Websocket(url_or_request, json=True, loop=None)¶
Wraps an aiohttp websocket to have an API matching RTCBot. The websocket can be given either a URL to connect to:
ws = Websocket("http://localhost:8080/ws") msg = await ws.get()
It can also be used in a server context to complete the connection:
@routes.get("/ws") async def websocketHandler(request): ws = Websocket(request) msg = await ws.get()
Naturally, just like all other parts of rtcbot, you can also subscribe and putSubscription instead of manually calling get and put_nowait.
Cleans up and closes the object.
Returns whether the object was closed. This includes both thrown exceptions, and clean exits.
If there is an error that causes the underlying process to crash, this property will hold the actual
Exceptionthat was thrown:
if myobject.error is not None: print("Oh no! There was an error:",myobject.error)
This property is offered for convenience, but usually, you will want to subscribe to the error by using
onError(), which will notify your app when the issue happens.
If the error is not None, the object is considered crashed, and no longer processing data.
Behaves similarly to
subscribe().get(). On the first call, creates a default subscription, and all subsequent calls to
get()use that subscription.
data = await myobj.get() # Creates subscription on first call data = await myobj.get() # Same subscription myobj.unsubscribe() data2 = await myobj.get() # A new subscription
The above code is equivalent to the following:
defaultSubscription = myobj.subscribe() data = await defaultSubscription.get() data = await defaultSubscription.get() myobj.unsubscribe(defaultSubscription) newDefaultSubscription = myobj.subscribe() data = await newDefaultSubscription.get()
This is mainly useful for connections - they can be closed remotely. This allows handling the close event.
@myobj.onClose def closeCallback(): print("Closed!)
Be aware that this is equivalent to explicitly awaiting the object:
Since most data processing happens in the background, the object might encounter an error, and the data processing might crash. If there is a crash, the object is considered dead, and no longer gathering data.
To catch these errors, when an unhandled exception happens, the error event is fired, with the associated
Exception. This function allows you to subscribe to these events:
@myobj.onError def error_happened(err): print("Crap, stuff just crashed: ",err)
err = await myobj.onError()
Creating the class does not mean that the object is ready to process data. When created, the object starts an initialization procedure in the background, and once this procedure is complete, and any spawned background workers are ready to process data, it fires a ready event.
This function allows you to listen for this event:
@myobj.onReady def readyCallback(): print("Ready!)
The function works in exactly the same way as a
subscribe(), meaning that you can pass it a coroutine, or even await it directly:
The object will automatically handle any subscriptions or inserts that happen while it is initializing, so you generally don’t need to worry about the ready event, unless you need exact control.
Given a subscription, such that await subscription.get() returns successive pieces of data, keeps reading the subscription forever:
q = asyncio.Queue() # an asyncio.Queue has a get() coroutine myobj.putSubscription(q) q.put_nowait(data)
Equivalent to doing the following in the background:
while True: myobj.put_nowait(await q.get())
You can replace a currently running subscription with a new one at any point in time:
q1 = asyncio.Queue() myobj.putSubscription(q1) assert myobj.subscription == q1 q2 = asyncio.Queue() myobj.putSubscription(q2) assert myobj.subscription == q2
This function allows you to directly send data to the object, without needing to go through a subscription:
while True: data = get_data() myobj.put_nowait(data)
put_nowait()method is the simplest way to process a new chunk of data.
This is True when the class has been fully initialized, and is ready to process data:
if not myobject.ready: print("Not ready to process data")
This property is offered for convenience, but if you want to be notifed when ready to process data, you will want to use the
onReady()function, which will allow you to set up a callback/coroutine to wait until initialized.
You usually don’t need to check the ready state, since all functions for getting/putting data will work even if the class is still starting up in the background.
Stops reading the current subscription:
q = asyncio.Queue() myobj.putSubscription(q) assert myobj.subscription == q myobj.stopSubscription() assert myobj.subscription is None # You can then subscribe again (or put_nowait) myobj.putSubscription(q) assert myobj.subscription == q
The object is not affected, other than no longer listening to the subscription, and not processing new data until something is inserted.
Allows subscribing to new data as it comes in, returning a subscription (see Subscriptions):
s = myobj.subscribe() while True: data = await s.get() print(data)
There can be multiple subscriptions active at the same time, each of which get identical data. Each call to
subscribe()returns a new, independent subscription:
s1 = myobj.subscribe() s2 = myobj.subscribe() while True: assert await s1.get()== await s2.get()
This function can also be used as a callback:
@myobj.subscribe def newData(data): print("Got data:",data)
If passed an argument, it attempts to use the given callback/coroutine/subscription to notify of incoming data.
Parameters: subscription (optional) –
- An optional existing subscription to subscribe to. This can be one of 3 things:
- An object which has the method put_nowait (see Subscriptions):
q = asyncio.Queue() myobj.subscribe(q) while True: data = await q.get() print(data)
- A callback function - this will be called the moment new data is inserted:
@myobj.subscribe def myfunction(data): print(data)
- An coroutine callback - A future of this coroutine is created on each insert:
@myobj.subscribe async def myfunction(data): await asyncio.sleep(5) print(data)
- An object which has the method put_nowait (see Subscriptions):
Returns: A subscription. If one was passed in, returns the passed in subscription:
q = asyncio.Queue() ret = thing.subscribe(q) assert ret==q
Returns the currently active subscription:
q = asyncio.Queue() myobj.putSubscription(q) assert myobj.subscription == q myobj.stopSubscription() assert myobj.subscription is None myobj.put_nowait(data) assert myobj.subscription is None
Removes the given subscription, so that it no longer gets updated:
subs = myobj.subscribe() myobj.unsubscribe(subs)
If no argument is given, removes the default subscription created by get(). If none exists, then does nothing.
Parameters: subscription (optional) – Anything that was passed into/returned from
Removes all currently active subscriptions, including the default one if it was intialized.