Prefetch content

Use cases

• Promotional activities

  Prefetch static resources for a campaign page to ESA POPs before launch. After the event starts, requests for these resources are served from the edge.

• Installation package releases

  Prefetch installation or upgrade packages to ESA POPs before release. After launch, downloads are served from the ESA POP, increasing speed and reducing origin load.

Prefetch methods

ESA supports two prefetch methods: Instant Prefetch and Scheduled Prefetch.

• Instant Prefetch: Starts as soon as you submit URLs, quickly caching resources on ESA POPs.

• Scheduled Prefetch: Starts at a specified time with configurable frequency. Helps avoid peak hours and control origin traffic from prefetching.

Notes

• When you submit a prefetch task, ESA POPs fetch resources directly from your origin. Submitting many tasks at once spikes origin bandwidth and load. Use scheduled prefetch to spread the load.

• A prefetch task typically takes 5 to 30 minutes. Smaller files are prefetched faster.

• By default, prefetch requests include the Accept-Encoding:gzip header. To add custom headers or prefetch multiple replicas, use the PreloadCaches API and set the Header parameter.

• Prefetch does not follow 301/302 redirects. If your origin returns a redirect, the task fails. To handle redirects, contact us to enable the 301/302 redirect for origin fetch feature.

• If a prefetch URL contains non-ASCII characters (spaces, Chinese characters, or special characters), encode the URL before submission. Otherwise the system cannot process the task.

• If the Multi-level cache feature is configured for the edge caching layer, the prefetch cache feature does not work.

• If you have set the Rewrite URL feature, use the rewritten URL for prefetch tasks.

Procedure

1. In the ESA console, choose Websites, and click the target site in the Website column.

2. In the navigation pane on the left, choose Caching > Prefetch Cache.

3. Select a prefetch method. ESA supports two methods: Instant Prefetch and Scheduled Prefetch.

   Immediate prefetch

   An immediate prefetch task starts as soon as you submit the URLs to quickly cache the resources on ESA POPs.

   You can use two input methods: Manual Input and Upload File.

   Input method	Description
   Manual Input	Enter URLs in the input box and click Submit. Specify the full path for each file, one URL per line (up to 100). For example: https://www.example.com/cat.jpg https://www.example.com/image/cat.jpg
   Upload File	For bulk prefetch, add URLs to a .txt file (one URL per line, full path required) and upload it. Maximum file size: 10 MB.

   Scheduled prefetch

   A scheduled prefetch task starts at a specified time. You can also specify the prefetch frequency. This helps you avoid peak business hours, control the back-to-origin traffic generated by prefetching, and reduce the load on your origin server.

   1. Add URLs to a .txt file (one URL per line, full path required). Maximum file size: 10 MB.

   2. Click Create Prefetch Task.

   3. Enter a custom name for the prefetch task, upload the file, and click Next.

      Note

      You can create up to 100 prefetch tasks.

      

   4. Configure the prefetch schedule: time period, submission interval (minimum 1 second), and batch size (up to 100 URLs per batch).

      Note

      The total number of prefetch schedules cannot exceed 10.

      

   5. Click OK.

4. View the prefetch progress.

   After submission, view task records and progress on the Prefetch Records tab. 100% indicates completion. Large batches may slow progress.

Availability