From 0f4bebe2bd287aa02101c033036da43152afb534 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C5=82awomir=20St=C4=99pie=C5=84?= <sst@poczta.fm>
Date: Tue, 25 Feb 2020 09:16:22 +0100
Subject: [PATCH] reader: unzip and untar data without checking the filename
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Since filename can be also an URL, it's more wise to make decision based
on data and not the filename.

This commit will try to unzip and untar the data, and if it fails it
will pass the data down the pipe.

Signed-off-by: Sławomir Stępień <sst@poczta.fm>
---
 lib/mmdb2/reader.ex | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/lib/mmdb2/reader.ex b/lib/mmdb2/reader.ex
index b5b6d7d..d4d797a 100644
--- a/lib/mmdb2/reader.ex
+++ b/lib/mmdb2/reader.ex
@@ -12,8 +12,8 @@ defmodule Geolix.Adapter.MMDB2.Reader do
       {:ok, {{_, 200, _}, _, body}} ->
         body
         |> IO.iodata_to_binary()
-        |> maybe_gunzip(filename)
-        |> maybe_untar(filename)
+        |> maybe_gunzip()
+        |> maybe_untar()
         |> MMDB2Decoder.parse_database()
 
       {:ok, {{_, status, _}, _, _}} ->
@@ -29,8 +29,8 @@ defmodule Geolix.Adapter.MMDB2.Reader do
       {:ok, _} ->
         filename
         |> File.read!()
-        |> maybe_gunzip(filename)
-        |> maybe_untar(filename)
+        |> maybe_gunzip()
+        |> maybe_untar()
         |> MMDB2Decoder.parse_database()
 
       error ->
@@ -48,21 +48,18 @@ defmodule Geolix.Adapter.MMDB2.Reader do
     end
   end
 
-  defp maybe_untar(data, filename) do
-    if String.ends_with?(filename, [".tar", ".tar.gz"]) do
-      {:ok, files} = :erl_tar.extract({:binary, data}, [:memory])
-
-      find_mmdb_contents(files)
-    else
-      data
+  defp maybe_untar(data) do
+    case :erl_tar.extract({:binary, data}, [:memory]) do
+      {:ok, files} -> find_mmdb_contents(files)
+      {:error, _} -> data
     end
   end
 
-  defp maybe_gunzip(data, filename) do
-    if String.ends_with?(filename, ".gz") do
+  defp maybe_gunzip(data) do
+    try do
       :zlib.gunzip(data)
-    else
-      data
+    rescue
+      _ -> data
     end
   end
 end