Read response when client closes connection #1232 (#1233)

* Read response when client closes connection #1232

* Fix edge case were client responds with invalid header

* Follow linter suggestions for tests

* Changes after review

* Reafactor error check after review

* Handle connection reset on windows

* Remove format string from test where not needed

* Run connection reset tests not on Windows

1 files changed, 136 insertions, 0 deletions

diff --git a/client_unix_test.go b/client_unix_test.go
new file mode 100644
index 0000000..f369111
--- /dev/null
+++ b/client_unix_test.go
@@ -0,0 +1,136 @@
+//go:build !windows
+// +build !windows
+
+package fasthttp
+
+import (
+	"io"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+// See issue #1232
+func TestRstConnResponseWhileSending(t *testing.T) {
+	const expectedStatus = http.StatusTeapot
+	const payload = "payload"
+
+	srv, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer srv.Close()
+
+	go func() {
+		for {
+			conn, err := srv.Accept()
+			if err != nil {
+				return
+			}
+
+			// Read at least one byte of the header
+			// Otherwise we would have an unsolicited response
+			_, err = ioutil.ReadAll(io.LimitReader(conn, 1))
+			if err != nil {
+				t.Error(err)
+			}
+
+			// Respond
+			_, err = conn.Write([]byte("HTTP/1.1 418 Teapot\r\n\r\n"))
+			if err != nil {
+				t.Error(err)
+			}
+
+			// Forcefully close connection
+			err = conn.(*net.TCPConn).SetLinger(0)
+			if err != nil {
+				t.Error(err)
+			}
+			conn.Close()
+		}
+	}()
+
+	svrUrl := "http://" + srv.Addr().String()
+	client := HostClient{Addr: srv.Addr().String()}
+
+	for i := 0; i < 100; i++ {
+		req := AcquireRequest()
+		defer ReleaseRequest(req)
+		resp := AcquireResponse()
+		defer ReleaseResponse(resp)
+
+		req.Header.SetMethod("POST")
+		req.SetBodyStream(strings.NewReader(payload), len(payload))
+		req.SetRequestURI(svrUrl)
+
+		err = client.Do(req, resp)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if expectedStatus != resp.StatusCode() {
+			t.Fatalf("Expected %d status code, but got %d", expectedStatus, resp.StatusCode())
+		}
+	}
+}
+
+// See issue #1232
+func TestRstConnClosedWithoutResponse(t *testing.T) {
+	const payload = "payload"
+
+	srv, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer srv.Close()
+
+	go func() {
+		for {
+			conn, err := srv.Accept()
+			if err != nil {
+				return
+			}
+
+			// Read at least one byte of the header
+			// Otherwise we would have an unsolicited response
+			_, err = ioutil.ReadAll(io.LimitReader(conn, 1))
+			if err != nil {
+				t.Error(err)
+			}
+
+			// Respond with incomplete header
+			_, err = conn.Write([]byte("Http"))
+			if err != nil {
+				t.Error(err)
+			}
+
+			// Forcefully close connection
+			err = conn.(*net.TCPConn).SetLinger(0)
+			if err != nil {
+				t.Error(err)
+			}
+			conn.Close()
+		}
+	}()
+
+	svrUrl := "http://" + srv.Addr().String()
+	client := HostClient{Addr: srv.Addr().String()}
+
+	for i := 0; i < 100; i++ {
+		req := AcquireRequest()
+		defer ReleaseRequest(req)
+		resp := AcquireResponse()
+		defer ReleaseResponse(resp)
+
+		req.Header.SetMethod("POST")
+		req.SetBodyStream(strings.NewReader(payload), len(payload))
+		req.SetRequestURI(svrUrl)
+
+		err = client.Do(req, resp)
+
+		if !isConnectionReset(err) {
+			t.Fatal("Expected connection reset error")
+		}
+	}
+}