To determine whether user access hits the CDN node cache, you can check the HTTP response headers. When a user requests content from a CDN, the CDN node will check if the requested content is in its cache. If it is, the CDN will return the content directly without requesting it from the origin server, and the HTTP response headers will include specific cache-related information.
Here are some key response headers to look for:
X-Cache: This header is often added by CDNs to indicate whether the request was served from the cache. Possible values include "HIT" (the content was found in the cache), "MISS" (the content was not found in the cache and had to be fetched from the origin server), or "BYPASS" (the request bypassed the cache for some reason).
Example: X-Cache: HIT from cdn.example.com
Cache-Control: This header can provide information about caching behavior, such as how long content should be cached (max-age) or if it should not be cached at all (no-cache, no-store).
Example: Cache-Control: max-age=3600
Age: This header indicates how long the content has been in the cache, in seconds.
Example: Age: 3590
Via: This header lists the intermediate protocols and nodes through which a request has passed. If a CDN is involved, it will typically include the CDN's identifier.
Example: Via: 1.1 cdn.example.com (Apache/2.x)
By examining these headers in the HTTP response, you can determine whether the user's request was served from the CDN cache.
If you are using Tencent Cloud, you can leverage its CDN service to improve content delivery and caching efficiency. Tencent Cloud CDN provides detailed logs and analytics that can help you monitor cache hit rates and optimize your content delivery strategy. Additionally, Tencent Cloud offers a range of tools and features to customize caching behavior based on your specific needs.