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Setup Next.js Website with Personalize - Vercel

This guide will help you setup your Next.js website with Personalize, hosted on Vercel.

Prerequisites

  • Next.js website on the latest version (14 and above) with app router
  • Website content sourced from a Stack
  • Website deployed on Vercel
  • Personalize project created and connected to the Stack

Steps for Execution

To set up your Next.js website with Personalize, perform the following steps:

Get Personalize Project UID

To retrieve the project UID, perform the steps given below:

  1. Navigate to Personalize > your preferred project.
  2. Click the Settings icon in the left navigation panel.
  3. In the General tab, under Project Details, you will find the 24-character project UID.Setup-Nextjs-Website-Vercel-Project-Details
  4. Click the Copy icon to copy the project UID to your clipboard. We will need this UID while setting up the Personalize Edge SDK in the next step.

Proxy Requests with Middleware

Middleware allows you to execute logic on the edge before each request on the website. Using this feature, we can make a call to the Personalize Edge API and fetch the Manifest for each visitor. The Manifest contains the selected Variant for each Experience. We can then pass these variants as the URL query parameters.

Let’s take a look at each one of these steps.

  1. Install the Personalize SDK

    To install the Personalize Edge SDK in your Next.js project:

    $ npm install @contentstack/personalize-edge-sdk

    Additional Resource: The API Reference for the SDK contains a lot of information on how to use the SDK.

  2. Create the Middleware Handler

    The middleware.ts is to be created at the root folder of your website source code. To create the Middleware Handler:

    // middleware.ts
export default async function middleware(req: NextRequest) {
  return NextResponse.next();
}

    The Middleware will now allow you to proxy all requests.

  3. Initialize the SDK

    Now modify the middleware.ts file with the following code to initialize the Personalize Edge SDK:

    import {
  NextRequest,
  NextResponse,
} from 'next/server';
import Personalize from '@contentstack/personalize-edge-sdk';
export default async function middleware(req: NextRequest) {
  const projectUid = process.env.NEXT_PUBLIC_PERSONALIZATION_PROJECT_UID as string;
  // set a custom edge API URL
  if (process.env.CONTENTSTACK_PERSONALIZE_EDGE_API_URL) {
  Personalize.setEdgeApiUrl(process.env.CONTENTSTACK_PERSONALIZE_EDGE_API_URL);
  }
  // Initialize the SDK and pass the request as well
  await Personalize.init(projectUid, {
    request: req,
  });
  return NextResponse.next();
}

    Here, we initialize the Personalize Edge SDK. Notice how we are passing the request object along. As part of the initialization process, the user context is extracted from the request object and used to fetch the User Manifest from the Personalize Edge API. The Manifest provides a list of variants selected in each published experience.

    Note: You can also provide a different Edge API URL in case you are on a different Contentstack region. Here are the Edge API URLs for each region:

    • AWS NA: https://personalize-edge.contentstack.com
    • AWS EU: https://eu-personalize-edge.contentstack.com
    • Azure NA: https://azure-na-personalize-edge.contentstack.com
    • Azure EU: https://azure-eu-personalize-edge.contentstack.com
    • GCP NA: https://gcp-na-personalize-edge.contentstack.com

  4. Pass the variant parameter in the URL

    Now add the following code the middleware.ts file to pass the variant parameter in the URL:

    import {
  NextRequest,
  NextResponse,
} from 'next/server';
import Personalize from '@contentstack/personalize-edge-sdk';
export default async function middleware(req: NextRequest) {
  const projectUid = process.env.NEXT_PUBLIC_PERSONALIZATION_PROJECT_UID as string;
  if (process.env.CONTENTSTACK_PERSONALIZE_EDGE_API_URL) {
  Personalize.setEdgeApiUrl(process.env.CONTENTSTACK_PERSONALIZE_EDGE_API_URL);
  }
  await Personalize.init(projectUid, {
    request: req,
  });
  // get the variant parameter from the SDK
  const variantParam = Personalize.getVariantParam();
  const parsedUrl = new URL(req.url);
  // set the variant parameter as a query param in the URL
  parsedUrl.searchParams.set(Personalize.VARIANT_QUERY_PARAM, variantParam);
  // rewrite the request with the modified URL
  const response = NextResponse.rewrite(parsedUrl);
  return response;
}

    Here, we’re passing the variants we receive from Personalize into a query parameter personalize_variants as defined by Personalize.VARIANT_QUERY_PARAM. We then make a request to the Next.js app with the modified URL. Essentially, we are rewriting the URL with the modified query parameter (here the website user does not know about the changed URL).

