Merge branch 'gzip-content-type' into 'master'

Prevent wrong mimetype being set for GZipped files with unknown file extension

Closes #181

See merge request gitlab-org/gitlab-pages!122

2 files changed, 63 insertions, 29 deletions

diff --git a/internal/domain/domain.go b/internal/domain/domain.go
index 2c4f4e29..64311e65 100644
--- a/internal/domain/domain.go
+++ b/internal/domain/domain.go
@@ -230,6 +230,26 @@ func (d *D) HasProject(r *http.Request) bool {
 	return false
 }
 
+// Detect file's content-type either by extension or mime-sniffing.
+// Implementation is adapted from Golang's `http.serveContent()`
+// See https://github.com/golang/go/blob/902fc114272978a40d2e65c2510a18e870077559/src/net/http/fs.go#L194
+func (d *D) detectContentType(path string) (string, error) {
+	contentType := mime.TypeByExtension(filepath.Ext(path))
+	if contentType == "" {
+		var buf [512]byte
+		file, err := os.Open(path)
+		if err != nil {
+			return "", err
+		}
+		defer file.Close()
+		// Using `io.ReadFull()` because `file.Read()` may be chunked.
+		// Ignoring errors because we don't care if the 512 bytes cannot be read.
+		n, _ := io.ReadFull(file, buf[:])
+		contentType = http.DetectContentType(buf[:n])
+	}
+	return contentType, nil
+}
+
 func (d *D) serveFile(w http.ResponseWriter, r *http.Request, origPath string) error {
 	fullPath := handleGZip(w, r, origPath)
 
@@ -250,7 +270,12 @@ func (d *D) serveFile(w http.ResponseWriter, r *http.Request, origPath string) e
 		w.Header().Set("Expires", time.Now().Add(10*time.Minute).Format(time.RFC1123))
 	}
 
-	// ServeContent sets Content-Type for us
+	contentType, err := d.detectContentType(origPath)
+	if err != nil {
+		return err
+	}
+	w.Header().Set("Content-Type", contentType)
+
 	http.ServeContent(w, r, origPath, fi.ModTime(), file)
 	return nil
 }
diff --git a/internal/domain/domain_test.go b/internal/domain/domain_test.go
index 7544f501..32bf2e3d 100644
--- a/internal/domain/domain_test.go
+++ b/internal/domain/domain_test.go
@@ -181,7 +181,7 @@ func TestIsHTTPSOnly(t *testing.T) {
 	}
 }
 
-func testHTTPGzip(t *testing.T, handler http.HandlerFunc, mode, url string, values url.Values, acceptEncoding string, str interface{}, ungzip bool) {
+func testHTTPGzip(t *testing.T, handler http.HandlerFunc, mode, url string, values url.Values, acceptEncoding string, str interface{}, contentType string, ungzip bool) {
 	w := httptest.NewRecorder()
 	req, err := http.NewRequest(mode, url+"?"+values.Encode(), nil)
 	require.NoError(t, err)
@@ -204,6 +204,8 @@ func testHTTPGzip(t *testing.T, handler http.HandlerFunc, mode, url string, valu
 	} else {
 		assert.Contains(t, w.Body.String(), str)
 	}
+
+	assert.Equal(t, contentType, w.Header().Get("Content-Type"))
 }
 
