fix: answer HEAD and */* page requests under vite dev

.changeset/dev-page-request-head-accept.md

@@ -0,0 +1,5 @@
+---
+'@solidjs/vite-plugin': patch
+---
+
+Under `vite dev`, pages now answer HEAD requests, and GET requests with `Accept: */*` or no Accept, the way production does. Before, these got Vite's 404. The page-request test now matches Vite's own HTML fallback.

examples/start-ssr/test/run.mjs

@@ -552,6 +552,33 @@ async function runHttpChecks(mode, origin) {
     'post-flush redirect emits the script fallback',
     post.html.includes('window.location') && post.html.includes('/redirected-target'),
   );
+
+  // Pages answer what Vite's HTML fallback counts as navigations, as in
+  // production: HEAD, a `*/*` GET (curl, fetch()), a GET with no Accept.
+  const head = await rawRequest(origin + '/', { method: 'HEAD' });
+  record(
+    mode,
+    'http',
+    'HEAD answers like GET',
+    head.status === 200 && head.text === '',
+    `status ${head.status}`,
+  );
+  const anyType = await rawRequest(origin + '/', { headers: { accept: '*/*' } });
+  record(
+    mode,
+    'http',
+    'GET accepting */* renders the page',
+    anyType.status === 200 && anyType.text.includes('SSR Start Mode'),
+    `status ${anyType.status}`,
+  );
+  const noAccept = await rawRequest(origin + '/');
+  record(
+    mode,
+    'http',
+    'GET without Accept renders the page',
+    noAccept.status === 200 && noAccept.text.includes('SSR Start Mode'),
+    `status ${noAccept.status}`,
+  );
 }
 
 // Lazy asset-key checks (the /lazy-assets surface, src/App.tsx): a
@@ -1969,13 +1996,19 @@ async function runEndpointMode() {
       functionId ? `got ${JSON.stringify(customText)}` : 'could not extract function id',
     );
 
-    const fallback = await fetch(`${origin}/_server/${encodeURIComponent(functionId || '')}`);
+    const fallback = functionId
+      ? await fetch(
+          `${origin}/_server/${encodeURIComponent(functionId)}?args=${encodeURIComponent('["endpoint"]')}`,
+          { method: 'POST' },
+        )
+      : null;
+    const fallbackText = fallback ? await fallback.text() : '';
     record(
       mode,
       'rpc',
       'default endpoint no longer handled',
-      fallback.status !== 200,
-      `status ${fallback.status}`,
+      !!fallback && fallbackText !== 'hello endpoint from the server',
+      fallback ? `status ${fallback.status}` : 'could not extract function id',
     );
   } catch (e) {
     record(

src/ssr/index.ts

@@ -1949,8 +1949,14 @@ export function startServe(
           server.middlewares.use((req, res, next) => {
             const url = new URL(req.url || '/', 'http://localhost');
             if (url.pathname.startsWith('/@')) return next();
-            const accept = req.headers.accept || '';
-            const pageRequest = req.method === 'GET' && accept.includes('text/html');
+            // Vite's own HTML-fallback test: a GET or HEAD accepting HTML by
+            // name, via `*/*`, or with no Accept (curl, monitors). Production
+            // renders all of these; anything narrower 404s in dev only.
+            const accept = req.headers.accept;
+            const pageRequest =
+              (req.method === 'GET' || req.method === 'HEAD') &&
+              url.pathname !== '/favicon.ico' &&
+              (!accept || accept.includes('text/html') || accept.includes('*/*'));
             // Production dispatches every request through the handler, so
             // dev must too or API routes and no-JS form POSTs served by
             // `start.middleware` are unreachable under `vite dev`. Without