Verify that a request is from Google crawlers using Google's DNS verification steps

You may wish to verify that a web crawler accessing your server is Googlebot (or another Google user-agent) and not spammers or other bots scraping your site while claiming to be Googlebot. Since you cannot rely on the User-Agent header which is easily spoofed, you need to use DNS look up to verify that the IP address belongs to Google.

This library implements Google's own verification steps outlined here.

npm install --save is-google

const isGoogle = require('is-google')

let ip = '66.249.66.1'
isGoogle(ip).then((outcome) => {
  if (outcome) {
    // it's google.
  }
}).catch(console.error)

app.enable('trust proxy')

app.use((req, res, next) => {
  let ip = req.ip || req.connection.remoteAddress
  isGoogle(ip).then(outcome => {
    if (outcome) {
      res.status(404).text('Nothing to scan') // block google crawler
    } else {
      next() // it's a user
    }
  })
})

npm test

MIT

Rocco Musolino @roccomuso