 func TestGroupServeHTTPGzip(t *testing.T) {
@@ -223,43 +225,50 @@ func TestGroupServeHTTPGzip(t *testing.T) {
 	testSet := []struct {
 		mode           string      // HTTP mode
 		url            string      // Test URL
-		params         url.Values  // Test URL params
 		acceptEncoding string      // Accept encoding header
 		body           interface{} // Expected body at above URL
-		ungzip         bool        // Do we expect the request to require unzip?
+		contentType    string      // Expected content-type
+		ungzip         bool        // Expect the response to be gzipped?
 	}{
 		// No gzip encoding requested
-		{"GET", "http://group.test.io/", nil, "", "main-dir", false},
-		{"GET", "http://group.test.io/", nil, "identity", "main-dir", false},
-		{"GET", "http://group.test.io/", nil, "gzip; q=0", "main-dir", false},
-		// gzip encoding requeste},
-		{"GET", "http://group.test.io/", nil, "*", "main-dir", true},
-		{"GET", "http://group.test.io/", nil, "identity, gzip", "main-dir", true},
-		{"GET", "http://group.test.io/", nil, "gzip", "main-dir", true},
-		{"GET", "http://group.test.io/", nil, "gzip; q=1", "main-dir", true},
-		{"GET", "http://group.test.io/", nil, "gzip; q=0.9", "main-dir", true},
-		{"GET", "http://group.test.io/", nil, "gzip, deflate", "main-dir", true},
-		{"GET", "http://group.test.io/", nil, "gzip; q=1, deflate", "main-dir", true},
-		{"GET", "http://group.test.io/", nil, "gzip; q=0.9, deflate", "main-dir", true},
+		{"GET", "/index.html", "", "main-dir", "text/html; charset=utf-8", false},
+		{"GET", "/index.html", "identity", "main-dir", "text/html; charset=utf-8", false},
+		{"GET", "/index.html", "gzip; q=0", "main-dir", "text/html; charset=utf-8", false},
+		// gzip encoding requested,
+		{"GET", "/index.html", "*", "main-dir", "text/html; charset=utf-8", true},
+		{"GET", "/index.html", "identity, gzip", "main-dir", "text/html; charset=utf-8", true},
+		{"GET", "/index.html", "gzip", "main-dir", "text/html; charset=utf-8", true},
+		{"GET", "/index.html", "gzip; q=1", "main-dir", "text/html; charset=utf-8", true},
+		{"GET", "/index.html", "gzip; q=0.9", "main-dir", "text/html; charset=utf-8", true},
+		{"GET", "/index.html", "gzip, deflate", "main-dir", "text/html; charset=utf-8", true},
+		{"GET", "/index.html", "gzip; q=1, deflate", "main-dir", "text/html; charset=utf-8", true},
+		{"GET", "/index.html", "gzip; q=0.9, deflate", "main-dir", "text/html; charset=utf-8", true},
 		// gzip encoding requested, but url does not have compressed content on disk
-		{"GET", "http://group.test.io/project2/", nil, "*", "project2-main", false},
-		{"GET", "http://group.test.io/project2/", nil, "identity, gzip", "project2-main", false},
-		{"GET", "http://group.test.io/project2/", nil, "gzip", "project2-main", false},
-		{"GET", "http://group.test.io/project2/", nil, "gzip; q=1", "project2-main", false},
-		{"GET", "http://group.test.io/project2/", nil, "gzip; q=0.9", "project2-main", false},
-		{"GET", "http://group.test.io/project2/", nil, "gzip, deflate", "project2-main", false},
-		{"GET", "http://group.test.io/project2/", nil, "gzip; q=1, deflate", "project2-main", false},
-		{"GET", "http://group.test.io/project2/", nil, "gzip; q=0.9, deflate", "project2-main", false},
+		{"GET", "/project2/index.html", "*", "project2-main", "text/html; charset=utf-8", false},
+		{"GET", "/project2/index.html", "identity, gzip", "project2-main", "text/html; charset=utf-8", false},
+		{"GET", "/project2/index.html", "gzip", "project2-main", "text/html; charset=utf-8", false},
+		{"GET", "/project2/index.html", "gzip; q=1", "project2-main", "text/html; charset=utf-8", false},
+		{"GET", "/project2/index.html", "gzip; q=0.9", "project2-main", "text/html; charset=utf-8", false},
+		{"GET", "/project2/index.html", "gzip, deflate", "project2-main", "text/html; charset=utf-8", false},
+		{"GET", "/project2/index.html", "gzip; q=1, deflate", "project2-main", "text/html; charset=utf-8", false},
+		{"GET", "/project2/index.html", "gzip; q=0.9, deflate", "project2-main", "text/html; charset=utf-8", false},
 		// malformed headers
-		{"GET", "http://group.test.io/", nil, ";; gzip", "main-dir", false},
-		{"GET", "http://group.test.io/", nil, "middle-out", "main-dir", false},
-		{"GET", "http://group.test.io/", nil, "gzip; quality=1", "main-dir", false},
+		{"GET", "/index.html", ";; gzip", "main-dir", "text/html; charset=utf-8", false},
+		{"GET", "/index.html", "middle-out", "main-dir", "text/html; charset=utf-8", false},
+		{"GET", "/index.html", "gzip; quality=1", "main-dir", "text/html; charset=utf-8", false},
 		// Symlinked .gz files are not supported
-		{"GET", "http://group.test.io/gz-symlink", nil, "*", "data", false},
+		{"GET", "/gz-symlink", "*", "data", "text/plain; charset=utf-8", false},
+		// Unknown file-extension, with text content
+		{"GET", "/text.unknown", "*", "hello", "text/plain; charset=utf-8", true},
+		{"GET", "/text-nogzip.unknown", "*", "hello", "text/plain; charset=utf-8", false},
+		// Unknown file-extension, with PNG content
+		{"GET", "/image.unknown", "*", "GIF89a", "image/gif", true},
+		{"GET", "/image-nogzip.unknown", "*", "GIF89a", "image/gif", false},
 	}
 
 	for _, tt := range testSet {
-		testHTTPGzip(t, serveFileOrNotFound(testGroup), tt.mode, tt.url, tt.params, tt.acceptEncoding, tt.body, tt.ungzip)
+		URL := "http://group.test.io" + tt.url
+		testHTTPGzip(t, serveFileOrNotFound(testGroup), tt.mode, URL, nil, tt.acceptEncoding, tt.body, tt.contentType, tt.ungzip)
 	}
 }