Expires Header Treatment

Category: Caching

Purpose: Determines how an edge server will handle the Expires header in the response sent to the client. This feature overrides the Expires header generated by the External Max-Age feature.

The easiest way to achieve this type of configuration is to place the External Max-Age and the Expires Header Treatment features in the same statement.

Value	Result
Pass Through	Ensures that the following actions will take place: Ensures that the Expires header produced by the External Max-Age feature is never added to the response. If the origin server produces an Expires header, it will pass through to the end-user. If the origin server does not set an Expires header, then this mode may cause the response to not include an Expires header.
Overwrite	Ensures that the following actions will take place: Overwrites the Expires header generated by the origin server. Adds the Expires header produced by the External Max-Age feature to the response.
Add if Missing	If an Expires header was not received from the origin server, then this option adds the Expires header produced by the External Max-Age feature. This option is useful for ensuring that all assets will be assigned an Expires header.
Remove	Ensures that an Expires header is not included with the header response. If an Expires header has already been assigned, then it will be stripped from the header response.

Default Behavior: Overwrite