Need help debugging

[bpracht]

Is there a way to get the final pathRewrite URL that gets sent to the target server? I'm using what I'd call a declarative syntax, preventing me from just calling console.log to get the final URL. If it helps, I'm providing the background of what I'm trying to do. I'd like to know if there's some place that I can call something like {
console.log('http-proxy-middleware res.targetUrl='+someObject.finalUrlAfterPathRewrite
}

Background: My middleware app is not forwarding properly and I'm getting errors like the ones below.

Please note, I already tried using DEBUG=express-http-proxy, but that didn't add any extra information. I wish to take the incoming request to localhost/spreadsheet-upload, add SSO type headers, pass that on to the spreadsheet-upload server, and return the results as if it went directly to the spreadsheet-upload.

ERROR Error: Uncaught (in promise): Error: Cannot match any routes. URL Segment: 'spreadsheet-upload'
./node_modules/@angular/router/fesm5/router.js/ApplyRedirects.prototype.noMatchError@https://localhost:8080/vendor.js:68322:16
./node_modules/@angular/router/fesm5/router.js/ApplyRedirects.prototype.apply/<@https://localhost:8080/vendor.js:68303:29
./node_modules/rxjs/_esm5/internal/operators/catchError.js/CatchSubscriber.prototype.error@https://localhost:8080/vendor.js:82540:31
./node_modules/rxjs/_esm5/internal/Subscriber.js/Subscriber.prototype._error@https://localhost:8080/vendor.js:77522:26
./node_modules/rxjs/_esm5/internal/Subscriber.js/Subscriber.prototype.error@https://localhost:8080/vendor.js:77496:18
./node_modules/rxjs/_esm5/internal/Subscriber.js/Subscriber.prototype._error@https://localhost:8080/vendor.js:77522:26
./node_modules/rxjs/_esm5/internal/Subscriber.js/Subscriber.prototype.error@https://localhost:8080/vendor.js:77496:18
./node_modules/rxjs/_esm5/internal/Subscriber.js/Subscr…
    resolvePromise https://localhost:8080/polyfills.js:3170
    resolvePromise https://localhost:8080/polyfills.js:3127
    scheduleResolveOrReject https://localhost:8080/polyfills.js:3231
    invokeTask https://localhost:8080/polyfills.js:2762
    onInvokeTask https://localhost:8080/vendor.js:42628
    invokeTask https://localhost:8080/polyfills.js:2761
    runTask https://localhost:8080/polyfills.js:2534
    drainMicroTaskQueue https://localhost:8080/polyfills.js:2940
vendor.js:40490:19
[WDS] Disconnected! vendor.js:101527:9

The relevant route snippet is:

    app.use(['/spreadsheet-upload', '/spreadsheet-upload/*'], ensureAuthenticated,
        function (req, res, next) {
            logger.debug('Route for spreadsheet-upload originalUrl=' + req.originalUrl + ': Forwarding to ' + config.spreadsheet_client_host);
            next();
        },
        createProxyMiddleware({
            target: config.spreadsheet_client_host,
            changeOrigin: true,
            limit: "3mb",
            memoizeHost: false,
            preserveHostHdr: true,
            https: false,
            secure: false,
            proxyErrorHandler: function (err, res, next) {
                util.inspect(err);
                next();
            },
            logLevel: 'debug',
            onProxyReq: function (proxyReq, req, rsp) {
                Object.keys(req.headers).forEach(function (key) {
                    proxyReq.setHeader(key, req.headers[key]);
                });
                var accessToken = generateToken(req.user);
                /**
                 * Set bearer token based on code from Sprint-API's lua code
                 */
                proxyReq.setHeader('Authorization', 'Bearer ' + accessToken);
            },
            onProxyRes: function onProxyRes(proxyRes, req, res) {
                Object.keys(proxyRes.headers).forEach(function (key) {
                    res.append(key, proxyRes.headers[key]);
                });
            },
            router: {
                '.*:8080': config.spreadsheet_client_host
            },
            pathRewrite: {
                '^\/spreadsheet-upload\/': '/'
            },
        })
    );

[chimurai]

Think you could use onProxyRes

  onProxyRes: (proxyRes, req, res) => {
    // log original request and proxied request info
    const exchange = `[DEBUG] ${req.method} ${req.path} -> ${proxyRes.req.protocol}//${proxyRes.req.host}${proxyRes.req.path} [${proxyRes.statusCode}]`;
    console.log(exchange);  // [DEBUG] GET / -> http://www.example.com [200]
  }),