# Browser Fingerprint

[![test](https://github.com/actionhero/browser_fingerprint/actions/workflows/test.yml/badge.svg)](https://github.com/actionhero/browser_fingerprint/actions/workflows/test.yml)

[![NPM](https://nodei.co/npm/browser_fingerprint.png)](https://nodei.co/npm/browser_fingerprint/)

**Note: This package requires node v8, as it makes uses of native classes.**

This module attempts to uniquely identify browsers by examining their header and connection information. This information can be used as a "poor-man's" session identifier in your node projects. This module can optionally set a cookie to 'lock' in a consistent fingerprint.

Resuming sessions require that either the cookie be returned to the server, or a x-header `x-__browserFingerprint` in the default case, be sent on subsequent requests

```javascript
const http = require("http");
const port = 8080;

const { BrowserFingerprint } = require("browser_fingerprint");

// these are the default options
const options = {
  cookieKey: "__browser_fingerprint",
  toSetCookie: true,
  onlyStaticElements: true,
  settings: {
    path: "/",
    expires: 3600000,
    httpOnly: null,
  },
};

const fingerPrinter = new BrowserFingerprint(options);

http
  .createServer((req, res) => {
    let { fingerprint, elementsHash, headersHash } = fingerPrinter.fingerprint(
      req
    );
    headersHash["Content-Type"] = "text/plain"; // append any other headers you want
    res.writeHead(200, headersHash);

    let resp = `Your Browser Fingerprint: ${fingerprint} \r\n\r\n`;
    for (let i in elementsHash) {
      resp += `Element ${i}: ${elementsHash[i]}\r\n`;
    }

    res.end(resp);
    console.log(
      "request from " +
        req.connection.remoteAddress +
        ", fingerprint -> " +
        fingerprint
    );
  })
  .listen(port);

console.log(`server running at http://127.0.0.1:${port}`);
```