這樣做的正確方法是不要在您的頻道中捕捉退出,而是讓另一個進程監視您。當你下樓時,它可以調用回調。下面是一個片段,讓你開始:
# lib/my_app.ex
children = [
...
worker(ChannelWatcher, [:rooms])
]
# web/channels/room_channel.ex
def join("rooms:", <> id, params, socket) do
uid = socket.assigns.user_id]
:ok = ChannelWatcher.monitor(:rooms, self(), {__MODULE__, :leave, [id, uid]})
{:ok, socket}
end
def leave(room_id, user_id) do
# handle user leaving
end
# lib/my_app/channel_watcher.ex
defmodule ChannelWatcher do
use GenServer
## Client API
def monitor(server_name, pid, mfa) do
GenServer.call(server_name, {:monitor, pid, mfa})
end
def demonitor(server_name, pid) do
GenServer.call(server_name, {:demonitor, pid})
end
## Server API
def start_link(name) do
GenServer.start_link(__MODULE__, [], name: name)
end
def init(_) do
Process.flag(:trap_exit, true)
{:ok, %{channels: HashDict.new()}}
end
def handle_call({:monitor, pid, mfa}, _from, state) do
Process.link(pid)
{:reply, :ok, put_channel(state, pid, mfa)
end
def handle_call({:demonitor, pid}, _from, state) do
case HashDict.fetch(state.channels, pid) do
:error -> {:reply, :ok, state}
{:ok, _mfa} ->
Process.unlink(pid)
{:reply, :ok, drop_channel(state, pid)}
end
end
def handle_info({:EXIT, pid, _reason}, state) do
case HashDict.fetch(state.channels, pid) do
:error -> {:noreply, state}
{:ok, {mod, func, args}} ->
Task.start_link(fn -> apply(mod, func, args) end)
{:noreply, drop_channel(state, pid)}
end
end
defp drop_channel(state, pid) do
%{state | channels: HashDict.delete(state.channels, pid)}}
end
defp put_channel(state, pid, mfa) do
%{state | channels: HashDict.put(channels, pid, mfa)}}
end
end
我剛剛注意到,服務器並不總是識別彈出窗口關閉時。所以我希望我的問題的解決方案也能解決這個問題。 –