tencent cloud

Feature Overview

By configuring the browser cache validity, you can customize client browser cache policies to reduce origin-pull rate.

Note：

When a request comes, if the requested resource is cached on the browser, it will be returned directly. If no, the request will be forwarded to CDN cache nodes. If the resource still cannot be found on the cache node, the request will be forwarded to the origin server.

Configuration Guide

Viewing the configuration

Log in to the CDN console, select Domain Management on the left sidebar, click Manage on the right of a domain name to enter its configuration page. Open the Cache Configuration tab to find the Browser Cache Validity Configuration section.

Adding rules

Click Add Rule to add browser cache validity rules for specified file type, file directory, file path, and homepage.

• Follow origin server: follow the Cache-Control header of the origin server. If the origin server does not have a CC header or its CC header is no-cache/no-store/private, the browser will not cache resources.
• Cache: if the CC header of the origin server is not no-cache/no-store/private, the browser cache validity rules will be applied; otherwise, the browser will not cache resources.
• No cache: no resource is cached in a browser.

Configuration limitations

• Each domain name can have up to 20 rules. Only one "All Files" and "Homepage" rule can be added.
• You can adjust the priority for multiple rules. Rules at the bottom of the list have higher priority.
• In each rule of specified file type, file directory, and file path, up to 50 groups of content can be entered. Please use ";" to separate different content, e.g., Specified File Type: jpg;png.
• Chinese characters are not supported.

Default policies

If no rule is configured or matches requests, the default policies will be applied:

• When a user makes a request for a certain business resource, if the HTTP response header of the origin server contains the field Cache-Control, the Cache-Control will be followed.
• If the HTTP response header of the origin server does not contain the field Cache-Control, then the resource cache validity on the browser will be 600 seconds.

When there are node cache validity rules configured (configuration guide: Node Cache Validity Configuration (New)) or matched:

• If the HTTP response header of the origin server does not contain the field Cache-Control, then the browser will not cache resources.
• If the HTTP response header of the origin server contains the field Cache-Control, then the browser cache will follow Cache-Control.