// Credit: https://github.com/jinty/prerender-cloudfront // Credit: https://aws.amazon.com/blogs/networking-and-content-delivery/dynamically-route-viewer-requests-to-any-origin-using-lambdaedge/ exports.handler = (event, context, callback) => { const request = event.Records[0].cf.request; const headers = request.headers; const user_agent = headers['user-agent']; if (user_agent) { var prerender = /googlebot|bingbot|yandex|baiduspider|Facebot|facebookexternalhit|twitterbot|rogerbot|linkedinbot|embedly|quora link preview|showyoubot|outbrain|pinterest|slackbot|vkShare|W3C_Validator/i.test(user_agent[0].value); prerender = prerender || /_escaped_fragment_/.test(request.querystring); prerender = prerender && ! /\.(css|xml|less|png|jpg|jpeg|gif|pdf|doc|txt|ico|rss|zip|mp3|rar|exe|wmv|doc|avi|ppt|mpg|mpeg|tif|wav|mov|psd|ai|xls|mp4|m4a|swf|dat|dmg|iso|flv|m4v|torrent|ttf|woff|svg|eot)$/i.test(request.uri); if (prerender) { // if a query string provided remove the query string and replace the ? with a + (translated to space with S3) if (request.querystring) { request.uri += `+${request.querystring}`; request.querystring = '' } // Return the prerendering bucket to S3 const s3DomainName = process.env.s3DomainName; request.origin = { s3: { domainName: s3DomainName, region: '', authMethod: 'none', path: '', customHeaders: {} } }; request.headers['host'] = [{ key: 'host', value: s3DomainName }]; console.log(user_agent[0].value, "requesting", request.uri); } } callback(null, request); };