Typically, when users request the same content over HTTP and HTTPS, the request URLs differ only by protocol, for example, http://domain/index.html and https://domain/index.html. By default, CDN servers cache these as separate objects, and requests using different protocols hit different cache entries, even though the file content is usually identical.

On the Atomile CDN platform, you can customize whether requests that differ only by the HTTP/HTTPS protocol should share the same cached object. You can also configure whether protocol differences should be ignored when purging cache on CDN servers, so that resources with the same URL path but different protocols can be refreshed together.

To improve the cache hit ratio on CDN servers, we strongly recommend enabling HTTPS/HTTP Cache Sharing.

How to Configure HTTPS/HTTP Cache Sharing

1. Log in to the Atomile Console and select the appropriate product.
2. Go to Configuration, locate the domain you want to configure, and click Edit Configuration at the top or the Edit button to the right of the domain.
3. On the configuration page, find HTTPS/HTTP Cache Sharing under Cache Optimization, and click Add.
4. On the rule editing page, configure the following options as needed.

Parameter	Description
Ignore Protocol When Caching	The default value is No, which means the same file requested over HTTP and HTTPS is cached as separate objects on CDN nodes. If you choose Yes, CDN servers ignore the request protocol. Once a file is cached on CDN servers, requests for the same file over either HTTP or HTTPS hit the same cache entry.
Ignore Protocol When Purging	The default value is No, which means that if you submit a cache refresh task for an https:// URL, only the https:// cache entry on CDN servers is refreshed. If an http:// cache entry also exists, requests over HTTP still hit the existing cache. If you choose Yes, the protocol in the refresh task URL is ignored, and both the http:// and https:// cache entries on CDN servers are refreshed. Subsequent requests over either HTTP or HTTPS result in a cache MISS. Currently, this setting applies only to URL Refresh mode.

After completing the configuration, click OK, and then click Next to submit your settings. To minimize potential disruption to your production environment, we strongly recommend performing a Pre-deploy test in a staging environment. This important step ensures that your configuration is correct before it goes live.

After you confirm that the settings are correct, click Deploy Now to apply them in the live environment. The configuration typically takes effect within 3 to 5 minutes. For more information about pre-deployment testing and validation, refer to Deploy the Configurations to Staging Environment for Validation.

Notes

If you set Ignore Protocol When Caching to Yes, then Ignore Protocol When Purging must also be set to Yes and cannot be set to No.

Otherwise, because caching ignores the protocol, user requests over either HTTP or HTTPS may hit the same cached object, but the content may originally have been cached under HTTP. If you then submit a refresh task using an HTTPS URL and protocol is not ignored during cache refresh, the HTTP-related cached object would not be refreshed. As a result, users might still receive stale cached content if it remains within the cache validity period.