feat: add self-grading Smart Cell

.gitignore

@@ -0,0 +1 @@
+.DS_Store

modules/2-owasp.livemd

@@ -1,14 +1,12 @@
 # ESCT: Part 2 - OWASP
 
 ```elixir
-Mix.install([
-  {:grading_client, path: "#{__DIR__}/grading_client"},
-  :bcrypt_elixir,
-  :httpoison,
-  {:absinthe, "~> 1.7.0"},
-  {:phoenix, "~> 1.0"},
-  {:plug, "~> 1.3.2"}
-])
+Mix.install(
+  [
+    {:grading_client, path: "#{__DIR__}/grading_client"}
+  ],
+  config_path: "#{__DIR__}/grading_client/config/config.exs"
+)
 
 md5_hash = :crypto.hash(:md5, "users_password")
 bcrypt_salted_hash = Bcrypt.hash_pwd_salt("users_password")
@@ -103,27 +101,55 @@ Notable CWEs included are CWE-259: Use of Hard-coded Password, CWE-327: Broken o
 
 _Please uncomment the function call that you believe is correct._
 
+<!-- livebook:{"attrs":"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","chunks":null,"kind":"Elixir.GradingClient.GradedCell","livebook_object":"smart_cell"} -->
+
 ```elixir
-defmodule PasswordCompare do
-  def option_one(password, md5_hash) do
-    case :crypto.hash(:md5, password) == md5_hash do
-      true -> :entry_granted_op1
-      false -> :entry_denied_op1
+result =
+  defmodule PasswordCompare do
+    def option_one(password, md5_hash) do
+      case :crypto.hash(:md5, password) == md5_hash do
+        true -> :entry_granted_op1
+        false -> :entry_denied_op1
+      end
     end
-  end
 
-  def option_two(password, bcrypt_salted_hash) do
-    case Bcrypt.verify_pass(password, bcrypt_salted_hash) do
-      true -> :entry_granted_op2
-      false -> :entry_denied_op2
+    def option_two(password, bcrypt_salted_hash) do
+      case Bcrypt.verify_pass(password, bcrypt_salted_hash) do
+        true -> :entry_granted_op2
+        false -> :entry_denied_op2
+      end
     end
   end
-end
 
-# DO NOT CHANGE CODE ABOVE THIS LINE =========================
+[module_id, question_id] =
+  "#OWASP:1\ndefmodule PasswordCompare do\n  def option_one(password, md5_hash) do\n    case :crypto.hash(:md5, password) == md5_hash do\n      true -> :entry_granted_op1\n      false -> :entry_denied_op1\n    end\n  end\n\n  def option_two(password, bcrypt_salted_hash) do\n    case Bcrypt.verify_pass(password, bcrypt_salted_hash) do\n      true -> :entry_granted_op2\n      false -> :entry_denied_op2\n    end\n  end\nend\n\n# DO NOT CHANGE CODE ABOVE THIS LINE =========================\n\n# PasswordCompare.option_one(\"users_password\", md5_hash)\n# PasswordCompare.option_two(\"users_password\", bcrypt_salted_hash)"
+  |> String.split("\n", parts: 2)
+  |> hd()
+  |> String.trim_leading("#")
+  |> String.split(":", parts: 2)
+
+module_id =
+  case %{"OWASP" => OWASP}[String.trim(module_id)] do
+    nil -> raise "invalid module id: #{module_id}"
+    module_id -> module_id
+  end
+
+question_id =
+  case Integer.parse(String.trim(question_id)) do
+    {id, ""} -> id
+    _ -> raise "invalid question id: #{question_id}"
+  end
+
+case GradingClient.check_answer(module_id, question_id, result) do
+  :correct ->
+    IO.puts([IO.ANSI.green(), "Correct!", IO.ANSI.reset()])
+
+  {:incorrect, help_text} when is_binary(help_text) ->
+    IO.puts([IO.ANSI.red(), "Incorrect: ", IO.ANSI.reset(), help_text])
 
