First, Manual Testing and New Assignment #
- What do we have working?
- What do we need next?
Hangman, pt2 #
Last time we built a basic Hangman game:
- React component.
- useState with two fields.
- We can render from those two fields by first calculating derived values and then outputting a DOM tree.
- Events modify the two fields and trigger a re-render.
Problems:
- Only one game at a time.
- Player can cheat.
- Game is single player.
- Only one game at a time.
- No high scores.
Solutions:
- Add a landing screen where we can punch in a game name.
- Discuss using a form vs. just React here.
- Add a channel.
- Add a GenServer for multiplayer.
- Talk about Agent vs. GenServer vs. DB
- Add a Supervisor
- Add a DB for high scores.
Supervisor example:
defmodule Inkfish.Itty.Sup do
use Supervisor
def start_link(arg) do
Supervisor.start_link(__MODULE__, arg, name: __MODULE__)
end
@impl true
def init(_arg) do
children = [
{DynamicSupervisor, strategy: :one_for_one, name: Inkfish.Itty.DynSup},
{Registry, keys: :unique, name: Inkfish.Itty.Reg}
]
Supervisor.init(children, strategy: :one_for_one)
end
Launching under DynamicSupervisor and calling via registry:
...
use GenServer
...
def start_link(state0) do
IO.puts(" =[Itty]= Start server with UUID #{state0.uuid}")
GenServer.start_link(__MODULE__, state0, name: reg(state0.uuid))
end
def reg(uuid) do
{:via, Registry, {Inkfish.Itty.Reg, uuid}}
end
def start(%Task{} = task) do
state0 = Map.delete(task, :__struct__)
spec = %{
id: __MODULE__,
start: {__MODULE__, :start_link, [state0]},
restart: :temporary
}
DynamicSupervisor.start_child(Inkfish.Itty.DynSup, spec)
end
def peek(uuid) do
if !Enum.empty?(Registry.lookup(Inkfish.Itty.Reg, uuid)) do
GenServer.call(reg(uuid), :peek)
else
{:error, :itty_not_found}
end
end
Now we can hit the DB for high scores if we still have time.
