geo: add geo-location utility

lib/toolshed.ex

@@ -16,7 +16,7 @@ defmodule Toolshed do
     * `dmesg/0`        - print kernel messages (Nerves-only)
     * `exit/0`         - exit out of an IEx session
     * `fw_validate/0`  - marks the current image as valid (check Nerves system if supported)
-    * `geo/0`          - print out a rough physical location
+    * `geo/1`          - print out a rough physical location
     * `grep/2`         - print out lines that match a regular expression
     * `hex/1`          - print a number as hex
     * `history/0`      - print out the IEx shell history

lib_src/core/geo.ex

@@ -0,0 +1,94 @@
+defmodule Toolshed.Core.Geo do
+  @whenwhere_url "http://whenwhere.nerves-project.org/"
+
+  @doc """
+  Geo-locate this Elixir instance
+
+  Options:
+
+  * `:ifname` - Network interface to use (e.g., `"eth0"`)
+  * `:whenwhere_url` - URL for the whenwhere server to query. Defaults to http://whenwhere.nerves-project.org
+  """
+  @spec geo(keyword()) :: :"do not show this result in output"
+  def geo(options \\ []) do
+    check_app(:inets)
+    check_app(:ssl)
+
+    do_geo(options) |> IO.puts()
+    IEx.dont_display_result()
+  end
+
+  defp do_geo(options) do
+    url = Keyword.get(options, :whenwhere_url, @whenwhere_url)
+
+    request_headers = [
+      {~c"user-agent", ~c"toolshed"},
+      {~c"content-type", ~c"application/x-erlang-binary"}
+    ]
+
+    case :httpc.request(
+           :get,
+           {url, request_headers},
+           [ssl: [verify: :verify_none]],
+           socket_opts: socket_opts(options)
+         ) do
+      {:ok, {_status, _headers, body}} ->
+        body |> :erlang.list_to_binary() |> :erlang.binary_to_term() |> format_geo_output()
+
+      {:error, reason} ->
+        error_message(reason)
+    end
+  rescue
+    e in MatchError -> error_message(e)
+  catch
+    :exit, reason -> error_message(reason)
+  end
+
+  defp extract_ip(ip_port_string) do
+    case Regex.run(~r/^(.*):\d+$/, ip_port_string) do
+      [_, ip_address] -> ip_address
+      _ -> []
+    end
+  end
+
+  defp format_geo_output(result) do
+    now = NaiveDateTime.from_iso8601!(result["now"])
+
+    local_now =
+      with {:ok, time_zone} <- Map.fetch(result, "time_zone"),
+           {:ok, utc} <- DateTime.from_naive(now, "Etc/UTC"),
+           {:ok, dt} <- DateTime.shift_zone(utc, time_zone) do
+        dt
+      else
+        _ -> nil
+      end
+
+    where =
+      [result["city"], result["country_region"], result["country"]]
+      |> Enum.filter(&Function.identity/1)
+      |> Enum.intersperse(", ")
+
+    [
+      "UTC Time  : ",
+      NaiveDateTime.to_string(now),
+      "\n",
+      if(local_now, do: ["Local time: ", DateTime.to_string(local_now), "\n"], else: []),
+      ["Location  : ", where, "\n"],
+      if(result["latitude"] && result["longitude"],
+        do: [
+          "Map       : https://www.openstreetmap.org/?mlat=",
+          result["latitude"],
+          "&mlon=",
+          result["longitude"],
+          "&zoom=12#map=12/",
+          result["latitude"],
+          "/",
+          result["longitude"],
+          "\n"
+        ],
+        else: []
+      ),
+      if(result["address"], do: ["Public IP : ", extract_ip(result["address"])], else: [])
+    ]
+  end
+end

test/toolshed/geo_test.exs

@@ -0,0 +1,15 @@
+defmodule Toolshed.GeoTest do
+  use ExUnit.Case
+  import ExUnit.CaptureIO
+
+  test "geo/1 returns at least the time" do
+    # Everything else is optional unfortunately
+    assert capture_io(&Toolshed.geo/0) =~ "UTC Time  : "
+  end
+
+  test "geo/1 supports overriding the server" do
+    assert capture_io(fn ->
+             Toolshed.geo(whenwhere_url: "http://not_a_server.nerves-project.org")
+           end) =~ "Something went wrong when making an HTTP request"
+  end
+end

test/toolshed_test.exs

@@ -6,6 +6,8 @@ defmodule ToolshedTest do
     cat: 1,
     cmd: 1,
     date: 0,
+    geo: 0,
+    geo: 1,
     grep: 2,
     hex: 1,
     history: 0,