JS Fetch sniffer v 0.1

gistfile1.txt

// This PoC code can hook into a JS app, and sniff for all REST connections happening
// storing them into local storage
// 
// How to use it
// Open crome, press F12 in the page you wanna sniff the connections
// launch
initFetchSniffer()
let response = await fetch(`https://api.github.com/users/gnuton`);
await response.json()
fetchLog()

//------- The Code -----------
const initFetchSniffer= () => {
	// Initialize localStorage and functions
	const LS_FETCH_LOG_KEY = 'fetchLog'
	localStorage.setItem(LS_FETCH_LOG_KEY, JSON.stringify([]))

	window.fetchLog = () => {
	  return JSON.parse(localStorage.getItem(LS_FETCH_LOG_KEY))
	}

	window.storeFetchLog = (data) => {
	  const logs = fetchLog();
	  logs.push(data);
	  localStorage.setItem(LS_FETCH_LOG_KEY, JSON.stringify(logs));
	}


	// Override fetch function
	window.original_fetch = fetch
	fetch = (...args) => {
	  storeFetchLog(...args);
	  return window.original_fetch(...args);
	}
}