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
// express does not seem architecture dependant thus copying node_modules sufficed for now
// (worked at least on RPi, Deck, Quest and x64 machines)

// Get port or default to 8082
const port = process.env.PORT || 8082;
const protocol = 'https'
const subclass = '192.168.4.'

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

process.title = 'offtopus' // offline-octopus seems too long

const filename = 'editor.html'
const fileSaveFullPath = path.join(__dirname,'examples', filename)
const minfilename = 'editor.html.minimal'
const minfileSaveFullPath = path.join(__dirname,'examples', minfilename)

const sshconfigpath = path.resolve(process.env.HOME,'.ssh','config')
const propath = path.resolve(process.env.HOME,'Prototypes')

// does not apply in a P2P fashion, must rely on local configuration here config.json
let localServices = [ ]
const configFilePath = path.resolve(__dirname, "config.json")
if (fs.existsSync( configFilePath ) ){
	const configurationFromFile = JSON.parse( fs.readFileSync( configFilePath ).toString() )
	localServices = configurationFromFile
}
console.log(localServices)

const utilsCmd = { // security risk but for now not accepting user input so safer
	//'update' : { desc: 'note that will lose the state, e.g foundpeers', cmd: 'killall '+process.title+' && ' },
	// should first download the new version and proceed only if new
		// e.g git clone deck@localhost:~/Prototypes/offline-octopus/
		// should see /sshconfig
	// ideally all handles within node
	'shutdown' : { cmd: 'shutdown -h now' }, // not available everywhere, e.g unrooted Quest
	'listprototypes': { cmd: 'ls', context: {cwd: propath},
		format: res => res.toString().split('\n')
	},
}

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/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
		not feasible right now without toltec to get opkg to get node
	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
`

const auth_instructions = `generate md5 from pub offline-octopus then provide as bearer query param`

app.get('/', (req, res) => {
	res.send( instructions )
})

app.get('/authtest', (req, res) => {
	if (req.query?.bearer != md5fromPub){ res.send( auth_instructions); return; }
	// relying on this line for each specific route
		// this is NOT authentification proper, even less secure
		// this is done ONLY to avoid mistakes on a secure LAN
	res.json( {msg: "success"} )
})
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')
	// see also /editor
})

let resultFromLastGlobalCmd = {}

// should check on e.g publicKey or md5fromPub 
app.get('/allpeers/exec', (req, res) => {
	if (req.query?.bearer != md5fromPub){ res.send( auth_instructions); return; }
	if (!req.query.cmdName){
		res.json(utilsCmd)
	} else {
		foundPeers.map( i => {
			let url=protocol+'://'+subclass+i+':'+port
				+'/exec?cmdName='+req.query.cmdName
				+'&bearer='+req.query.bearer
			let opt={rejectUnauthorized: false}
			https.get(url, opt, res => {
			  let data = '';
			  res.on('data', chunk => {
			    data += chunk;
			  });
			  res.on('end', () => {
				  console.log('data', url, data)
			    data = JSON.parse(data);
			    resultFromLastGlobalCmd[url] = data
			  })
			}).on('error', err => {
			  console.log(err.message);
			}).end()
		})
		res.json( {msg: 'started'} ) // could redirect('/all/result') too after a timeout
	}
})
app.get('/allpeers/result', (req, res) => {
	res.json( resultFromLastGlobalCmd )
})

app.get('/exec', (req, res) => {
	if (req.query?.bearer != md5fromPub){ res.send( auth_instructions); return; }
	if (!req.query.cmdName){
		res.json(utilsCmd)
	} else {
		res.json( execConfiguredCommand(req.query.cmdName) )
	}
})

function execConfiguredCommand(cmdName){
	let resultFromExecution = execSync(utilsCmd[cmdName].cmd, utilsCmd[cmdName].context) 
	let formatter = utilsCmd[cmdName].format
	if (formatter) resultFromExecution = formatter(resultFromExecution)
	return 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
		// surely feasible via ssh
	// could killall offtopus first then pull then restart detached
	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( localServices )
})

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('/hmdlink', (req, res) => {
	res.redirect( dynURL )
})

app.get('/webxr', (req, res) => {
	res.redirect( '/local-metaverse-tooling/local-aframe-test.html' )
})

// user for /scan to populate foundPeers
app.get('/available', (req, res) => {
	res.json( true )
})

app.get('/foundpeers', (req, res) => {
	res.json( foundPeers )
})

let foundPeers = []
app.get('/scan', (req, res) => {
	scanpeers()
	res.json( {msg: 'started'} ) // could redirect('/foundpeers') too after a timeout
})

function scanpeers(){
	foundPeers = []
	for (let i=1;i<25;i++){ // async so blasting, gives very quick result for positives
		let url=protocol+'://'+subclass+i+':'+port+'/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()
	}
}

app.get('/sshconfig', (req, res) => {
	res.json( getSshConfig() )
	// should filter on foundPeers to avoid offline peers
})

// returns connections string for e.g sshfs
function getSshConfig(){
	// here assume user deck
	let txt = fs.readFileSync(sshconfigpath).toString()
	return txt.split('Host ')
		.filter( m => m.match(subclass) )
		.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/

  must be done after passwordless login, i.e after ssh-copy-id
  	made a dedicated key : /home/deck/.ssh/id_rsa_offlineoctopus
	easier to revoke if need be
  */

const publicKeyPath = path.resolve(process.env.HOME,'.ssh','id_rsa_offlineoctopus.pub')
const publicKey = fs.readFileSync(publicKeyPath).toString().split(' ')[1]

const md5fromPub = fs.readFileSync( path.resolve(__dirname, ".keyfrommd5")).toString().replace('\n','')

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/
*/


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 "+protocol+"://localhost:" + port);
});