91 lines
2.1 KiB
JavaScript
91 lines
2.1 KiB
JavaScript
const express = require('express');
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const { Level } = require('level');
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const { recoverPersonalSignature } = require('@metamask/eth-sig-util');
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const objectHash = require('object-hash');
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require('dotenv').config();
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const app = express();
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const port = process.env.PORT || 3000;
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const dataDir = process.env.DATA_DIR || 'data';
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const db = new Level(`${dataDir}/forum`, { valueEncoding: 'json' });
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const verifySignature = ({ author, content, signature }) => {
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try {
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const account = recoverPersonalSignature({ data: content, signature });
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if (account !== author) {
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console.log('error: author does not match signature');
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return false;
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}
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} catch (e) {
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console.log('error: failed to recover signature:', e.message);
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return false;
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}
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return true;
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};
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app.use(express.json());
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app.post('/write', async (req, res) => {
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const { body: { author, content, signature } } = req;
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// Check author signature
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if (!verifySignature({ author, content, signature })) {
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res.status(403).end();
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return;
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}
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// Compute content hash
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const data = { author, content, signature };
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const hash = objectHash(data);
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console.log('write', hash);
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// Store content
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db.put(hash, data);
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// Return hash
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res.send(hash);
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});
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app.get('/read/:hash', async (req, res) => {
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const { hash } = req.params;
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console.log('read', hash);
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// Fetch content
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let data;
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try {
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data = await db.get(req.params.hash);
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} catch (e) {
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console.log('read error:', e.message, hash);
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res.status(e.status).end();
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return;
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}
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// Verify hash
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const derivedHash = objectHash(data);
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if (derivedHash !== hash) {
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console.log('error: hash mismatch');
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res.status(500).end();
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return;
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}
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// Verify signature
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if (!verifySignature(data)) {
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console.log('error: signature verificaition failed');
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res.status(500).end();
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return;
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}
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// Return content
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res.json(data);
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});
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app.get('*', (req, res) => {
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console.log(`req.path: ${req.path}`);
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res.send('Hello World!');
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});
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app.listen(port, () => {
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console.log(`Listening on port ${port}`);
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});
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