Streaming: disconnect on keep_alive()

[luafran]

Hi

I have a use case where I want to connect to the streaming API for a period of time and then disconnect even when no tweet is received during that period.

When no tweet is received, I can check if defined duration has elapsed in StreamListener keep_alive(), but there is no mechanism to disconnect in this case since _read_loop() is not reading any return value from keep_alive() and there is no way to break the loop in this situation.

As a workaround I am rising a custom exception in my implementation of keep_alive() but this is not ideal, I understand that a better solution is to let keep_alive() return a boolean that when is false breaks the read loop, same as on_data(), on_status(), etc.

[anshudwibhashi]

I support this. I'd too rather have the keep_alive() function return a boolean to determine whether or not the connection continues to exist. Currently, my workaround is to raise an exception in the keep_alive function, and override the on_exception function to return false.

[aalberti333]

I would also like to see this implemented.

[Harmon758]

This should be resolved with 37e701e by allowing Stream.disconnect to disconnect the stream on the next keep-alive signal received.

I opted not to use the approach of allowing a False return value from the stream listener's on_keep_alive method to indicate that the stream should disconnect, as I intend to remove this for other stream listener methods in Tweepy v4.0 because it's an unclear functionality that should be considered an anti-pattern / bad practice. When necessary, explicitly calling the Stream.disconnect method in the relevant stream listener method is clearer and more straightforward.

I also intend to merge StreamListener into Stream in Tweepy v4.0, which will make doing this simpler and less recursive, i.e. using self.disconnect in the relevant listener method rather than requiring the Stream instance to be available in the relevant stream listener method.

Afterwards, I anticipate being able to simplify the handling of each line of data, so as to allow the stream to disconnect immediately if Stream.disconenct is called in the on_keep_alive method, rather than waiting until the next keep-alive signal (or other line of data).

[Harmon758]

I intend to remove this for other stream listener methods in Tweepy v4.0

This is now done, with 7fc85f6, 7756fa8, and e348c36.

I also intend to merge StreamListener into Stream in Tweepy v4.0

This is now done with 39abff4.

Afterwards, I anticipate being able to simplify the handling of each line of data, so as to allow the stream to disconnect immediately if Stream.disconenct is called in the on_keep_alive method, rather than waiting until the next keep-alive signal (or other line of data).

This was also done with 7756fa8.