fix: handle ping requests before they reach user middleware

vitejs · May 8, 2023 · 5d57541 · 5d57541
1 parent c63ba3f
commit 5d57541
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diff --git a/packages/vite/src/client/client.ts b/packages/vite/src/client/client.ts
@@ -321,6 +321,11 @@ async function waitForSuccessfulPing(
     try {
       await fetch(`${pingHostProtocol}://${hostAndPath}`, {
         mode: 'no-cors',
+        headers: {
+          // Custom headers won't be included in a request with no-cors so (ab)use one of the
+          // safelisted headers to identify the ping request
+          Accept: 'text/x-vite-ping',
+        },
       })
       return true
     } catch {}

diff --git a/packages/vite/src/node/server/index.ts b/packages/vite/src/node/server/index.ts
@@ -608,6 +608,15 @@ export async function _createServer(
   // open in editor support
   middlewares.use('/__open-in-editor', launchEditorMiddleware())
 
+  // ping request handler
+  middlewares.use((req, res, next) => {
+    if (req.headers['accept'] === 'text/x-vite-ping') {
+      res.writeHead(204).end()
+    } else {
+      next()
+    }
+  })
+
   // serve static files under /public
   // this applies before the transform middleware so that these files are served
   // as-is without transforms.