Google Cloud Functions 标头响应

Question

I am executing a GCF triggered by an Http Request, and I only need to receive a custom message, however, I receive all of this headers:

HTTP/1.1 200 OK
Server: nginx
Content-Type: application/json; charset=utf-8
x-powered-by: Express
cache-control: private
Strict-Transport-Security: max-age=31556926; includeSubDomains; preload
etag: W/"19-7046833f"
function-execution-id: nx88bs3fra23
x-cloud-trace-context: 302401ba6a3c3d461c32dc7e4825c54d;o=1, 302401ba6a3c3d461c32dc7e4825c54d
Content-Length: 25
Accept-Ranges: bytes
Date: Wed, 05 Jul 2017 01:48:23 GMT
Via: 1.1 varnish
Connection: keep-alive
X-Served-By: cache-lax8651-LAX
X-Cache: MISS
X-Cache-Hits: 0
X-Timer: S1499219281.929840,VS0,VE22189

I don't need to use any of the headers because I am doing a request from a 3G module, not a web browser. The code used to receive this is the following:

'use strict';
exports.myfunction = functions.https.onRequest((req, res) => {
  admin.database().ref('/root').once('child_changed', (snapshot) =>{
    res.send(snapshot.val());
  });
});

Is there any way to remove these headers from the response? I have been reading the response documentation , and I found the res.set(field [, value]) method.

Do you know if it is possible to remove the automatic headers sent by the server?

Answer 1

I just tried a Hello World Cloud Functions example and based on that, the following response headers are added by Google Cloud Functions:

Content-Length: 12
Date: Sat, 08 Jul 2017 12:12:12 GMT
ETag: W/"c-1a2b3c4d"
Server: Foo
content-type: text/html; charset=utf-8
function-execution-id: SOME_EXECUTION_ID
x-cloud-trace-context: SOME_CONTEXT_1;o=1
x-cloud-trace-context: SOME_CONTEXT_2
x-powered-by: Express

There is no way to remove any of these headers from the Google Cloud Functions side. Some of the headers in your response seem to be coming from a Varnish Cache, so unless you plan to remove Varnish caching I guess you will not be able to remove those too.

The overhead of the response headers is quite small (<1kB in your example) and I would rather not worry about them (even over 3G).