refactor: dedupe canvas lowercase helpers

src/agents/pi-embedded-runner/cache-ttl.ts

@@ -1,5 +1,8 @@
 import { resolveProviderCacheTtlEligibility } from "../../plugins/provider-runtime.js";
-import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
+import {
+  normalizeLowercaseStringOrEmpty,
+  normalizeOptionalLowercaseString,
+} from "../../shared/string-coerce.js";
 import { isAnthropicFamilyCacheTtlEligible } from "./anthropic-family-cache-semantics.js";
 import { isGooglePromptCacheEligible } from "./prompt-cache-retention.js";
 
@@ -46,7 +49,7 @@ export function isCacheTtlEligibleProvider(
 }
 
 function normalizeCacheTtlKey(value: string | undefined): string | undefined {
-  return value?.trim().toLowerCase();
+  return normalizeOptionalLowercaseString(value);
 }
 
 function matchesCacheTtlContext(

src/canvas-host/a2ui.ts

@@ -3,6 +3,7 @@ import type { IncomingMessage, ServerResponse } from "node:http";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
 import { detectMime } from "../media/mime.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { resolveFileWithinRoot } from "./file-resolver.js";
 
 export const A2UI_PATH = "/__openclaw__/a2ui";
@@ -132,7 +133,7 @@ export function injectCanvasLiveReload(html: string): string {
 </script>
 `.trim();
 
-  const idx = html.toLowerCase().lastIndexOf("</body>");
+  const idx = normalizeLowercaseStringOrEmpty(html).lastIndexOf("</body>");
   if (idx >= 0) {
     return `${html.slice(0, idx)}\n${snippet}\n${html.slice(idx)}`;
   }
@@ -180,7 +181,7 @@ export async function handleA2uiHttpRequest(
   }
 
   try {
-    const lower = result.realPath.toLowerCase();
+    const lower = normalizeLowercaseStringOrEmpty(result.realPath);
     const mime =
       lower.endsWith(".html") || lower.endsWith(".htm")
         ? "text/html"

src/canvas-host/server.ts

@@ -15,6 +15,7 @@ import { resolveStateDir } from "../config/paths.js";
 import { isTruthyEnvValue } from "../infra/env.js";
 import { detectMime } from "../media/mime.js";
 import type { RuntimeEnv } from "../runtime.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { ensureDir, resolveUserPath } from "../utils.js";
 import {
   CANVAS_HOST_PATH,
@@ -393,7 +394,7 @@ export async function createCanvasHostHandler(
         await handle.close().catch(() => {});
       }
 
-      const lower = realPath.toLowerCase();
+      const lower = normalizeLowercaseStringOrEmpty(realPath);
       const mime =
         lower.endsWith(".html") || lower.endsWith(".htm")
           ? "text/html"
@@ -464,7 +465,7 @@ export async function startCanvasHost(opts: CanvasHostServerOpts): Promise<Canva
 
   const bindHost = opts.listenHost?.trim() || "127.0.0.1";
   const server: Server = http.createServer((req, res) => {
-    if (String(req.headers.upgrade ?? "").toLowerCase() === "websocket") {
+    if (normalizeLowercaseStringOrEmpty(req.headers.upgrade ?? "") === "websocket") {
       return;
     }
     void (async () => {

src/test-utils/mock-http-response.ts

@@ -1,4 +1,5 @@
 import type { ServerResponse } from "node:http";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 
 export function createMockServerResponse(): ServerResponse & { body?: string } {
   const headers: Record<string, string> = {};
@@ -13,10 +14,10 @@ export function createMockServerResponse(): ServerResponse & { body?: string } {
     headersSent: false,
     statusCode: 200,
     setHeader: (key: string, value: string) => {
-      headers[key.toLowerCase()] = value;
+      headers[normalizeLowercaseStringOrEmpty(key)] = value;
       return res;
     },
-    getHeader: (key: string) => headers[key.toLowerCase()],
+    getHeader: (key: string) => headers[normalizeLowercaseStringOrEmpty(key)],
     end: (body?: string) => {
       res.headersSent = true;
       res.body = body;