Introduction

This is a JavaScript utility to trace the original URL of a shortened URL (or any URL with redirection).

Usage

Via Command-Line

node trace.js http://example.com/shortened-URL-you-want-to-resolve

You can invoke trace.js via command-line with one URL you want to look up, for example:

> node trace.js http://catchen.biz/home.en.html
resolving: http://catchen.biz/
resolving: https://catchen.me/
resolved: https://catchen.me/

As an NPM Package

await require('traceurl').promisified.trace('http://example.com/shortened-URL-you-want-to-resolve');

You can install traceurl via NPM:

npm install traceurl

Then you can use it as in your project, for example:

const traceurl = require('traceurl');
const resolvedURL = await traceurl.promisified.trace('http://catchen.biz/home.en.html');
console.log(resolvedURL);

If multiple redirections are involved, trace function will give you the final non-redirecting URL while traceHops function will give you a list of all involving URLs:

const traceurl = require('traceurl');
const hops = await traceurl.promisified.traceHops('http://catchen.biz/home.en.html');
console.log(hops);

Legacy API

The legacy API uses Async module from jsHelpers, which was a Promise-like utility before Promise. It uses the addCallback method in a way that's similar to Promise's then method. We keep to legacy API to prevent breaking change.

const traceurl = require('traceurl');
traceurl.trace('http://catchen.biz/home.en.html').addCallback(function(resolvedURL) {
  console.log(resolvedURL);
});
traceurl.traceHops('http://catchen.biz/home.en.html').addCallback(function(hops) {
  console.log(hops);
});