_pubkey": my_pubkey,
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}
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self._state.add_invitation(iid, invitation_state)
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return b"ok"
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def _accept(self, args):
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print("accept", args)
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petname = args["petname"]
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code = args["code"]
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iid = random.randint(1, 1000)
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my_pubkey = random.randint(2, 2000)
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with self._jm.process():
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w = wormhole.journaled(reactor=self._reactor, journal=self._jm,
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event_dispatcher=self,
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event_dispatcher_args=(iid,))
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w.set_code(code)
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md = {"my_pubkey": my_pubkey}
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w.send(json.dumps(md).encode("utf-8"))
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invitation_state = {"wormhole": w.to_data(),
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"petname": petname,
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"my_pubkey": my_pubkey,
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}
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self._state.add_invitation(iid, invitation_state)
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return b"ok"
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# dispatch options:
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# * register one function, which takes (eventname, *args)
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# * to handle multiple wormholes, app must give is a closure
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# * register multiple functions (one per event type)
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# * register an object, with well-known method names
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# * extra: register args and/or kwargs with the callback
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#
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# events to dispatch:
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# generated_code(code)
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# got_verifier(verifier_bytes)
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# verified()
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# got_data(data_bytes)
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# closed()
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def wormhole_dispatch_got_code(self, code, iid):
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# we're already in a jm.process() context
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invitation_state = self._state.get_all_invitations()[iid]
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invitation_state["code"] = code
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self._state.update_invitation(iid, invitation_state)
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self._wormholes[iid].set_code(code)
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# notify UI subscribers to update the display
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def wormhole_dispatch_got_verifier(self, verifier, iid):
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pass
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def wormhole_dispatch_verified(self, _, iid):
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pass
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def wormhole_dispatch_got_data(self, data, iid):
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invitation_state = self._state.get_all_invitations()[iid]
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md = json.loads(data.decode("utf-8"))
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contact = {"petname": invitation_state["petname"],
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"my_pubkey": invitation_state["my_pubkey"],
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"their_pubkey": md["my_pubkey"],
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}
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self._state.add_contact(contact)
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self._wormholes[iid].close() # now waiting for "closed"
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def wormhole_dispatch_closed(self, _, iid):
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self._wormholes[iid].disownServiceParent()
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del self._wormholes[iid]
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self._state.remove_invitation(iid)
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def handle_app_event(self, args, ack_f): # sample function
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# Imagine here that the app has received a message (not
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# wormhole-related) from some other server, and needs to act on it.
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# Also imagine that ack_f() is how we tell the sender that they can
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# stop sending the message, or how we ask our poller/subscriber
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# client to send a DELETE message. If the process dies before ack_f()
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# delivers whatever it needs to deliver, then in the next launch,
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# handle_app_event() will be called again.
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stuff = parse(args) # noqa
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with self._jm.process():
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update_my_state()
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self._jm.queue_outbound(ack_f)
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def create(reactor, basedir):
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os.mkdir(basedir)
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s = State.create_empty()
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s.save(os.path.join(basedir, "state.json"))
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return defer.succeed(None)
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def run(reactor, basedir):
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a = Agent(basedir, reactor)
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a.startService()
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print("agent listening on http://localhost:8220/")
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d = defer.Deferred()
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return d
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if __name__ == "__main__":
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command = sys.argv[1]
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basedir = sys.argv[2]
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if command == "create":
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task.react(create, (basedir,))
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elif command == "run":
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task.react(run, (basedir,))
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else:
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print("Unrecognized subcommand '%s'" % command)
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sys.exit(1)
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