-# PasswordCompare.option_one("users_password", md5_hash)
-# PasswordCompare.option_two("users_password", bcrypt_salted_hash)
+  _ ->
+    IO.puts([IO.ANSI.red(), "Incorrect.", IO.ANSI.reset()])
+end
 ```
 
 <!-- livebook:{"branch_parent_index":3} -->
@@ -244,19 +270,57 @@ Notable CWE included is CWE-1104: Use of Unmaintained Third-Party Components
 
 ### <span style="color:red">QUIZ</span>
 
-**Which of the outdated components currently installed is vulnerable?**
+**Which of the outdated components listed below is vulnerable?**
 
 _Please change the atom below to the name of the vulnerable package installed in this Livebook AND update the afflicted package._
 
-_HINT: Installed dependencies can be found at the very top, it was the very first cell you ran._
+_HINT: Check the changelogs for each dependency._
+
+<!-- livebook:{"attrs":"eyJtb2R1bGVfaWQiOm51bGwsInF1ZXN0aW9uX2lkIjpudWxsLCJzb3VyY2UiOiIjT1dBU1A6MlxuYW5zd2VyID0gXG4gIEtpbm8uSW5wdXQuc2VsZWN0KFwiQW5zd2VyXCIsIFtcbiAgICB7OmVjdG8sIFwiRWN0byB2Mi4yLjJcIn0sXG4gICAgezpueCwgXCJOeCB2MC41LjBcIn0sXG4gICAgezpwbHVnLCBcIlBsdWcgdjEuMy4yXCJ9XG4gIF0pXG5cbktpbm8ucmVuZGVyKGFuc3dlcilcblxuS2luby5JbnB1dC5yZWFkKGFuc3dlcikifQ","chunks":null,"kind":"Elixir.GradingClient.GradedCell","livebook_object":"smart_cell"} -->
 
 ```elixir
-# CHANGE ME
-vulnerable_dependency = :vulnerable_dependency
+result =
+  (
+    answer =
+      Kino.Input.select("Answer",
+        ecto: "Ecto v2.2.2",
+        nx: "Nx v0.5.0",
+        plug: "Plug v1.3.2"
+      )
+
+    Kino.render(answer)
+    Kino.Input.read(answer)
+  )
+
+[module_id, question_id] =
+  "#OWASP:2\nanswer = \n  Kino.Input.select(\"Answer\", [\n    {:ecto, \"Ecto v2.2.2\"},\n    {:nx, \"Nx v0.5.0\"},\n    {:plug, \"Plug v1.3.2\"}\n  ])\n\nKino.render(answer)\n\nKino.Input.read(answer)"
+  |> String.split("\n", parts: 2)
+  |> hd()
+  |> String.trim_leading("#")
+  |> String.split(":", parts: 2)
+
+module_id =
+  case %{"OWASP" => OWASP}[String.trim(module_id)] do
+    nil -> raise "invalid module id: #{module_id}"
+    module_id -> module_id
+  end
+
+question_id =
+  case Integer.parse(String.trim(question_id)) do
+    {id, ""} -> id
+    _ -> raise "invalid question id: #{question_id}"
+  end
+
+case GradingClient.check_answer(module_id, question_id, result) do
+  :correct ->
+    IO.puts([IO.ANSI.green(), "Correct!", IO.ANSI.reset()])
 
