const express = require('express'); const { Level } = require('level'); const { recoverPersonalSignature } = require('@metamask/eth-sig-util'); // const { ecrecover, fromRpcSig, pubToAddress } = require('@ethereumjs/util'); // const { Keccak } = require('sha3'); const objectHash = require('object-hash'); // const { createHash } = require('node:crypto'); require('dotenv').config(); const app = express(); const port = process.env.PORT || 3000; const dataDir = process.env.DATA_DIR || 'data'; const db = new Level(`${dataDir}/forum`, { valueEncoding: 'json' }); // const keccak = Keccak(256); app.use(express.json()); app.post('/write', async (req, res) => { const { body: { author, content, signature } } = req; // Check author signature try { const account = recoverPersonalSignature({ data: content, signature }); if (account !== author) { console.log('error: author does not match signature'); res.status(403).end(); return; } } catch (e) { console.log('error: failed to recover signature:', e.message); res.status(400).end(); return; } // Compute content hash const data = { author, content, signature }; const hash = objectHash(data); console.log('write', hash); // Store content db.put(hash, data); // Return hash res.send(hash); }); app.get('/read/:hash', async (req, res) => { // Fetch content const { hash } = req.params; let data; try { data = await db.get(req.params.hash); } catch (e) { console.log('read error:', e.message, hash); res.status(e.status).end(); return; } console.log('read', hash); // Return content res.json(data); }); app.get('*', (req, res) => { console.log(`req.path: ${req.path}`); res.send('Hello World!'); }); app.listen(port, () => { console.log(`Listening on port ${port}`); });