How to hide "Proxy error: Could not proxy request ..." from the terminal

[stas-kh]

I am using http-proxy-middleware in my VueJS application as a proxy tool.

Here is my simple configuration of devServer in vue.config.js:

  devServer: {
    host: "localhost",
    port: 8081,
    proxy: {
      "^/api": {
        target: "http://localhost:11339",
        ws: true,
        changeOrigin: true,
      },
    },
  },

Recently I've introduced cancelling of some HTTP requests and it causes this kind of error in terminal when devServer is running:

Proxy error: Could not proxy request %request_url% from localhost:8081 to http://localhost:11339.
See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (ECONNRESET).

I would like to hide such errors from the terminal because I cancel requests manually and it's expected.

I've tried a couple of solutions:

1. Setting logLevel: silent to proxy config
2. Applying this hook to catch an error:

onProxyReq: (proxyReq, req, res) => {
  req.on("error", function(err) {
    console.warn("ERROR, ", err);
  });
},

None of the options could help me to hide these ECONNRESET errors.

I would appreciate if someone can help me in this question.

[chimurai]

http-proxy-middleware log statements are prefixed with [HPM].

The message you're seeing is probably coming from http-proxy.

Found this undocumented econnreset proxy event in @types/http-proxy.
https://github.com/DefinitelyTyped/DefinitelyTyped/blob/0ebb554617399eadb906c4262823bf9f3fcbfa6f/types/http-proxy/index.d.ts#L151-L159

This econnreset proxy event is not documented on:
https://github.com/http-party/node-http-proxy#listening-for-proxy-events

Can you try to patch and manually subscribe to econnreset?

http-proxy-middleware/src/http-proxy-middleware.ts

Line 34 in e204345

this.proxy.on('error', this.logError);

this.proxy.on('error', this.logError); 
this.proxy.on('econnreset', () => { // do nothing })

If this works I can expose the missing events.

[stas-kh]

@chimurai thanks for your quick response.

I've patched the library with the following line but it didn't help a lot:

proxy.on('econnreset', () => {})

I was able to extend my vue.config.js with this configuration:

onProxyReq: (proxyReq, req, res) => {
  req.on("error", function(err) {
    console.warn(`Error -`, err);
  });
}

and I see that the error gets caught:

Proxy error: Could not proxy request %request_url% from localhost:8081 to http://localhost:11339.
See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (ECONNRESET).

ERROR - Error: aborted
    at connResetException (node:internal/errors:621:14)
    at abortIncoming (node:_http_server:579:25)
    at socketOnEnd (node:_http_server:596:5)
    at Socket.emit (node:events:339:22)
    at endReadableNT (node:internal/streams/readable:1289:12)
    at processTicksAndRejections (node:internal/process/task_queues:80:21) {
  code: 'ECONNRESET'
}

Proxy error: Could not proxy request %request_url% from localhost:8081 to http://localhost:11339.
See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (ECONNRESET).

But the error messages are still displayed in the terminal.

The only one solution that helped was commenting out this line in http-proxy repository:
https://github.com/http-party/node-http-proxy/blob/9b96cd725127a024dabebec6c7ea8c807272223d/lib/http-proxy/passes/web-incoming.js#L165

@chimurai what would you suggest me to do about it?

Thanks in advance!

[chimurai]

The error message does look like this message, but not exactly the same.

http-proxy-middleware/src/http-proxy-middleware.ts

Lines 191 to 192 in e204345

	const errorMessage = '[HPM] Error occurred while proxying request %s to %s [%s] (%s)';
	const errReference = 'https://nodejs.org/api/errors.html#errors_common_system_errors'; // link to Node Common Systems Errors page

Which version of http-proxy-middleware are you using?

[stas-kh]

Here are the versions used:

http-proxy-middleware@0.19.1
http-proxy@^1.17.0

The text of the error is taken from vue-cli-service from the function onProxyError

[chimurai]

Are you able to replicate the error with a minimal setup and latest versions?

express + http-proxy-middleware

express().use(createProxyMiddleware({
  target: "http://localhost:11339",
  ws: true,
  changeOrigin: true,
}))
.listen(8081)

Without an isolated example there is little to investigate.