fix(dev): skip sending headers if they are already sent

Author: danielroe

packages/nuxi/src/commands/dev.ts

@@ -229,6 +229,13 @@ async function createDevHandler(cwd: string, nuxtOptions: NuxtOptions, listenOpt
     },
     // Loading handler
     async (req, res) => {
+      if (res.headersSent) {
+        if (!res.writableEnded) {
+          res.end()
+        }
+        return
+      }
+
       res.statusCode = 503
       res.setHeader('Content-Type', 'text/html')
       res.setHeader('Cache-Control', 'no-store')

packages/nuxi/src/dev/error.ts

@@ -2,6 +2,13 @@ import type { IncomingMessage, ServerResponse } from 'node:http'
 import { Youch } from 'youch'
 
 export async function renderError(req: IncomingMessage, res: ServerResponse, error: unknown) {
+  if (res.headersSent) {
+    if (!res.writableEnded) {
+      res.end()
+    }
+    return
+  }
+
   const youch = new Youch()
   res.statusCode = 500
   res.setHeader('Content-Type', 'text/html')

packages/nuxi/src/dev/fetch.ts

@@ -185,7 +185,15 @@ async function sendWebResponse(res: ServerResponse, webResponse: Response | Node
   if (webResponse.body) {
     // handle node readable stream (from Windows named pipe fetch)
     if (webResponse.body instanceof Readable) {
-      await pipeline(webResponse.body, res, { end: true })
+      try {
+        await pipeline(webResponse.body, res, { end: true })
+      }
+      catch (error) {
+        if (!res.writableEnded) {
+          res.end()
+        }
+        throw error
+      }
       return
     }
 
@@ -202,6 +210,14 @@ async function sendWebResponse(res: ServerResponse, webResponse: Response | Node
         }
       }
     }
+    catch (error) {
+      // If streaming fails, clean up and end the response
+      reader.releaseLock()
+      if (!res.writableEnded) {
+        res.end()
+      }
+      throw error
+    }
     finally {
       reader.releaseLock()
     }

packages/nuxi/src/dev/utils.ts

@@ -159,6 +159,13 @@ export class NuxtDevServer extends EventEmitter<DevServerEventMap> {
   }
 
   async _renderLoadingScreen(req: IncomingMessage, res: ServerResponse) {
+    if (res.headersSent) {
+      if (!res.writableEnded) {
+        res.end()
+      }
+      return
+    }
+
     res.statusCode = 503
     res.setHeader('Content-Type', 'text/html')
     const loadingTemplate = this.options.loadingTemplate