'ERR_HTTP_HEADERS_SENT' terminate the script

[Sonsbecker]

Hello,
I use the script (as "root") with Node.js (v12) to establish a HyperBackup connection to OneDrive on a Synology server (DS214 + DSM6.2.3-25426 Update 3). I proceeded exactly according to "README". It works.

But after a while the following error messages appear and the script is terminated completely. Can no longer connect to OneDrive. Only when I restart the script.

  proxy:error [29502539/7982] Sending error response: 500 read ECONNRESET +1h                                              <<-- always other times
  proxy:error [29502539/7982] Sending error response: 500 Cannot call write after a stream was destroyed +37ms             <<-- always other times
_http_outgoing.js:526
    throw new ERR_HTTP_HEADERS_SENT('set');
    ^

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at ServerResponse.setHeader (_http_outgoing.js:526:11)
    at sendResponse (/usr/basic-to-passport-auth-http-proxy-master/lib/server.js:48:17)
    at ProxyServer.<anonymous> (/usr/basic-to-passport-auth-http-proxy-master/lib/server.js:264:5)
    at ProxyServer.emit (/usr/basic-to-passport-auth-http-proxy-master/node_modules/eventemitter3/index.js:210:27)
    at ClientRequest.proxyError (/usr/basic-to-passport-auth-http-proxy-master/node_modules/http-proxy/lib/http-proxy/passes/web-incoming.js:163:18)
    at ClientRequest.emit (events.js:310:20)
    at TLSSocket.socketErrorListener (_http_client.js:426:9)
    at TLSSocket.emit (events.js:310:20)
    at errorOrDestroy (internal/streams/destroy.js:108:12)
    at onwriteError (_stream_writable.js:418:5) {
  code: 'ERR_HTTP_HEADERS_SENT'
}

What's wrong?
Or to put it better: What can I do to ensure that the connection is automatically re-established?

many greetings

Benjamin

[skleeschulte]

If I understand correctly, you run the proxy server directly with Node.js, not with Docker? Then you could modify the file lib/server.js to help pin down the error. At the end of the file, you find the following code:

/**
 * Handle proxy errors
 */
proxy.on('error', (err, req, res) => {
    sendResponse(null, req, res, 500, err.message || '' + err);
});

Change it to:

/**
 * Handle proxy errors
 */
proxy.on('error', (err, req, res) => {
    const errorMessage = err.message || '' + err;
    log.e(`[${req.__requestId}] Proxy error: ${errorMessage}`);
    sendResponse(null, req, res, 500, errorMessage);
});

Then restart the server, wait for the error to reappear and post the log output here. Thank you!

[Sonsbecker]

I made the change.
However, I don't see any change in the output.
Here is the full output after starting the script.

`
added 17 packages, and audited 18 packages in 6s

2 high severity vulnerabilities

To address all issues (including breaking changes), run:
npm audit fix --force

Run npm audit for details.
proxy:info Proxy server listening: { address: '::', family: 'IPv6', port: 3000 } +0ms
proxy:error socket hang up +0ms
proxy:error [8820/9154] Sending error response: 500 socket hang up +2ms
proxy:error read ECONNRESET +31m
proxy:error [1859697/1246] Sending error response: 500 read ECONNRESET +111ms
proxy:error write ETIMEDOUT +3h
proxy:error [12533928/9443] Sending error response: 500 write ETIMEDOUT +4ms
_http_outgoing.js:526
throw new ERR_HTTP_HEADERS_SENT('set');
^

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
at ServerResponse.setHeader (_http_outgoing.js:526:11)
at sendResponse (/usr/basic-to-passport-auth-http-proxy-master/lib/server.js:48:17)
at ProxyServer. (/usr/basic-to-passport-auth-http-proxy-master/lib/server.js:271:5)
at ProxyServer.emit (/usr/basic-to-passport-auth-http-proxy-master/node_modules/eventemitter3/index.js:210:27)
at ClientRequest.proxyError (/usr/basic-to-passport-auth-http-proxy-master/node_modules/http-proxy/lib/http-proxy/passes/web-incoming.js:163:18)
at ClientRequest.emit (events.js:310:20)
at TLSSocket.socketErrorListener (_http_client.js:426:9)
at TLSSocket.emit (events.js:310:20)
at errorOrDestroy (internal/streams/destroy.js:108:12)
at onwriteError (_stream_writable.js:424:5) {
code: 'ERR_HTTP_HEADERS_SENT'
}
`

Or is there a log file somewhere where the errors are recorded?

[skleeschulte]

I suggest to run the script with forever or to use the provided Docker image, which uses forever internally. The forever command in the Docker image is forever --minUptime 1000 --spinSleepTime 1000 lib/server.js. This is a hacky workaround which restarts the script whenever it crashes, but might be a solution depending on the root cause for the ECONNRESET error.