    For e.g. if we have a URL as follows: /rewards, we’re rewriting it to /rewards?personalize_variants=0_0,1_0 here 0_0,1_0 is the variant parameter which is the combination of the Experience Short UID mapped to the selected Variant Short UID.

    We use the short uids here to optimize the URL length which has a limit.

  5. Add Response Context

    Now add the following code to the middleware.ts file to add the response context:

    import {
  NextRequest,
  NextResponse,
} from 'next/server';
import Personalize from '@contentstack/personalize-edge-sdk';
export default async function middleware(req: NextRequest) {
  const projectUid = process.env.NEXT_PUBLIC_PERSONALIZATION_PROJECT_UID as string;
  
  if (process.env.CONTENTSTACK_PERSONALIZE_EDGE_API_URL) {
  Personalize.setEdgeApiUrl(process.env.CONTENTSTACK_PERSONALIZE_EDGE_API_URL);
  }
  
  await Personalize.init(projectUid, {
    request: req,
  });
  
  // get the variant parameter from the SDK
  const variantParam = Personalize.getVariantParam();
  const parsedUrl = new URL(req.url);
  
  // set the variant parameter as a query param in the URL
  parsedUrl.searchParams.set(Personalize.VARIANT_QUERY_PARAM, variantParam);
  
  // rewrite the request with the modified URL
  const response = NextResponse.rewrite(parsedUrl);
  
  // add cookies to the response
  await Personalize.addStateToResponse(response);
  
  return response;
}

    The Personalize Edge SDK needs to identify the visitor on the next request. To achieve this, the SDK sets two cookies on the response, with one for the user UID and another for the current state of the manifest. Here, we use addStateToResponse() method to modify the response object and add those cookies before returning it.

    We now have the Middleware ready to go. Next, we’ll look at leveraging the variant parameter passed in the URL.

Fetching Variant Content from Origin

The final step is to fetch the variant content using the variant parameter passed in the URL. This step needs to be performed for all the pages that need Personalize enabled.

In the following example, we are modifying the Homepage (/app/page.ts). Similarly add the code to the other pages of your website source code.

Fetch Personalized Variants from the CMS

Here, we modify the Homepage (/app/page.ts) to fetch Personalized variants from the CMS.

import Personalize from '@contentstack/personalize-edge-sdk';
import contentstack from '@contentstack/delivery-sdk';
const Page = async ({
  searchParams,
}: {
  searchParams: Record<string,string>;
}) => {
  // extract the variant parameter from the URL
  let variantParam = decodeURIComponent(
    searchParams[Personalize.VARIANT_QUERY_PARAM]
  );
  // initialize the CMS Delivery SDK
  const stack = contentstack.stack({
    apiKey: process.env.NEXT_PUBLIC_CONTENTSTACK_API_KEY,
    deliveryToken: process.env.NEXT_PUBLIC_CONTENTSTACK_DELIVERY_TOKEN,
    environment: process.env.NEXT_PUBLIC_CONTENTSTACK_ENVIRONMENT,
    host: process.env.CONTENTSTACK_DELIVERY_API_HOST,
  });
  // the call to fetch a specific entry
  const entryCall = stack
    .contentType(process.env.NEXT_PUBLIC_CONTENTSTACK_HOMEPAGE_CONTENTTYPE_UID)
    .entry(process.env.NEXT_PUBLIC_CONTENTSTACK_HOMEPAGE_ENTRY_UID);
  let entry;
  if (variantParam) {
    // convert the variant parameter to variant aliases
    const variantAlias = Personalize.variantParamToVariantAliases(variantParam).join(',');
    // pass the variant aliases when fetching the entry
    entry = await entryCall.variants(variantAlias).fetch();
  } else {
    // fetch the entry without the variant aliases
    entry = await entryCall.fetch();
  }
  // render the page with the entry
};

The above example shows how to fetch an entry variant instead of the base entry when variants are passed in the URL. We are converting the variant parameter passed in the URL to variant aliases used in the SDK.

