proxy.bypass return false does not work

[jsmith-sapient]

• Operating System: MacOS High Sierra
• Node Version: 11.0.0
• NPM Version: 6.4.1
• webpack Version: 4.29.5
• webpack-dev-server Version: 3.2.0

• This is a bug
• This is a modification request

Code

does not work:

// webpack.config.js

module.exports = {
  devServer: {
    proxy: {
      '**': {
        bypass(req) {
          if (!req.headers.accept.includes('application/json'))
            return false; // ← does nothing
        },
        target: `http://localhost:${yargs.proxyPort}`,
      },
    },
  },
  entry: './app',
}

does work:

// webpack.config.js

module.exports = {
  devServer: {
    proxy: {
      '**': {
        bypass(req) {
          if (!req.headers.accept.includes('application/json'))
            return req.url;
        },
        target: `http://localhost:${yargs.proxyPort}`,
      },
    },
  },
  entry: './app',
}

Expected Behaviour

Based on the vague explanation in the docs

It must return either false or a path that will be served instead of continuing to proxy the request.

I expect return false to skip the proxy

Actual Behaviour

return false does nothing.

For Bugs; How can we reproduce the behaviour?

Minimal example: https://github.com/jsmith-sapient/local-api-mocker

npm run start:dev

[alexander-akait]

Can you try return null or something else? Looks like regression in http-proxy/http-proxy-middleware

[alexander-akait]

Anyway PR welcome

[jsmith-sapient]

@evilebottnawi I tried null: No difference to false (it does nothing).

I'll try to find some time this weekend to take a look. I might be posting as @jshado1 (my personal account, not a catfish).

[alexander-akait]

@jsmith-sapient i will look on this in near future, anyway we glad any help

[alexander-akait]

@jsmith-sapient reproducible test repo works fine, i am use /test and it is return json. What expected?

[jsmith-sapient]

@evilebottnawi please see the commit history:

[…]

using webpack-dev-server with return req.url (working)

using webpack-dev-server (return false not working) ← checkout this commit

[alexander-akait]

@jsmith-sapient thanks, it is very strange because we have tests on this case and tests passed 😕

[jsmith-sapient]

@evilebottnawi could you link me to the test case? that might help. nvmd, it was easy to find: https://github.com/webpack/webpack-dev-server/blob/master/test/Proxy.test.js#L107-L119

[jsmith-sapient]

@evilebottnawi I think you're talking about this case:

it('should pass through a proxy when a bypass function returns null', (done) => {
  req.get('/foo.js').expect(200, /Hey/, done);
});

If so, the function does not return null:

  '/foo': {
    bypass(req) {
      if (/\.html$/.test(req.path)) {
        return '/index.html';
      }
    },
  },

[alexander-akait]

@jsmith-sapient we return nothing in this test, i think null, undefined, false is same in this context 😕

[jsmith-sapient]

I don't think so. I would expect no return to mean "go ahead, proxy, do your thing". How else would that be signalled?

[alexander-akait]

@jsmith-sapient in previous versions all works fine, right?

[JakobJingleheimer]

I haven't used bypass with previous versions.

[jsmith-sapient]

I'm having trouble finding where this is in the source code. Could you point me in the right direction?

[alexander-akait]

/cc @hiroppy need fix this problem next 👍 Should be not difficult