Automatically replying to OPTIONS requests is potentially problematic

[MarceloZabini]

Bug report

OPTIONS requests are automatically handled by webpack-dev-server since #4180 was implemented by #4185, bypassing the application's backend.

Actual Behavior

webpack-dev-server automatically replies to OPTIONS requests regardless of how the backend application would handle it.

Expected Behavior

Much like any other kind of requests, like GET and POST, OPTIONS requests should by default be forwarded to the application. Applications can reply with a failure depending on the request, and can include a variety of response headers which can be important for the application.

How Do We Reproduce?

Use webpack-dev-server 4.10.0, which contains #4185, and any application that handles OPTIONS requests in the backend to see that the backend application isn't even contacted.

Please paste the results of npx webpack-cli info here, and mention other relevant information

System:
OS: Linux 5.14 Fedora 33 (Workstation Edition) 33 (Workstation Edition)
CPU: (8) x64 Intel(R) Core(TM) i5-8250U CPU @ 1.60GHz
Memory: 7.60 GB / 15.38 GB
Binaries:
Node: 14.19.3 - /nix/store/cnma41dzr06jp8j6vigfp4lmy1dqfg3x-nodejs-14.19.3/bin/node
npm: 6.14.17 - /nix/store/cnma41dzr06jp8j6vigfp4lmy1dqfg3x-nodejs-14.19.3/bin/npm

[alexander-akait]

@MarceloZabini What about if we implement an option for this? So you can disable it when you need

[MarceloZabini]

There is perhaps a discussion of what users expect the default to be (personally I'd expect every request to be proxied), but having the option available and documented would certainly be good enough - at least for me.

[alan-agius4]

This has also been reported in angular/angular-cli#23857

I wonder if it's just a matter of registering the options-middleware as the last middleware, which will act as a fallback if none of the other middlewares handles the OPTIONS.

[alan-agius4]

Are you able to test if by updating node_modules/webpack-dev-server/lib/Server.js to https://gist.github.com/alan-agius4/156a7c36c2927986ef4e1dc6ffcdc97a the issue still persists?

Edit: Based on the reproduction in angular/angular-cli#23859 it does seem like it's a matter of registration order.

[sek1973]

We also have problems with OPTIONS requests handled this way.
I reported it to Angular team, as webpack-dev-server@4.10.0 is internally used by @angular-devkit/build-angular@14.2.1. Please find details here https://github.com/angular/angular-cli/issues/23857.
I also described a workaround for OPTIONS requests to be handled properly.

[alan-agius4]

Another user confirmed my suspicions that it’s a matter of ordering.

See: angular/angular-cli#23857 (comment)

[snitin315]

Feel free to send a PR.

[alexander-akait]

@alan-agius4 hm, do you have a valid order (confirmed that we don't have the issue again)?

[alan-agius4]

@alexander-akait, yeah it need to be registered as the last middleware as per the gist (https://gist.github.com/alan-agius4/156a7c36c2927986ef4e1dc6ffcdc97a) that the above users used to verify this.

[alexander-akait]

Please update to https://github.com/webpack/webpack-dev-server/releases/tag/v4.11.0