Node.js: Log static file requests with expressjs serve-static middleware

In most cases, every web-application requires some kind of request logging. Especially package downloads will be counted for statistic purpose. By using expressjs, static content is served by the middleware module serve-static.

To count the successfull requests handled by this module, you can hook into the setHeaders callback which is invoked each time a file is ready for delivering (file exists, file is accessible).

Example#

// utility
const _path = require('path');

// expressjs
const _express = require('express');
let _webapp = _express();

// your statistic module
const _downloadStats = require('./download-counter');

// serve static package files
_webapp.use('/downloads', _express.static(_path.join(__dirname, 'downloads'), {
    // setHeaders is only called on success (stat available/file found)
    setHeaders: function(res, path, stat){
        // count request: full-path, file-stats, client-ip
        _downloadStats(path, stat, res.req.connection.remoteAddress);
    }
}));