perf(platform-server): speed up resolution of base (#61392)

crisbeto · thePunderWoman · commit fb65ad157c7d · 2025-05-16T09:03:38.000Z
The `getBaseHref` method is called several times per request and currently queries through the entire document. We can speed it up by taking advantage of the fact that the `<base>` can only be a direct child of the `<head>` and is usually defined towards the beginning. Below are some benchmarks for a "Hello world" app before and after this change. ### Before: ``` Running 60s test @ http://localhost:4202 100 connections with 10 pipelining factor ┌─────────┬────────┬────────┬────────┬────────┬───────────┬──────────┬─────────┐ │ Stat │ 2.5% │ 50% │ 97.5% │ 99% │ Avg │ Stdev │ Max │ ├─────────┼────────┼────────┼────────┼────────┼───────────┼──────────┼─────────┤ │ Latency │ 568 ms │ 853 ms │ 901 ms │ 904 ms │ 866.58 ms │ 437.6 ms │ 9915 ms │ └─────────┴────────┴────────┴────────┴────────┴───────────┴──────────┴─────────┘ ┌───────────┬─────────┬─────────┬─────────┬─────────┬─────────┬─────────┬─────────┐ │ Stat │ 1% │ 2.5% │ 50% │ 97.5% │ Avg │ Stdev │ Min │ ├───────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┤ │ Req/Sec │ 490 │ 826 │ 1,006 │ 1,643 │ 1,129.3 │ 234.69 │ 490 │ ├───────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┼─────────┤ │ Bytes/Sec │ 10.4 MB │ 17.4 MB │ 21.3 MB │ 34.7 MB │ 23.9 MB │ 4.96 MB │ 10.3 MB │ └───────────┴─────────┴─────────┴─────────┴─────────┴─────────┴─────────┴─────────┘ Req/Bytes counts sampled once per second. # of samples: 60 69k requests in 60.04s, 1.43 GB read 90 errors (90 timeouts) ``` ### After ``` Running 60s test @ http://localhost:4202 100 connections with 10 pipelining factor ┌─────────┬────────┬────────┬────────┬─────────┬───────────┬───────────┬─────────┐ │ Stat │ 2.5% │ 50% │ 97.5% │ 99% │ Avg │ Stdev │ Max │ ├─────────┼────────┼────────┼────────┼─────────┼───────────┼───────────┼─────────┤ │ Latency │ 471 ms │ 831 ms │ 889 ms │ 1668 ms │ 835.91 ms │ 467.89 ms │ 9720 ms │ └─────────┴────────┴────────┴────────┴─────────┴───────────┴───────────┴─────────┘ ┌───────────┬─────────┬─────────┬─────────┬─────────┬──────────┬────────┬─────────┐ │ Stat │ 1% │ 2.5% │ 50% │ 97.5% │ Avg │ Stdev │ Min │ ├───────────┼─────────┼─────────┼─────────┼─────────┼──────────┼────────┼─────────┤ │ Req/Sec │ 390 │ 860 │ 1,145 │ 1,572 │ 1,156.77 │ 222.65 │ 390 │ ├───────────┼─────────┼─────────┼─────────┼─────────┼──────────┼────────┼─────────┤ │ Bytes/Sec │ 8.24 MB │ 18.2 MB │ 24.2 MB │ 33.2 MB │ 24.4 MB │ 4.7 MB │ 8.24 MB │ └───────────┴─────────┴─────────┴─────────┴─────────┴──────────┴────────┴─────────┘ Req/Bytes counts sampled once per second. # of samples: 60 71k requests in 60.03s, 1.47 GB read 140 errors (140 timeouts) ``` PR Close #61392
diff --git a/packages/platform-browser/src/browser/browser_adapter.ts b/packages/platform-browser/src/browser/browser_adapter.ts
@@ -86,7 +86,7 @@ export class BrowserDomAdapter extends DomAdapter {
 
 let baseElement: HTMLElement | null = null;
 function getBaseElementHref(): string | null {
-  baseElement = baseElement || document.querySelector('base');
+  baseElement = baseElement || document.head.querySelector('base');
   return baseElement ? baseElement.getAttribute('href') : null;
 }
 
diff --git a/packages/platform-server/src/domino_adapter.ts b/packages/platform-server/src/domino_adapter.ts
@@ -79,8 +79,24 @@ export class DominoAdapter extends BrowserDomAdapter {
   }
 
   override getBaseHref(doc: Document): string {
-    // TODO(alxhub): Need relative path logic from BrowserDomAdapter here?
-    return doc.documentElement!.querySelector('base')?.getAttribute('href') || '';
+    const length = doc.head.children.length;
+
+    // The `<base>` can only be a direct child of `<head>` so we can save some
+    // execution time by looking through them directly instead of querying for it.
+    // See: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Elements/base
+    // Note that we can't cache the `href` value itself, because this method gets called with a
+    // different document every time which means that in theory the value can be different too.
+    for (let i = 0; i < length; i++) {
+      const child = doc.head.children[i];
+
+      // Tag names are always uppercase for HTML nodes.
+      if (child.tagName === 'BASE') {
+        // TODO(alxhub): Need relative path logic from BrowserDomAdapter here?
+        return child.getAttribute('href') || '';
+      }
+    }
+
+    return '';
   }
 
   override dispatchEvent(el: Node, evt: any) {

Original file line number	Diff line number	Diff line change
`@@ -86,7 +86,7 @@ export class BrowserDomAdapter extends DomAdapter {`
`86`	`86`
`87`	`87`	`let baseElement: HTMLElement \| null = null;`
`88`	`88`	`function getBaseElementHref(): string \| null {`
`89`		`- baseElement = baseElement \|\| document.querySelector('base');`
	`89`	`+ baseElement = baseElement \|\| document.head.querySelector('base');`
`90`	`90`	`return baseElement ? baseElement.getAttribute('href') : null;`
`91`	`91`	`}`
`92`	`92`