Which header is required for a response to be cached by Cloud CDN?

For a response to be cached by Cloud CDN, it is essential to include the Cache-Control: public header. This header signifies that the response can be stored by any cache, including browsers and the Cloud CDN itself. By using Cache-Control: public, you are explicitly stating that the content is not sensitive and is suitable for caching, allowing it to be served quickly to users from the nearest cache location.

Other headers such as Cache-Control: no-store instruct the systems not to cache the response at all, which would prevent caching and defeat the purpose of using a Content Delivery Network (CDN) like Cloud CDN. The Content-Length header provides information about the size of the response body but does not influence caching behavior. Similarly, Content-Encoding pertains to how the response data is compressed or encoded, which also does not affect whether the response can be cached. Therefore, using Cache-Control: public is the necessary and correct choice for enabling response caching in Cloud CDN.