offline-octopus/index.js

const fs = require("fs");
const http = require("http");
const https = require("https");
const path = require("path");
const {execSync}  = require('child_process');
const express = require("express");           // could be good to replace with code, no dep

// Get port or default to 8082
const port = process.env.PORT || 8082;

// Setup and configure Express http server.
const app = express();
app.use(express.static(path.resolve(__dirname, ".", "examples")));

const instructions = `
/home/deck/.ssh/
	trusted context, i.e on closed WiFi and over https, still. could check as bearer
/home/deck/.ssh/config
	could limit to known IP range or class e.g cat .ssh/config | grep 192.168.4. -C 3
	could also re-add new entries rather than extend the format
/home/deck/.ssh/authorized_keys
/home/deck/.ssh/known_hosts
/home/deck/.ssh/id_rsa_steamdeck
/home/deck/.ssh/id_rsa_steamdeck.pub

/home/deck/server.locatedb
		seems to be plain text with metadata
/home/deck/desktop.plocate.db
		seems to be a specific format, binary or maybe compressed
	both should be queriable via http with json output

ssh remarkable2 to get drawing preview
	conversion should be done, if necessary, on device
	for typed text
		cat 43*.rm | sed "s/[^a-zA-z0-9 ]//g" | sed "s/[OT,EC]//g"

util functions
	modify WiFi parameters, including AP if available
	shutdown/reboot
`
app.get('/pwa', (req, res) => {
	// for offline use on mobile or VR headset
		// should try to sync back when devices connect back
			// same when itself connects back to (Internet) own server e.g benetou.fr
			// can be cascading or federatede or properly P2P
	// responsive programming also, not "just" design
	res.redirect('pwa/index.html')
})
const utilsCmd = {
	'shutdown' : { cmd: 'shutdown -h now' },
	'listprototypes': { cmd: 'ls', context: {cwd: '/home/deck/Prototypes'},
		// more reliably path.join(__dirname,'')
		format: res => res.toString().split('\n')
	},
}
app.get('/exec', (req, res) => {
	if (!req.query.cmdName){
		res.json(utilsCmd)
	} else {

		let resultFromExecution = execSync(utilsCmd[req.query.cmdName].cmd, utilsCmd[req.query.cmdName].context) 
		let formatter = utilsCmd[req.query.cmdName].format
		if (formatter) resultFromExecution = formatter(resultFromExecution)
		res.json( resultFromExecution )
	}
})
// app.get('/interface/unregister', (req, res) => {
// app.get('/interface/register', (req, res) => {
// could be use for e.g reMarkable2, Quest2, etc with specifically accepted or prefered formats
app.get('/services/unregister', (req, res) => {
	res.json( {msg: 'not yet implemented'})
})
app.get('/services/register', (req, res) => {
	res.json( {msg: 'not yet implemented'})
	// example {name:'hmdlink', desc:'share URL between local devices', protocol:'http', port:8082, path: '/hmdlink', url:'http://192.168.4.3:8082/hmdlink'},
})
app.get('/updates', (req, res) => {
	// could rely on a git reachable by all peers
		// this might be feasible from this very https server as read-only
	res.json( {msg: 'not yet implemented'})
})
app.get('/recentfiles', (req, res) => {
	// e.g lsof | grep home | grep vim | grep -v firefox
	// or history | grep vi
	// should be available after (ideally local) conversion if needed, e.g rm -> .svg on reMarkable
	res.json( {msg: 'not yet implemented'})
})
app.get('/services', (req, res) => {
	// could be probbed first to check for availability
	// should be updated also via register/unregister
	res.json( [
		{name:'kiwix', desc:'offline Wikipedia, Stackoverflow, etc', protocol:'http', port:8080, url:'http://192.168.4.3:8080'},
		{name:'hmdlink', desc:'share URL between local devices', protocol:'http', port:8082, path: '/hmdlink', url:'http://192.168.4.3:8082/hmdlink'},

