fix test

Author: wxiaoguang

modules/markup/internal/finalprocessor.go

@@ -45,8 +45,10 @@ func (p *finalProcessor) Close() error {
 	} else {
 		part1, part2 = nil, buf
 	}
-	if _, err := p.output.Write(part1); err != nil {
-		return err
+	if len(part1) > 0 {
+		if _, err := p.output.Write(part1); err != nil {
+			return err
+		}
 	}
 	if _, err := io.WriteString(p.output, string(p.extraHeadHTML)); err != nil {
 		return err

tests/integration/markup_external_test.go

@@ -68,14 +68,15 @@ func TestExternalMarkupRenderer(t *testing.T) {
 		assert.Equal(t, "text/html; charset=utf-8", resp.Header().Get("Content-Type"))
 		doc := NewHTMLParser(t, resp.Body)
 		iframe := doc.Find("iframe")
-		assert.Equal(t, "/user30/renderer/render/branch/master/README.html", iframe.AttrOr("src", ""))
+		assert.Empty(t, iframe.AttrOr("src", "")) // src should be empty, "data-src" is used instead
+		assert.Equal(t, "/user30/renderer/render/branch/master/README.html", iframe.AttrOr("data-src", ""))
 
 		req = NewRequest(t, "GET", "/user30/renderer/render/branch/master/README.html")
 		resp = MakeRequest(t, req, http.StatusOK)
 		assert.Equal(t, "text/html; charset=utf-8", resp.Header().Get("Content-Type"))
 		bs, err := io.ReadAll(resp.Body)
 		assert.NoError(t, err)
 		assert.Equal(t, "frame-src 'self'; sandbox allow-scripts allow-popups", resp.Header().Get("Content-Security-Policy"))
-		assert.Equal(t, "<div>\n\ttest external renderer\n</div>\n", string(bs))
+		assert.Equal(t, "<script src=\"/assets/js/external-render-iframe.js\"></script><link rel=\"stylesheet\" href=\"/assets/css/external-render-iframe.css\"><div>\n\ttest external renderer\n</div>\n", string(bs))
 	})
 }

web_src/js/standalone/external-render-iframe.ts

@@ -10,14 +10,15 @@ RENDER_COMMAND = `echo '<div style="width: 100%; height: 2000px; border: 10px so
 
 function mainExternalRenderIframe() {
   const u = new URL(window.location.href);
-  const fn = () => window.parent.postMessage({
+  // iframe is in different origin, so we need to use postMessage to communicate height changes
+  const updateIframeHeight = () => window.parent.postMessage({
     giteaIframeCmd: 'resize',
     giteaIframeId: u.searchParams.get('gitea-iframe-id'),
     giteaIframeHeight: document.documentElement.scrollHeight,
   }, '*');
-  fn();
-  window.addEventListener('DOMContentLoaded', fn);
-  setInterval(fn, 1000);
+  updateIframeHeight();
+  window.addEventListener('DOMContentLoaded', updateIframeHeight);
+  setInterval(updateIframeHeight, 1000); // the easiest way to handle dynamic content changes and easy to debug, can be fine-tuned in the future
 
   // make all absolute links open in new window (otherwise they would be blocked by all parents' frame-src)
   document.body.addEventListener('click', (e) => {