fix gzip not sending response code for no content responses (404, 301…

…/302 redirects etc)

middleware/compress.go

@@ -107,10 +107,16 @@ func GzipWithConfig(config GzipConfig) echo.MiddlewareFunc {
 
 				grw := &gzipResponseWriter{Writer: w, ResponseWriter: rw, minLength: config.MinLength, buffer: buf}
 				defer func() {
+					// There are different reasons for cases when we have not yet written response to the client and now need to do so.
+					// a) handler response had only response code and no response body (ala 404 or redirects etc). Response code need to be written now.
+					// b) body is shorter than our minimum length threshold and being buffered currently and needs to be written
 					if !grw.wroteBody {
 						if res.Header().Get(echo.HeaderContentEncoding) == gzipScheme {
 							res.Header().Del(echo.HeaderContentEncoding)
 						}
+						if grw.wroteHeader {
+							rw.WriteHeader(grw.code)
+						}
 						// We have to reset response to it's pristine state when
 						// nothing is written to body or error is returned.
 						// See issue #424, #407.

middleware/compress_test.go

@@ -89,8 +89,6 @@ func TestGzip(t *testing.T) {
 }
 
 func TestGzipWithMinLength(t *testing.T) {
-	assert := assert.New(t)
-
 	e := echo.New()
 	// Minimal response length
 	e.Use(GzipWithConfig(GzipConfig{MinLength: 10}))
@@ -103,19 +101,17 @@ func TestGzipWithMinLength(t *testing.T) {
 	req.Header.Set(echo.HeaderAcceptEncoding, gzipScheme)
 	rec := httptest.NewRecorder()
 	e.ServeHTTP(rec, req)
-	assert.Equal(gzipScheme, rec.Header().Get(echo.HeaderContentEncoding))
+	assert.Equal(t, gzipScheme, rec.Header().Get(echo.HeaderContentEncoding))
 	r, err := gzip.NewReader(rec.Body)
-	if assert.NoError(err) {
+	if assert.NoError(t, err) {
 		buf := new(bytes.Buffer)
 		defer r.Close()
 		buf.ReadFrom(r)
-		assert.Equal("foobarfoobar", buf.String())
+		assert.Equal(t, "foobarfoobar", buf.String())
 	}
 }
 
 func TestGzipWithMinLengthTooShort(t *testing.T) {
-	assert := assert.New(t)
-
 	e := echo.New()
 	// Minimal response length
 	e.Use(GzipWithConfig(GzipConfig{MinLength: 10}))
@@ -127,13 +123,29 @@ func TestGzipWithMinLengthTooShort(t *testing.T) {
 	req.Header.Set(echo.HeaderAcceptEncoding, gzipScheme)
 	rec := httptest.NewRecorder()
 	e.ServeHTTP(rec, req)
-	assert.Equal("", rec.Header().Get(echo.HeaderContentEncoding))
-	assert.Contains(rec.Body.String(), "test")
+	assert.Equal(t, "", rec.Header().Get(echo.HeaderContentEncoding))
+	assert.Contains(t, rec.Body.String(), "test")
 }
 
-func TestGzipWithMinLengthChunked(t *testing.T) {
-	assert := assert.New(t)
+func TestGzipWithResponseWithoutBody(t *testing.T) {
+	e := echo.New()
+
+	e.Use(Gzip())
+	e.GET("/", func(c echo.Context) error {
+		return c.Redirect(http.StatusMovedPermanently, "http://localhost")
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set(echo.HeaderAcceptEncoding, gzipScheme)
+	rec := httptest.NewRecorder()
 
+	e.ServeHTTP(rec, req)
+
+	assert.Equal(t, http.StatusMovedPermanently, rec.Code)
+	assert.Equal(t, "", rec.Header().Get(echo.HeaderContentEncoding))
+}
+
+func TestGzipWithMinLengthChunked(t *testing.T) {
 	e := echo.New()
 
 	// Gzip chunked
@@ -155,36 +167,36 @@ func TestGzipWithMinLengthChunked(t *testing.T) {
 		c.Response().Flush()
 
 		// Read the first part of the data
-		assert.True(rec.Flushed)
-		assert.Equal(gzipScheme, rec.Header().Get(echo.HeaderContentEncoding))
+		assert.True(t, rec.Flushed)
+		assert.Equal(t, gzipScheme, rec.Header().Get(echo.HeaderContentEncoding))
 
 		var err error
 		r, err = gzip.NewReader(rec.Body)
-		assert.NoError(err)
+		assert.NoError(t, err)
 
 		_, err = io.ReadFull(r, chunkBuf)
-		assert.NoError(err)
-		assert.Equal("test\n", string(chunkBuf))
+		assert.NoError(t, err)
+		assert.Equal(t, "test\n", string(chunkBuf))
 
 		// Write and flush the second part of the data
 		c.Response().Write([]byte("test\n"))
 		c.Response().Flush()
 
 		_, err = io.ReadFull(r, chunkBuf)
-		assert.NoError(err)
-		assert.Equal("test\n", string(chunkBuf))
+		assert.NoError(t, err)
+		assert.Equal(t, "test\n", string(chunkBuf))
 
 		// Write the final part of the data and return
 		c.Response().Write([]byte("test"))
 		return nil
 	})(c)
 
-	assert.NotNil(r)
+	assert.NotNil(t, r)
 
 	buf := new(bytes.Buffer)
 
 	buf.ReadFrom(r)
-	assert.Equal("test", buf.String())
+	assert.Equal(t, "test", buf.String())
 
 	r.Close()
 }