Client User Identifier

On the client, you can use a User Identifier in two ways.

• Using the device identifier managed internally by the SDK

• Using a custom identifier

Using the Device Identifier Managed Internally by the SDK

Available only for Client-side SDKs.

Client-side SDKs include functionality for managing the device identifier. Therefore, users can be automatically identified without passing a separate User Identifier.

For JavaScript, Android, and iOS, you can obtain the device identifier managed by the SDK — refer to the example code below.

// Variation distribution
const experimentKey = 42
const variation = hackleClient.variation(experimentKey)

// Event tracking
hackleClient.track("purchase")

// Get the internally managed device identifier
const userId = Hackle.getUserId()

// Variation distribution
int experimentKey = 42;
Variation variation = hackleApp.variation(experimentKey);

// Event tracking
hackleApp.track("purchase");

// Get the internally managed device identifier
String deviceId = hackleApp.getDeviceId();

// Variation distribution
let variation = hackleApp.variation(experimentKey: 42)

// Event tracking
hackleApp.track(eventKey: "purchase")

// Get the internally managed device identifier
let deviceId = hackleApp.deviceId

<HackleProvider hackleClient={hackleClient}>
  <YourApp />
</HackleProvider>

Using a Custom Identifier

The SDK identifies users via the identifier passed as a parameter. The identifier you pass can be a Primary Key you manage yourself, a device identifier, a member ID, an email address, a hash value, etc.

// Variation distribution
const experimentKey = 42;
const user = { userId: "ae2182e0" };
const variation = hackleClient.variation(experimentKey, user);

// Event tracking
hackleClient.track("purchase", user);

// Variation distribution
long experimentKey = 42L;
String userId = "ae2182e0";
Variation variation = hackleApp.variation(experimentKey, userId);

// Event tracking
hackleApp.track("purchase", userId);

// Variation distribution
let variation = hackleApp.variation(experimentKey: 42, userId: "ae2182e0")

// Event tracking
hackleApp.track(eventKey: "purchase", userId: "ae2182e0")

const user = { 
    userId: "ae2182e0"
}

<HackleProvider hackleClient={hackleClient} user={user}>
  <YourApp />

Example: Creating a Custom Identifier

If you only need data for logged-in users, you can use the member ID or email address used at login as the identifier.

However, if you need to include non-logged-in users, it is recommended to use a value that can distinguish users based on the app, device, or browser. (For mobile apps, use a UUID or ADID value; for PC/Mobile web, use a cookie value.)

Below is an example of generating a User Identifier based on cookies.

import Cookies from "js-cookie"
import uuid4 from "uuid4"
function getUserId() {
  const key = "PCID" // Enter your preferred name
  const id = Cookies.get(key)
  if (id) {
    return id
  } else {
    const id = uuid4()
    const [top, second] = window.location.hostname.split(".").reverse()
    const domain = `.${second}.${top}`
    Cookies.set(key, id, { expires: 99999, domain: domain, path: "/" })
    return id
  }
}

const app = require("express")()
const bodyParser = require("body-parser")
const cookieParser = require("cookie-parser")
const {v4: uuidv4} = require("uuid")

app.use(bodyParser.urlencoded({extended: false}))
app.use(cookieParser())
app.set("view engine", "ejs")
app.set("views", "views")

function extractDomain(hostname) {
    const DOMAIN_MATCH_REGEX = /[a-z0-9][a-z0-9-]+\.[a-z.]{2,6}$/i;
    const SIMPLE_DOMAIN_MATCH_REGEX = /[a-z0-9][a-z0-9-]*\.[a-z]+$/i;
    let domain_regex = DOMAIN_MATCH_REGEX;
    const parts = hostname.split(".");
    const tld = parts[parts.length - 1];
    if (tld.length > 4 || tld === "com" || tld === "org") {
        domain_regex = SIMPLE_DOMAIN_MATCH_REGEX;
    }
    const matches = hostname.match(domain_regex);
    return matches ? matches[0] : "";
}

app.use((req, res, next) => {
    const domain = extractDomain(req.headers.host)

    if (!req.cookies.deviceId) {
        const deviceId = uuidv4()
        res.cookie("deviceId", deviceId, {
            maxAge: 365 * 10 * 365 * 24 * 60 * 60,
            domain: domain,
            path: "/"
        })
        req.cookies.deviceId = deviceId
    }
    next()
});

app.get("/", (req, res) => {
    console.log(req.cookies.deviceId)
    res.render("index")
});

app.listen(3000, () => {
    console.log("App Start")
});