Setting Attributes and Triggering Events

Setting attributes and triggering events can be done in the following ways:

  1. Integrating with a CDP
  2. Using Google Tag Manager
  3. Using the SDK in the code (JavaScript Personalize Edge SDK)

Below we have elaborated on the third approach.

  1. Initialize the SDK

    You can create a personalized React Context to initialize the SDK as follows:

    Note: For this step, we have placed the file in /components/context/ but you can choose to place this wherever appropriate.

    // /components/context/PersonalizeContext.ts
import { createContext } from 'react';
import Personalize from '@contentstack/personalize-edge-sdk';
Personalize.setEdgeApiUrl(process.env.NEXT_PUBLIC_CONTENTSTACK_PERSONALIZE_EDGE_API_URL as string);
Personalize.init(process.env.NEXT_PUBLIC_PERSONALIZATION_PROJECT_UID as string);
export const PersonalizeContext = createContext(Personalize);

    Here, we initialize the Personalize SDK as part of the React Context. We then use the SDK object to create the context.

    The SDK needs to be initialized before setting attributes or triggering events.

    We use React Context here so the SDK is initialized once and then available as Context for any Client Component in Next.js. Setting attributes and triggering impressions and events should be done on the client side since we set data and trigger the events when the page renders on the browser.

  2. Set Attributes

    The following snippet shows how to set an attribute submitted via a form for a user’s age:

    'use client';
import { useContext } from 'react';
import { PersonalizeContext } from '../context/PersonalizeContext';
const Page = () => {
  const Personalize = useContext(PersonalizeContext);
  const onFormSubmit = async (form: MyForm) => {
    await Personalize.set({ age: form.age });
  }
  // render the component
}

    Here, the attributes are a key-value object passed to the set method. You can pass multiple key-values here. If the same key is passed, the existing attribute is overwritten.

  3. Trigger Events

    Impressions

    To let Personalize know that a particular experience is being shown to the user, you can trigger an impression event. The following snippet shows how to trigger impressions:

    'use client';
import { useContext, useEffect } from 'react';
import { PersonalizeContext } from '../context/PersonalizeContext';
const Page = () => {
  const Personalize = useContext(PersonalizeContext);
  useEffect(async () => {
    await Personalize.triggerImpression(MY_EXPERIENCE_SHORT_UID);
  }, []);
  // render the component
}

    We are using useEffect in this example so that the impression is triggered only on the first render of the component, that is, when the page loads for the first time in the browser.

    Here the triggerImpression method takes an Experience Short UID, which you can find in the Personalize UI on the Experiences List page. The SDK will also automatically pass the selected variant of the experience as part of the impression.

    Conversions

    Any action performed by the user can be a conversion event if it leads to a positive outcome. To let Personalize know that an action has been performed, trigger the event as follows:

    'use client';
import { useContext } from 'react';
import { PersonalizeContext } from '../context/PersonalizeContext';
const Page = () => {
  const Personalize = useContext(PersonalizeContext);
  const onClickLearnMore = async (e: any) => {
    e.preventDefault();
    await Personalize.triggerEvent('learnMoreClicked'); // here 'learnMoreClicked' is the eventKey
  }
  // render the component
}

    Here, we are triggering an event on the click of the Learn More button. The triggerEvent method takes an eventKey. The eventKey is configured when you create an event.

    Your Personalize Edge SDK is now set up and ready to interact with your Contentstack Personalize project and proceed with personalization for your website.

Reference Project

You can refer to the following project for a reference implementation: Next.js example GitHub repository and find it hosted here: https://personalize-demo.vercel.app/

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