From e73e379ab59840e8561b5730878f16e29ab06217 Mon Sep 17 00:00:00 2001
From: Mat Trudel <mat@geeky.net>
Date: Fri, 6 Dec 2024 08:52:42 -0500
Subject: [PATCH] Handle pipelined requests (#437)

* Fix error where we weren't maintaining tail buffer at the end of chunked reads

* Fix bug where we were throwing away pipelined requests during keepalive
---
 lib/bandit/http1/handler.ex        | 11 ++++++++++-
 lib/bandit/http1/socket.ex         |  5 +++--
 test/bandit/http1/request_test.exs | 16 ++++++++++++++++
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/lib/bandit/http1/handler.ex b/lib/bandit/http1/handler.ex
index 7b01aab2..5b64df6b 100644
--- a/lib/bandit/http1/handler.ex
+++ b/lib/bandit/http1/handler.ex
@@ -25,7 +25,16 @@ defmodule Bandit.HTTP1.Handler do
       if Keyword.get(state.opts.http_1, :clear_process_dict, true), do: clear_process_dict()
       gc_every_n_requests = Keyword.get(state.opts.http_1, :gc_every_n_keepalive_requests, 5)
       if rem(requests_processed, gc_every_n_requests) == 0, do: :erlang.garbage_collect()
-      {:continue, Map.put(state, :requests_processed, requests_processed)}
+
+      state = Map.put(state, :requests_processed, requests_processed)
+
+      # We have bytes that we've read but haven't yet processed, tail call handle_data to start
+      # reading the next request
+      if IO.iodata_length(transport.buffer) != 0 do
+        handle_data(transport.buffer, transport.socket, state)
+      else
+        {:continue, state}
+      end
     else
       {:close, state}
     end
diff --git a/lib/bandit/http1/socket.ex b/lib/bandit/http1/socket.ex
index 6534d8af..e8130c8b 100644
--- a/lib/bandit/http1/socket.ex
+++ b/lib/bandit/http1/socket.ex
@@ -239,8 +239,9 @@ defmodule Bandit.HTTP1.Socket do
     @dialyzer {:no_improper_lists, do_read_chunked_data!: 5}
     defp do_read_chunked_data!(socket, buffer, body, read_size, read_timeout) do
       case :binary.split(buffer, "\r\n") do
-        ["0", _] ->
-          {IO.iodata_to_binary(body), buffer}
+        ["0", "\r\n" <> rest] ->
+          # We should be reading (and ignoring) trailers here
+          {IO.iodata_to_binary(body), rest}
 
         [chunk_size, rest] ->
           chunk_size = String.to_integer(chunk_size, 16)
diff --git a/test/bandit/http1/request_test.exs b/test/bandit/http1/request_test.exs
index 124a9d63..190088b5 100644
--- a/test/bandit/http1/request_test.exs
+++ b/test/bandit/http1/request_test.exs
@@ -242,6 +242,22 @@ defmodule HTTP1RequestTest do
   end
 
   describe "keepalive requests" do
+    test "handles pipeline requests", context do
+      client = SimpleHTTP1Client.tcp_client(context)
+
+      Transport.send(
+        client,
+        String.duplicate("GET /hello_world HTTP/1.1\r\nHost: localhost\r\n\r\n", 50)
+      )
+
+      for _ <- 1..50 do
+        # Need to read the exact size of the expected response because SimpleHTTP1Client
+        # doesn't track 'rest' bytes and ends up throwing a bunch of responses on the floor
+        {:ok, bytes} = Transport.recv(client, 152)
+        assert({:ok, "200 OK", _, _} = SimpleHTTP1Client.parse_response(client, bytes))
+      end
+    end
+
     test "closes connection after max_requests is reached", context do
       context = http_server(context, http_1_options: [max_requests: 3])
       client = SimpleHTTP1Client.tcp_client(context)