Clout Kit Web Services using server to server token

index.js

(function() {

    /**
     * This is an example fetching /users/current from cloud kit with a server to server token without utilising aplpe's cloudkit.js
     * https://developer.apple.com/library/ios/samplecode/CloudAtlas/Listings/Node_node_client_s2s_index_js.html#//apple_ref/doc/uid/TP40014599-Node_node_client_s2s_index_js-DontLinkElementID_22
     */

    const https = require('https');
    var fs = require('fs');
    var crypto = require('crypto');

    // using config from cloud kit catalog example https://developer.apple.com/library/ios/samplecode/CloudAtlas/Listings/Node_node_client_s2s_config_js.html#//apple_ref/doc/uid/TP40014599-Node_node_client_s2s_config_js-DontLinkElementID_21
    var containerConfig = require('./config');
    var key = fs.readFileSync(containerConfig.serverToServerKeyAuth.privateKeyFile, "utf8");

    // path of our request (domain not included)
    var requestPath = "/database/1/" + containerConfig.containerIdentifier + "/development/public/users/current";

    // request body (GET request is blank)
    var requestBody = '';

    // date string without miliseconds
    var requestDate = (new Date).toISOString().replace(/(\.\d\d\d)Z/, "Z");

    var bodyHasher = crypto.createHash('sha256');
    bodyHasher.update(requestBody);
    var hashedBody = bodyHasher.digest("base64");

    var rawPayload = requestDate + ":" + hashedBody + ":" + requestPath;

    // sign payload
    var c = crypto.createSign("sha256");
    c.update(rawPayload);

    var requestSignature = c.sign(key, "base64");

    // put headers together
    var headers = {
        'X-Apple-CloudKit-Request-KeyID': containerConfig.serverToServerKeyAuth.keyID,
        'X-Apple-CloudKit-Request-ISO8601Date': requestDate,
        'X-Apple-CloudKit-Request-SignatureV1': requestSignature
    };

    var options = {
        hostname: 'api.apple-cloudkit.com',
        port: 443,
        path: requestPath,
        method: 'GET',
        headers: headers
    };

    var req = https.request(options, (res) => {
        console.log('statusCode: ', res.statusCode);
        console.log('headers: ', res.headers);

        res.on('data', (d) => {
            process.stdout.write(d);
        });
    });

    req.end();

    req.on('error', (e) => {
        console.error(e);
    });

})();