origin.js

// Configure this
const swAdnToken            = "XXXXXXX"; // Set the ADN token provided by Botify
const swAllowedUrls         = [];   // Set something like https://mysubdomain.mydomain.com/mypages (in lower case) to restrict SW to urls starting with these values
const swRewriteOrigin       = "";   // Set something like https://www.mydomain.com

const swDomain              = "XXXXXXXX.sw.adn.cloud"; // Set the SpeedWorkers domain name provided by Botify (no "https://" or trailing "/" here, only the domain)
const swPort                = 443;
const swProtocol            = "https";
const swSslProtocols        = ["TLSv1", "TLSv1.1", "TLSv1.2"];
const swReadTimeoutSec      = 15;
const swKeepaliveTimeoutSec = 60;
const swCustomHeaders       = {}; // Use this format: "user-agent": [ { "value": "ExampleCustomUserAgent/1.X.0"}], ... // https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/lambda-event-structure.html#request-event-fields-request-headers


// Don't touch this
const swAgent    = "CloudFrontInterceptor/1.1";
const swIgnored  = ["/css/", "/fonts/", "/images/", "/js/", "/scss/", ".bmp", ".css", ".csv", ".doc", ".docx", ".eot", ".gif", ".ico", ".ief", ".jpe", ".jpeg", ".jpg", ".js", ".json", ".less", ".map", ".m1v", ".mov", ".mp2", ".mp3", ".mp4", ".mpa", ".mpe", ".mpeg", ".mpg", ".otf", ".ott", ".ogv", ".pbm", ".pdf", ".pgm", ".png", ".ppm", ".pnm", ".ppt", ".pps", ".ps", ".qt", ".ras", ".rdf", ".rgb", ".rss", ".svg", ".swf", ".tiff", ".tif", ".tsv", ".ttf", ".txt", ".vcf", ".wav", ".webm", ".woff", ".woff2", ".xbm", ".xlm", ".xls", ".xml", ".xpdl", ".xpm", ".xwd"]; // in lower case

// Set to true if you want debug logs
const debug      = true

exports.handler = (event, context, callback) => {

    const request = event.Records[0].cf.request;

    // Ignore web sockets
    // Ignore web sockets
    if (request.headers["Upgrade"] === "websocket") {
        log("websocket, ignoring request")
        callback(null, request);
        return;
    }

    // Only filter GETs and HEADs
    const requestMethod = request.method
    if (requestMethod !== "GET" && requestMethod !== "HEAD") {
        log("not a GET/HEAD method, ignoring");
        callback(null, request);
        return;
    }

    // We need a way to know if the request comes from a bot or a user
    // If the request doesn't come from a bot, let it reach the fallback origin without SW
    if (
        request.headers["x-sw-request-type"] === undefined
        || (request.headers["x-sw-request-type"] !== undefined && !request.headers["x-sw-request-type"][0].value.startsWith("bot"))
    )
    {
        delete request.headers["x-sw-request-type"];
        log("not a bot (or missing x-sw-request-type header), ignoring");
        callback(null, request);
        return;
    }
    delete request.headers["x-sw-request-type"];

    // We need the host from the Viewer Request Lambda, or at least a rewrite origin value!
    if (request.headers["x-sw-host"] === undefined && (swRewriteOrigin === undefined || swRewriteOrigin === ""))
    {
        log("missing x-sw-host, no viewer request lambda?");
        callback(null, request);
        return;
    }

    // Retrieve original host set by the viewer request lambda
    let originalHost = "";
    if (request.headers["x-sw-host"] !== undefined) {
        originalHost = request.headers["x-sw-host"][0].value;
        delete request.headers["x-sw-host"];
    }

    // Rebuild the complete uri
    let url = "https://" + originalHost;
    if (swRewriteOrigin !== undefined && swRewriteOrigin !== "") {
        url = swRewriteOrigin;
    }
    url += request.uri;
    if (request.querystring !== "")
    {
        url += "?" + request.querystring;
    }

    // Ignore requests which url doesn't start with one of the url SW is enabled
    if (!isUrlAllowed(url))
    {
        log("url (" + url + ") not allowed, ignoring");
        callback(null, request);
        return;
    }

    // Ignore resources that are not handled by SW
    if (ignorePath(url))
    {
        log("path " + url + " ignored");
        callback(null, request);
        return;
    }

    // The request comes from a bot, send it to SW
    log("calling SW to get " + url);

    // Restore user-agent header (to replace Amazon CloudFront user-agent...)
    // If you don't use the viewer request, please make sure you whitelisted the User-Agent header in the CloudFront conf
    if (request.headers["x-sw-user-agent"] !== undefined) {
        request.headers['user-agent'] = [{ key: 'User-Agent', value: request.headers["x-sw-user-agent"][0].value }];
        delete request.headers["x-sw-user-agent"];
    }
    request.headers["host"] = [{ key: "host", value: swDomain }];

    request.origin = {
        custom: {
            domainName:        swDomain,
            port:              swPort,
            protocol:          swProtocol,
            sslProtocols:      swSslProtocols,
            readTimeout:       swReadTimeoutSec,
            keepaliveTimeout:  swKeepaliveTimeoutSec,
            customHeaders:     swCustomHeaders
        }
    };

    request.origin.custom.customHeaders["x-sw-agent"]           = [{ key: "x-sw-agent",           value: swAgent }];
    request.origin.custom.customHeaders["x-sw-client-ip"]       = [{ key: "x-sw-client-ip",       value: request.clientIp }];
    request.origin.custom.customHeaders["x-sw-uri"]             = [{ key: "x-sw-uri",             value: url }];
    request.origin.custom.customHeaders["x-sw-adn-token"]       = [{ key: "x-sw-adn-token",     value: swAdnToken }];

    callback(null, request);
};

function log(msg) {
    if (debug) {
        console.log(msg)
    }
}

// Returns true if the url contains a path sw should ignore
function ignorePath(url)
{
    for (let i = 0; i < swIgnored.length; i++)
    {
        if (url.toLowerCase().includes(swIgnored[i]))
            return true;
    }

    return false;
}


// Returns true if the url belongs to (starts with) an allowed url
function isUrlAllowed(url) {

    if (swAllowedUrls.length === 0)
        return true;

    for (let i = 0; i < swAllowedUrls.length; i++)
    {
        if (url.toLowerCase().startsWith(swAllowedUrls[i]))
            return true;
    }

    return false;
}