bring token back

lib/farmbot/jwt.ex

@@ -0,0 +1,41 @@
+defmodule Farmbot.Jwt do
+  @moduledoc "Functions for dealing with the Farmbot JSON Web Token"
+
+  defstruct [
+    :bot,
+    :exp,
+    :iss,
+    :mqtt,
+    :os_update_server,
+    :sub
+  ]
+
+  @typedoc "Type def for Farmbot Web Token."
+  @type t :: %__MODULE__{
+    bot: binary,
+    exp: number,
+    iss: binary,
+    mqtt: binary,
+    os_update_server: binary,
+    sub: binary
+  }
+
+  @doc "Decode a token."
+  @spec decode(binary) :: {:ok, t} | {:error, term}
+  def decode(tkn) do
+    body = tkn |> String.split(".") |> Enum.at(1)
+    with {:ok, json} <- Base.decode64(body, padding: false),
+         {:ok, jwt}  <- Poison.decode(json, as: %__MODULE__{}),
+         do: {:ok, jwt}
+  end
+
+  @doc "Decodes a token, raises if it fails."
+  @spec decode!(binary) :: t | no_return
+  def decode!(tkn) do
+    case decode(tkn) do
+      {:ok, tkn} -> tkn
+      :error -> raise "Failed to base64 decode."
+      {:error, {:invalid, _char, _pos}} -> raise "Failed to json decode."
+    end
+  end
+end

test/farmbot/jwt_test.exs

@@ -0,0 +1,61 @@
+defmodule Farmbot.JwtTest do
+  @moduledoc "Tests Token functions."
+
+  @token "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJzdWIiOiJhZG1pbkBhZG1pbi5jb20iLCJpYXQiOjE1MDI0Mjc2MDUsImp0aSI6IjA3ZDk1MmRjLWQ2MDktNGRiYi04NTcwLTIxMTNkM2Q2ZWMzOSIsImlzcyI6Ii8vMTkyLjE2OC4yOS4yMDQ6MzAwMCIsImV4cCI6MTUwNTg4MzYwNSwibXF0dCI6IjE5Mi4xNjguMjkuMjA0Iiwib3NfdXBkYXRlX3NlcnZlciI6Imh0dHBzOi8vYXBpLmdpdGh1Yi5jb20vcmVwb3MvZmFybWJvdC9mYXJtYm90X29zL3JlbGVhc2VzL2xhdGVzdCIsImZ3X3VwZGF0ZV9zZXJ2ZXIiOiJodHRwczovL2FwaS5naXRodWIuY29tL3JlcG9zL0Zhcm1ib3QvZmFybWJvdC1hcmR1aW5vLWZpcm13YXJlL3JlbGVhc2VzL2xhdGVzdCIsImJvdCI6ImRldmljZV8yIn0.twtAOS9PXtkSB-a3Qjm3HrJSM7Nfm7oWOc8d4BFb7nBOaB3eGDUB4sb5u7pjAgMo37egIbAatKKkHlh_o9uNDJvrs9aPsLAn6O8dN_CDCkenjNyrbQjI8i_hjtL28X9AyHLOe1G0A8V8nRs4hZ8x5AcQSH8DkhaaRaBuh-0u1Yesfo7nwFIl34LTCoZ9amrdzHvIn0xP35BaPoEGziqolqtNJ5an2Bps4JGBV_kNSlODwGxPFESHO3uL1PrTgaXkM3_FSZpY7NxbgxC50ok9TspeMRLjluqntzyJG1EadxgHkbVOG0kuPH6R3Pa6UfkDNzBv7DWDHk4mOYPcDdABbQ"
+
+  use ExUnit.Case
+
+  doctest Farmbot.Jwt
+
+  alias Farmbot.Jwt
+  setup do
+    [token: @token]
+  end
+
+  test "decodes a token", %{token: tkn} do
+    r = Jwt.decode(tkn)
+    assert match?({:ok, %Farmbot.Jwt{}}, r)
+
+    {:ok, token} = r
+    assert Jwt.decode!(tkn) == token
+    assert token.sub == "admin@admin.com"
+    assert token.bot == "device_2"
+    assert token.exp == 1505883605
+    assert token.iss == "//192.168.29.204:3000"
+    assert token.mqtt == "192.168.29.204"
+  end
+
+  test "Gives :error when it can't be decoded as bas64", %{token: tkn} do
+    [head, _body, foot] = String.split(tkn, ".")
+    tkn = [head, "not_a_valid_token", foot] |> Enum.join(".")
+    r = Jwt.decode(tkn)
+    refute match?({:ok, _}, r)
+    assert r == :error
+  end
+
+  test "Gives Poison Error when it can't be decoded as json", %{token: tkn} do
+    [head, _body, foot] = String.split(tkn, ".")
+    not_token = Base.encode64 "hello world", padding: :false
+    tkn = [head, not_token, foot] |> Enum.join(".")
+    r = Jwt.decode(tkn)
+    refute match?({:ok, _}, r)
+    assert r == {:error, {:invalid, "h", 0}}
+  end
+
+  test "raises on bad token because base64", %{token: tkn} do
+    [head, _body, foot] = String.split(tkn, ".")
+    tkn = [head, "not_a_valid_token", foot] |> Enum.join(".")
+    assert_raise RuntimeError, "Failed to base64 decode.", fn() ->
+      Jwt.decode!(tkn)
+    end
+  end
+
+  test "Raises on bad json.", %{token: tkn} do
+    [head, _body, foot] = String.split(tkn, ".")
+    not_token = Base.encode64 "hello world", padding: :false
+    tkn = [head, not_token, foot] |> Enum.join(".")
+    assert_raise RuntimeError, "Failed to json decode.", fn() ->
+      Jwt.decode!(tkn)
+    end
+  end
+end