Issue valyala#176: reset Content-Length when compression is enabled f…

…or streamed response body

http.go

@@ -1194,9 +1194,14 @@ func (resp *Response) gzipBody(level int) error {
 		return nil
 	}
 
-	// Do not care about memory allocations here, since gzip is slow
-	// and allocates a lot of memory by itself.
 	if resp.bodyStream != nil {
+		// Reset Content-Length to -1, since it is impossible
+		// to determine body size beforehand of streamed compression.
+		// For https://github.com/valyala/fasthttp/issues/176 .
+		resp.Header.SetContentLength(-1)
+
+		// Do not care about memory allocations here, since gzip is slow
+		// and allocates a lot of memory by itself.
 		bs := resp.bodyStream
 		resp.bodyStream = NewStreamReader(func(sw *bufio.Writer) {
 			zw := acquireStacklessGzipWriter(sw, level)
@@ -1243,9 +1248,14 @@ func (resp *Response) deflateBody(level int) error {
 		return nil
 	}
 
-	// Do not care about memory allocations here, since flate is slow
-	// and allocates a lot of memory by itself.
 	if resp.bodyStream != nil {
+		// Reset Content-Length to -1, since it is impossible
+		// to determine body size beforehand of streamed compression.
+		// For https://github.com/valyala/fasthttp/issues/176 .
+		resp.Header.SetContentLength(-1)
+
+		// Do not care about memory allocations here, since flate is slow
+		// and allocates a lot of memory by itself.
 		bs := resp.bodyStream
 		resp.bodyStream = NewStreamReader(func(sw *bufio.Writer) {
 			zw := acquireStacklessDeflateWriter(sw, level)

http_test.go

@@ -12,6 +12,78 @@ import (
 	"time"
 )
 
+func TestResponseBodyStreamDeflate(t *testing.T) {
+	body := createFixedBody(1e5)
+
+	// Verifies https://github.com/valyala/fasthttp/issues/176
+	// when Content-Length is explicitly set.
+	testResponseBodyStreamDeflate(t, body, len(body))
+
+	// Verifies that 'transfer-encoding: chunked' works as expected.
+	testResponseBodyStreamDeflate(t, body, -1)
+}
+
+func TestResponseBodyStreamGzip(t *testing.T) {
+	body := createFixedBody(1e5)
+
+	// Verifies https://github.com/valyala/fasthttp/issues/176
+	// when Content-Length is explicitly set.
+	testResponseBodyStreamGzip(t, body, len(body))
+
+	// Verifies that 'transfer-encoding: chunked' works as expected.
+	testResponseBodyStreamGzip(t, body, -1)
+}
+
+func testResponseBodyStreamDeflate(t *testing.T, body []byte, bodySize int) {
+	var r Response
+	r.SetBodyStream(bytes.NewReader(body), bodySize)
+
+	w := &bytes.Buffer{}
+	bw := bufio.NewWriter(w)
+	if err := r.WriteDeflate(bw); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	var resp Response
+	br := bufio.NewReader(w)
+	if err := resp.Read(br); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	respBody, err := resp.BodyInflate()
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if !bytes.Equal(respBody, body) {
+		t.Fatalf("unexpected body: %q. Expecting %q", respBody, body)
+	}
+}
+
+func testResponseBodyStreamGzip(t *testing.T, body []byte, bodySize int) {
+	var r Response
+	r.SetBodyStream(bytes.NewReader(body), bodySize)
+
+	w := &bytes.Buffer{}
+	bw := bufio.NewWriter(w)
+	if err := r.WriteGzip(bw); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	var resp Response
+	br := bufio.NewReader(w)
+	if err := resp.Read(br); err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	respBody, err := resp.BodyGunzip()
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if !bytes.Equal(respBody, body) {
+		t.Fatalf("unexpected body: %q. Expecting %q", respBody, body)
+	}
+}
+
 func TestResponseWriteGzipNilBody(t *testing.T) {
 	var r Response
 	w := &bytes.Buffer{}