	] )
})

let dynURL = 'https://192.168.4.1/offline.html'
app.get('/hmdlink/set', (req, res) => { // could be a PUT instead
	// e.g http://192.168.4.3:8082/hmdlink/set?url=http://192.168.4.3:8082/114df5f8-3921-42f0-81e7-48731b563571.thumbnails/f07120ba-0ca1-429d-869f-c704a52b7aa3.png
	dynURL = req.query.url 
	res.redirect( dynURL )
})
app.get('/webxr', (req, res) => {
	res.redirect( '/local-metaverse-tooling/local-aframe-test.html' )
})
app.get('/hmdlink', (req, res) => {
	res.redirect( dynURL )
})
app.get('/json', (req, res) => {
	res.json( instructions.split('\n') )
})
app.get('/available', (req, res) => {
	res.json( true )
})
app.get('/foundpeers', (req, res) => {
	res.json( foundPeers )
})
let foundPeers = []
app.get('/scan', (req, res) => {
	for (let i=1;i<25;i++){ // async so blasting, gives very quick result for positives
		let url='https://192.168.4.'+i+':8082/available'
		let opt={rejectUnauthorized: false}
		https.get(url, opt, res => {
		  let data = '';
		  res.on('data', chunk => {
		    data += chunk;
		  });
		  res.on('end', () => {
		    data = JSON.parse(data);
		    foundPeers.push(i)
			  // could also register there and then
		  })
		}).on('error', err => {
		  //console.log(err.message); usually ECONNREFUSED or EHOSTUNREACH
		}).end()
	}
	res.json( {msg: 'started'} ) // could redirect('/foundpeers') too
})
app.get('/', (req, res) => {
	res.send( instructions )
})
app.get('/localprototypes', (req, res) => {
	// res.json( spawn('find Prototypes/ -iwholename */.git/config | xargs grep git.benetou.fr') )
	// should use execSync now
})
app.get('/editor/recover', (req, res) => {
	// could move the previous file with time stamp
	fs.copyFileSync(minfileSaveFullPath, fileSaveFullPath )
	res.json( {msg: 'copied'} ) 
})
/*
 * example of finding past local solution, here shiki for syntax highlighting
 *
(deck@steamdeck serverhome)$ find . -iname shiki
./fabien/web/future_of_text_demo/content/shiki
(deck@steamdeck serverhome)$ ls ./fabien/web/future_of_text_demo/content/shiki/dist/
onig.wasm

see syntax-highlighting branch in SpaSca git repository
	in /home/deck/serverhome/fabien/web/future_of_text_demo/engine/
*/
let filename = 'editor.html'
let fileSaveFullPath = path.join(__dirname,'examples', filename)
let minfilename = 'editor.html.minimal'
let minfileSaveFullPath = path.join(__dirname,'examples', minfilename)
app.get('/editor/read', (req, res) => {
	content = fs.readFileSync(fileSaveFullPath ).toString()
	res.json( {msg: content} ) 
})
app.get('/editor/save', (req, res) => {
	let content = req.query.content // does not escape, loses newlines
	if (!content){
		res.json( {msg: 'missing content'} )
	} else {
		console.log('writting', content)
		fs.writeFileSync(fileSaveFullPath, content)
		res.json( {msg: 'written to '+fileSaveFullPath} )
	}
})

const privateKey = fs.readFileSync("naf-key.pem", "utf8");
const certificate = fs.readFileSync("naf.pem", "utf8");
const credentials = { key: privateKey, cert: certificate };

const webServer = https.createServer(credentials, app);
// Start Express http server
// const webServer = http.createServer(app);
// Listen on port
webServer.listen(port, () => {
    console.log("listening on http://localhost:" + port);
});

// returns connections string for e.g sshfs
function loadSshConfig(){
	// here assume user deck
	let txt = f.readFileSync('/home/deck/.ssh/config').toString()
	return txt.split('Host ')
		.filter( m => m.match('192.168.4.') )
		.map( c => {
			p = c.replaceAll('    ','')
				.split('\n')
				.filter(i=>i.match(/^[a-zA-Z]/));
			return p.filter(pm=>pm.match('User '))[0].replace('User ','')+
				p.filter(pm=>pm.match('HostName'))[0].replace('HostName ','@')
		})
}
/*
 e.g AFTER mounting
	 f.readdirSync('./sshfsmounts/').map( d=>f.readdirSync('./sshfsmounts/'+d) )
 location : /home/deck/Prototypes/offline-octopus/sshfsmounts
  sshfs remarkable2:/home/root/xochitl-data/ remarkable2/
  works if available
  sshfs fabien@192.168.4.1:/home/fabien/ rpi0/
  still prompts for password, need manual login
  ls rpi0/
  ls remarkable2/
  */