1 files changed, 71 insertions, 0 deletions
diff --git a/webapp/main.js b/webapp/main.js
new file mode 100644
index 0000000..fd445a4
--- /dev/null
+++ b/webapp/main.js
@@ -0,0 +1,71 @@
+const express = require('express')
+const app = express()
+const jwt = require('jsonwebtoken')
+const Web3 = require('web3')
+const port = 4000
+
+const web3 = new Web3('https://cloudflare-eth.com/')
+const jwtSecret = 'some very secret value'
+
+app.use(express.static('public'))
+
+app.get('/nonce', (req, res) => {
+  const nonce = new Date().getTime()
+  const address = req.query.address
+
+  const tempToken = jwt.sign({ nonce, address }, jwtSecret, { expiresIn: '60s' })
+  const message = getSignMessage(address, nonce)
+
+  res.json({ tempToken, message })
+})
+
+app.post('/verify', async (req, res) => {
+  const authHeader = req.headers['authorization']
+  const tempToken = authHeader && authHeader.split(" ")[1]
+
+  if (tempToken === null) return res.sendStatus(403)
+
+  const userData = await jwt.verify(tempToken, jwtSecret)
+  const nonce = userData.nonce
+  const address = userData.address
+  const message = getSignMessage(address, nonce)
+  const signature = req.query.signature
+
+  const verifiedAddress = await web3.eth.accounts.recover(message, signature)
+
+  if (verifiedAddress.toLowerCase() == address.toLowerCase()) {
+    const token = jwt.sign({ verifiedAddress }, jwtSecret, { expiresIn: '1d' })
+    res.json({ token })
+  } else {
+    res.sendStatus(403)
+  }
+})
+
+app.get('/secret', authenticateToken, async (req, res) => {
+  res.send(`Welcome address ${req.authData.verifiedAddress}`)
+})
+
+function authenticateToken(req, res, next) {
+  const authHeader = req.headers['authorization']
+  const token = authHeader && authHeader.split(' ')[1]
+
+  if (token == null) return res.sendStatus(401)
+
+  jwt.verify(token, jwtSecret, (err, authData) => {
+    console.log(err)
+
+    if (err) return res.sendStatus(403)
+
+    req.authData = authData
+
+    next()
+  })
+}
+
+const getSignMessage = (address, nonce) => {
+  return `Please sign this message for address ${address}:\n\n${nonce}`
+}
+
+app.listen(port, () => {
+  console.log(`Example app listening on port ${port}`)
+})
+\ No newline at end of file