http: close the connection after sending a body without declared length

Previously, if you removed both content-length and transfer-encoding
headers, the connection would still be kept-alive by default. This isn't
helpful, because without those headers, the only way the client knows
when the body is completed is when the connection closes.

See https://www.rfc-editor.org/rfc/rfc7230#section-3.3.3 for more
details on this message body handling logic (this is case 7).

This meant that in effect, if you removed both headers every response
came with a 5 second delay at the end (the default KA timeout) before
the client could process it. Now, if you remove both headers the
connection closes automatically immediately, so the client knows that
it has received the whole message body.

PR-URL: https://github.com/nodejs/node/pull/46333
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Paolo Insogna <paolo@cowtech.it>

lib/_http_outgoing.js

@@ -548,6 +548,10 @@ function _storeHeader(firstLine, headers) {
       // Transfer-Encoding are removed by the user.
       // See: test/parallel/test-http-remove-header-stays-removed.js
       debug('Both Content-Length and Transfer-Encoding are removed');
+
+      // We can't keep alive in this case, because with no header info the body
+      // is defined as all data until the connection is closed.
+      this._last = true;
     }
   }
 

test/parallel/test-http-remove-header-stays-removed.js

@@ -37,8 +37,6 @@ const server = http.createServer(function(request, response) {
   response.setHeader('date', 'coffee o clock');
 
   response.end('beep boop\n');
-
-  this.close();
 });
 
 let response = '';
@@ -57,5 +55,12 @@ server.listen(0, function() {
     res.on('data', function(chunk) {
       response += chunk;
     });
+
+    setTimeout(function() {
+      // The socket should be closed immediately, with no keep-alive, because
+      // no content-length or transfer-encoding are used:
+      assert.strictEqual(res.socket.closed, true);
+      server.close();
+    }, 10);
   });
 });