@digipolis/request-log/lib/request.middleware.js

Log express and external Requests in digipolis format

const { createLogger } = require('./helpers/requestlogger');
const { validateConfig } = require('./helpers/config');
const startTimer = require('./helpers/requesttimer');

module.exports = (config) => {
  const validatedConfig = validateConfig(config);
  const logger = createLogger(validatedConfig);

  return (req, res, next) => {
    const timer = startTimer();
    let responsebody = '';

    if (validatedConfig.logResponsePayload) {
      res.write = new Proxy(res.write, {
        apply(target, thisArg, args) {
          responsebody += args[0].toString();
          target.apply(thisArg, args);
        },
      });
    }

    res.end = new Proxy(res.end, {
      apply(target, thisArg, args) {
        let correlationId;
        if (validatedConfig.correlationIdLocation) {
          correlationId = validatedConfig.correlationIdLocation.split('.').reduce((acc, key) => {
            if (!acc || !acc[key]) {
              if (validatedConfig.correlationIdfallback) return validatedConfig.correlationIdfallback;
              return undefined;
            }
            return acc[key];
          }, req);
        } else {
          correlationId = req.headers['Dgp-Correlation'] || req.headers['dgp-correlation'] || validatedConfig.correlationIdfallback;
        }
        if (validatedConfig.logResponsePayload && args[0]) responsebody += args[0].toString();
        const path = validatedConfig.logRequestSearchParams ? req.originalUrl : req.originalUrl.split(req._parsedUrl.search)[0];
        logger.reqlog({
          correlationId,
          request: {
            headers: req.headers,
            host: req.get('host'),
            path,
            method: req.method,
            payload: req.body,
          },
          response: {
            headers:  { ...res.getHeaders() },
            status: res.statusCode,
            duration: timer.getDuration(),
            payload: responsebody,
          },
          protocol: req.protocol,
        });
        target.apply(thisArg, args);
      },
    });

    return next();
  };
};