Apollo Client sends duplicate requests

Intended outcome: I am trying to log response times in my Express server.

Right now, while I’m debugging, my code looks like this.

app.use(
  responseTime((req: express.Request, res, time) => {
    if (req.method === "OPTIONS") {
      return;
    }
    console.log(
      `response time (seconds) for ${req.get("origin")} ${req.method} ${
        req.originalUrl
      } ${req.body?.operationName}`,
      req.headers,
      time / 1000
    );
  })
);

Actual outcome: For every GraphQL query, I see logs for two requests.

I know these are being sent by Apollo Client because I added a dummy header (foo).

Here are a couple of example logs that occur when I refresh a page.

response time (seconds) for undefined POST /graphql MyQueryName {
  accept: '*/*',
  'content-type': 'application/json',
  foo: 'client',
  'content-length': '547',
  'user-agent': 'node-fetch/1.0 (+https://github.com/bitinn/node-fetch)',
  'accept-encoding': 'gzip,deflate',
  connection: 'close',
  host: 'localhost:4000'
} 0.0009104899999999999
response time (seconds) for http://localhost:3000 POST /graphql MyQueryName {
  host: 'localhost:4000',
  connection: 'keep-alive',
  'content-length': '547',
  pragma: 'no-cache',
  'cache-control': 'no-cache',
  accept: '*/*',
  foo: 'client',
  'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.96 Safari/537.36',
  'content-type': 'application/json',
  origin: 'http://localhost:3000',
  'sec-fetch-site': 'same-site',
  'sec-fetch-mode': 'cors',
  'sec-fetch-dest': 'empty',
  referer: 'http://localhost:3000/',
  'accept-encoding': 'gzip, deflate, br',
  'accept-language': 'en-US,en;q=0.9',
  cookie: '...'
} 0.007458307999999999

On the client side, I’m using createUploadLink. Using createHttpLink doesn’t fix it.

How to reproduce the issue: Slightly cumbersome to repro because you need client + server code. I can add this later if needed,

Versions

System:
  OS: macOS 10.15.2
Binaries:
  Node: 12.18.2 - /usr/local/bin/node
  Yarn: 1.22.4 - /usr/local/bin/yarn
  npm: 6.14.5 - /usr/local/bin/npm
Browsers:
  Chrome: 88.0.4324.182
  Firefox: 79.0
  Safari: 13.0.4
npmPackages:
  @apollo/client: ^3.3.5 => 3.3.5
  apollo-upload-client: ^14.1.3 => 14.1.3

[john1625b]

This recently closed issue might help to explain why we expect the duplicate calls.

@jcreighton Hi, sorry but I can’t understand what that linked issue is trying to say. Could you explain it simply why apollo does 2 duplicate network requests by default when using network-only

[jcreighton]

Closing this as we don’t have enough information to take action. If it’s still an issue and you can provide a reproduction, I’ll be happy to re-open the issue.