• websites

Mixing Dynamic and Cached Data

Introduction

This is a sample showing how to integrate product data details such as description, price, availability etc with different data freshness requirements. AMPs can be served from the AMP Cache. Due to the AMP Cache's stale-while-invalide caching strategy, one user will see stale data until the latest version has been fetched. This might be a problem if product data needs always to be up-to-date, for example, product availability. This sample demonstrates one approach how to avoid stale data on cached AMPs.

Setup

We use amp-list for retrieving latest data from the server.

<script async custom-element="amp-list" src="https://cdn.ampproject.org/v0/amp-list-0.1.js"></script>

We use amp-mustache as a templating for amp-list

<script async custom-template="amp-mustache" src="https://cdn.ampproject.org/v0/amp-mustache-0.2.js"></script>

How to implement dynamic and cached product data details

For product details such a description or title, where are unlikely to change frequently, you don't need to do anything special. To ensure that users always see the latest content, you can use the amp-list component which will fetch and render content directly from your server.

<h3>My product</h3>
<p>This is a really great product.</p>
<amp-list height="24"
          layout="fixed-height"
          src="/static/samples/json/product.json"
          binding="no">
  <template type="amp-mustache">
    Price: ${{price}}
  </template>
</amp-list>

if you need to make multiple calls to get all the data, that is not a problem in AMP since if multiple amp-list with the same src are found in the page, only one network call is actually made by the AMP runtime.

By checking the network tab of the Chrome dev console, you can check that this second amp-list does not cause a second network call.

Since we are using a service-worker you may see two similar calls one after the other to the same endpoint, so to better verify this behaviour, go to Application -> Service workers and click on Unregister.

<amp-list height="24"
          layout="fixed-height"
          src="/static/samples/json/product.json"
          binding="no">
  <template type="amp-mustache">
    Availability: {{availability}}
  </template>
</amp-list>

• Written by @kul3r4