Add leex and yecc files & Elixir interface for DMARC parse

1 files changed, 49 insertions, 0 deletions

diff --git a/lib/dmarc/parser.ex b/lib/dmarc/parser.ex
new file mode 100644
index 0000000..e4fd29b
--- /dev/null
+++ b/lib/dmarc/parser.ex
@@ -0,0 +1,49 @@
+defmodule Lithium.DMARC.Parser do
+  @moduledoc """
+  A wrapper around the `:dmarc_parser` yecc and leex parser.
+
+  This module is responsible for parsing DMARC records and returning a
+  map of the parsed values. It is then up to the `Lithium.DMARC.Policy`
+  module to validate and process these values.
+  """
+
+  def parse_policy(record) do
+    case :dmarc_lexer.string(String.to_charlist(record)) do
+      {:ok, tokens, _} ->
+        case :dmarc_parser.parse(tokens) do
+          {:ok, parsed} ->
+            {:ok, keyword_to_string_map(parsed)}
+
+          {:error, reason} ->
+            {:error, reason}
+
+          {:error, reason, _} ->
+            {:error, reason}
+        end
+
+      {:error, reason} ->
+        {:error, reason}
+
+      {:error, reason, _} ->
+        {:error, reason}
+    end
+  end
+
+  defp keyword_to_string_map(keyword_list) do
+    keyword_list
+    |> Enum.map(fn {k, v} ->
+      {k, convert_value(v)}
+    end)
+    |> Map.new()
+  end
+
+  defp convert_value(value) when is_list(value) and is_integer(hd(value)) do
+    to_string(value)
+  end
+
+  defp convert_value(value) when is_list(value) do
+    Enum.map(value, &convert_value/1)
+  end
+
+  defp convert_value(value), do: value
+end