From 29eba22548bc00d46d4ba0126a6bcd49e4a8a0b1 Mon Sep 17 00:00:00 2001
From: Wojtek Mach <wojtek@wojtekmach.pl>
Date: Fri, 25 Aug 2023 20:28:58 +0200
Subject: [PATCH] Revert unrelated changes

---
 lib/req/steps.ex        | 56 +++++++++++++++++++++++++----------------
 test/req/steps_test.exs | 21 ++++++++--------
 2 files changed, 44 insertions(+), 33 deletions(-)

diff --git a/lib/req/steps.ex b/lib/req/steps.ex
index c6b6d978..0d3ae33e 100644
--- a/lib/req/steps.ex
+++ b/lib/req/steps.ex
@@ -862,7 +862,9 @@ defmodule Req.Steps do
   | _other_       | Returns data as is                              |
 
   This step updates the following headers to reflect the changes:
-  - `content-length` is set to the length of the decompressed body
+
+    * `content-length` is set to the length of the decompressed body
+    * `content-encoding` is removed
 
   ## Options
 
@@ -904,49 +906,59 @@ defmodule Req.Steps do
     if request.options[:raw] do
       {request, response}
     else
-      compression_algorithms = get_content_encoding_header(response.headers)
-      decompressed_body = decompress_body(response.body, compression_algorithms)
+      codecs = get_content_encoding_header(response.headers)
+      {decompressed_body, unknown_codecs} = decompress_body(codecs, response.body, [])
       decompressed_content_length = decompressed_body |> byte_size() |> to_string()
 
       response =
         %Req.Response{response | body: decompressed_body}
         |> Req.Response.put_header("content-length", decompressed_content_length)
 
+      response =
+        if unknown_codecs == [] do
+          Req.Response.delete_header(response, "content-encoding")
+        else
+          Req.Response.put_header(response, "content-encoding", Enum.join(unknown_codecs, ", "))
+        end
+
       {request, response}
     end
   end
 
-  defp decompress_body(body, algorithms) do
-    Enum.reduce(algorithms, body, &decompress_with_algorithm(&1, &2))
+  defp decompress_body([gzip | rest], body, acc) when gzip in ["gzip", "x-gzip"] do
+    decompress_body(rest, :zlib.gunzip(body), acc)
   end
 
-  defp decompress_with_algorithm(gzip, body) when gzip in ["gzip", "x-gzip"] do
-    :zlib.gunzip(body)
-  end
-
-  defp decompress_with_algorithm("br", body) do
+  defp decompress_body(["br" | rest], body, acc) do
     if brotli_loaded?() do
       {:ok, decompressed} = :brotli.decode(body)
-      decompressed
+      decompress_body(rest, decompressed, acc)
     else
-      raise("`:brotli` decompression library not loaded")
+      Logger.debug("decompress_body: :brotli library not loaded, skipping brotli decompression")
+      decompress_body(rest, body, ["br" | acc])
     end
   end
 
-  defp decompress_with_algorithm("zstd", body) do
+  defp decompress_body(["zstd" | rest], body, acc) do
     if ezstd_loaded?() do
-      :ezstd.decompress(body)
+      decompress_body(rest, :ezstd.decompress(body), acc)
     else
-      raise("`:ezstd` decompression library not loaded")
+      Logger.debug("decompress_body: :ezstd library not loaded, skipping zstd decompression")
+      decompress_body(rest, body, ["zstd" | acc])
     end
   end
 
-  defp decompress_with_algorithm("identity", body) do
-    body
+  defp decompress_body(["identity" | rest], body, acc) do
+    decompress_body(rest, body, acc)
+  end
+
+  defp decompress_body([codec | rest], body, acc) do
+    Logger.debug("decompress_body: algorithm #{inspect(codec)} is not supported")
+    decompress_body(rest, body, [codec | acc])
   end
 
-  defp decompress_with_algorithm(_algorithm, body) do
-    body
+  defp decompress_body([], body, acc) do
+    {body, acc}
   end
 
   defmacrop nimble_csv_loaded? do
@@ -1423,14 +1435,14 @@ defmodule Req.Steps do
     end
   end
 
-  defp apply_retry( fun, request, response_or_exception)
+  defp apply_retry(fun, request, response_or_exception)
 
-  defp apply_retry(fun, _request, response_or_exception) when is_function( fun, 1) do
+  defp apply_retry(fun, _request, response_or_exception) when is_function(fun, 1) do
     IO.warn("`retry: fun/1` has been deprecated in favor of `retry: fun/2`")
     fun.(response_or_exception)
   end
 
-  defp apply_retry(fun, request, response_or_exception) when is_function( fun, 2) do
+  defp apply_retry(fun, request, response_or_exception) when is_function(fun, 2) do
     fun.(request, response_or_exception)
   end
 
diff --git a/test/req/steps_test.exs b/test/req/steps_test.exs
index 8712c704..625d3f7b 100644
--- a/test/req/steps_test.exs
+++ b/test/req/steps_test.exs
@@ -390,17 +390,16 @@ defmodule Req.StepsTest do
       assert String.to_integer(content_length) == byte_size(body)
     end
 
-# raises
-#    test "delete content-encoding header", c do
-#      Bypass.expect(c.bypass, "GET", "/", fn conn ->
-#        conn
-#        |> Plug.Conn.put_resp_header("content-encoding", "x-gzip")
-#        |> Plug.Conn.send_resp(200, :zlib.gzip("foo"))
-#      end)
-#
-#      resp = Req.get!(c.url)
-#      assert [] = Req.Response.get_header(resp, "content-encoding")
-#    end
+    test "delete content-encoding header", c do
+      Bypass.expect(c.bypass, "GET", "/", fn conn ->
+        conn
+        |> Plug.Conn.put_resp_header("content-encoding", "x-gzip")
+        |> Plug.Conn.send_resp(200, :zlib.gzip("foo"))
+      end)
+
+      resp = Req.get!(c.url)
+      assert [] = Req.Response.get_header(resp, "content-encoding")
+    end
   end
 
   describe "output" do