April 2018
Beginner to intermediate
406 pages
9h 33m
English
Next, we'll need two utility functions to abstract away some of the GenServer logic. We'll start by creating the function responsible for writing new data to our ETS Presence cache:
def write(topic, username, status) do row = %{ topic: topic, username: username, status: status, timestamp: DateTime.utc_now() } GenServer.cast(__MODULE__, {:write, row}) end
This function isn't doing nearly as much as it looks like it's doing: It takes in the topic, the user's username, and the status we want to record, builds a map from these, which includes the current timestamp, and then uses a GenServer message cast (an asynchronous call) to itself to write that row. We'll deal with this message later!
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