fix transfer-encoding for all responses

- proxied response transfer-encoding is never relevant for the client response
- need to reimplement transfer-encoding when proxying directly to the socket instead of the Response object

Author: minrk

lib/http-proxy/passes/web-outgoing.ts

@@ -27,14 +27,13 @@ export interface EditableResponse {
 
 // If is a HTTP 1.0 request, remove chunk headers
 export function removeChunked(
-  req: Request,
+  _req: Request,
   _res: EditableResponse,
   // Response object from the proxy request
   proxyRes: ProxyResponse,
 ) {
-  if (req.httpVersion === "1.0") {
-    delete proxyRes.headers["transfer-encoding"];
-  }
+  // transfer-encoding is hop-by-hop, don't preserve it across proxy hops
+  delete proxyRes.headers["transfer-encoding"];
 }
 
 // If is a HTTP 1.0 request, set the correct connection header

lib/http-proxy/passes/ws-incoming.ts

@@ -257,16 +257,36 @@ export function stream(
       // note: none of these return anything
       pass(req, res as EditableResponse, proxyRes, options as NormalizedServerOptions & { target: NormalizeProxyTarget<ProxyTarget> });
     }
-    // avoid Invalid character error in chunk size
-    delete res.headers['transfer-encoding'];
+
+    // implement HTTP/1.1 chunked transfer unless content-length is defined
+    // matches proxyRes.pipe(res) behavior,
+    // but we are piping directly to the socket instead, so it's our job.
+    let writeChunk = (chunk: Buffer | string) => {
+      socket.write(chunk);
+    }
+    if (req.httpVersion === "1.1" && proxyRes.headers["content-length"] === undefined) {
+      res.headers["transfer-encoding"] = "chunked";
+      writeChunk = (chunk: Buffer | string) => {
+        socket.write(chunk.length.toString(16));
+        socket.write("\r\n");
+        socket.write(chunk);
+        socket.write("\r\n");
+      }
+    }
 
     const proxyHead = createHttpHeader(
       `HTTP/${req.httpVersion} ${proxyRes.statusCode} ${proxyRes.statusMessage}`,
       res.headers,
     );
     if (!socket.destroyed) {
       socket.write(proxyHead);
-      proxyRes.pipe(socket);
+      proxyRes.on("data", (chunk) => {
+        writeChunk(chunk);
+      })
+      proxyRes.on("end", () => {
+        writeChunk("");
+        socket.destroySoon();
+      })
     } else {
       // make sure response is consumed
       proxyRes.resume();