TempFile module to handle random file names

lib/feed_reader/collector.ex

@@ -123,8 +123,7 @@ defmodule FeedReader.Collector do
     do: {:ok, %ParseResult{feed: feed, items: Enum.reverse(items)}}
 
   defp temporary_path do
-    path =
-      Path.join(System.tmp_dir!(), "feed_reader-parse-#{System.unique_integer([:positive])}.xml")
+    path = FeedReader.TempFile.random_file("feed_reader-parse")
 
     case File.open(path, [:write, :binary, :exclusive]) do
       {:ok, file} ->

lib/feed_reader/downloader.ex

@@ -233,11 +233,7 @@ defmodule FeedReader.Downloader do
   defp open_temp_file(0), do: {:error, :eexist}
 
   defp open_temp_file(attempts) do
-    path =
-      Path.join(
-        System.tmp_dir!(),
-        "feed_reader-download-#{System.unique_integer([:positive])}.xml"
-      )
+    path = FeedReader.TempFile.random_file("feed_reader-download")
 
     case File.open(path, [:write, :binary, :exclusive]) do
       {:ok, file} -> {:ok, path, file}

lib/feed_reader/temp_file.ex

@@ -0,0 +1,11 @@
+defmodule FeedReader.TempFile do
+  @moduledoc false
+
+  @spec random_file(String.t()) :: String.t()
+  def random_file(base_name \\ "feed_reader") do
+    filename =
+      "#{base_name}-#{:crypto.strong_rand_bytes(16) |> Base.encode16(case: :lower)}.xml"
+
+    Path.join(System.tmp_dir!(), filename)
+  end
+end