-# DO NOT CHANGE CODE BELOW THIS LINE ============================
-Application.spec(vulnerable_dependency)[:vsn] |> List.to_string() |> IO.puts()
-IO.puts(vulnerable_dependency)
+  {:incorrect, help_text} when is_binary(help_text) ->
+    IO.puts([IO.ANSI.red(), "Incorrect: ", IO.ANSI.reset(), help_text])
+
+  _ ->
+    IO.puts([IO.ANSI.red(), "Incorrect.", IO.ANSI.reset()])
+end
 ```
 
 <!-- livebook:{"branch_parent_index":3} -->

modules/grading_client/config/config.exs

@@ -0,0 +1 @@
+import Config

modules/grading_client/lib/grading_client.ex

@@ -7,29 +7,8 @@ defmodule GradingClient do
   Checks the answer to a question.
   """
 
-  @spec check_answer(any() | String.t(), integer(), integer()) :: :ok | {:error, String.t()}
-  def check_answer(answer, module_id, question_id) when not is_binary(answer) do
-    check_answer(module_id, question_id, "#{inspect(answer)}")
-  end
-
-  def check_answer(answer, module_id, question_id) do
-    # TODO: Make this configurable
-    url = "http://localhost:4000/api/answers/check"
-
-    headers = [
-      {"Content-Type", "application/json"}
-    ]
-
-    json = Jason.encode!(%{module_id: module_id, question_id: question_id, answer: answer})
-
-    %{body: body, status_code: 200} = HTTPoison.post!(url, json, headers)
-
-    %{"correct" => is_correct, "help_text" => help_text} = Jason.decode!(body)
-
-    if is_correct do
-      :ok
-    else
-      {:error, help_text}
-    end
+  @spec check_answer(any(), any(), any()) :: :correct | {:incorrect, String.t() | nil}
+  def check_answer(module_id, question_id, answer) do
+    GradingClient.Answers.check(module_id, question_id, answer)
   end
 end

modules/grading_client/lib/grading_client/answer.ex

@@ -0,0 +1,11 @@
+defmodule GradingClient.Answer do
+  @enforce_keys [:question_id, :module_id, :answer, :help_text]
+  defstruct [:question_id, :module_id, :answer, :help_text]
+
+  @type t :: %__MODULE__{
+          module_id: term(),
+          question_id: term(),
+          answer: term(),
+          help_text: term()
+        }
+end

modules/grading_client/lib/grading_client/answers.ex

@@ -0,0 +1,72 @@
+defmodule GradingClient.Answers do
+  @moduledoc """
+  This module is responsible for checking if an answer is correct.
+  It uses the `AnswerStore` to fetch the answer and compares if it is correct or not.
+  """
+  use GenServer
+
+  alias GradingClient.Answer
+
+  @table :answer_store
+
+  def start_link(opts) do
+    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
+  end
+
+  @impl true
+  def init(opts) do
+    :ets.new(@table, [:set, :named_table])
+
+    filename = opts[:filename]
+
+    {answers, _} = Code.eval_file(filename)
+
+    modules =
+      MapSet.new(answers, fn answer ->
+        :ets.insert(@table, {{answer.module_id, answer.question_id}, answer})
+        answer.module_id
+      end)
+
+    {:ok, %{modules: modules}}
+  end
+
+  @doc """
+  Checks if the given answer is correct.
+  """
+  @spec check(integer(), integer(), String.t()) :: :correct | {:incorrect, String.t()}
+  def check(module_id, question_id, answer) do
+    GenServer.call(__MODULE__, {:check, module_id, question_id, answer})
+  end
+
+  @doc """
+  Returns the list of modules.
+  """
+  @spec get_modules() :: [atom()]
+  def get_modules() do
+    GenServer.call(__MODULE__, :get_modules)
+  end
+
+  @impl true
+  def handle_call(:get_modules, _from, state) do
+    {:reply, state.modules, state}
+  end
+
+  @impl true
+  def handle_call({:check, module_id, question_id, answer}, _from, state) do
+    result =
+      case :ets.lookup(@table, {module_id, question_id}) do
+        [] ->
+          {:incorrect, "Question not found"}
+
+        [{_id, %Answer{answer: correct_answer, help_text: help_text}}] ->
+
+          if answer == correct_answer do
+            :correct
+          else
+            {:incorrect, help_text}
+          end
+      end
+
+    {:reply, result, state}
+  end
+end

modules/grading_client/lib/grading_client/application.ex

@@ -0,0 +1,17 @@
+defmodule GradingClient.Application do
+  use Application
+
+  def start(_type, _args) do
+    Kino.SmartCell.register(GradingClient.GradedCell)
+
+    default_filename = Path.join(:code.priv_dir(:grading_client), "answers.exs")
+
+    children = [
+      {GradingClient.Answers,
+       filename: Application.get_env(:grading_client, :answers_file, default_filename)}
+    ]
+
+    opts = [strategy: :one_for_one, name: GradingClient.Supervisor]
+    Supervisor.start_link(children, opts)
+  end
+end