downstreamCache

Delivery Manager name: Downstream Cacheability
Behavior version: The latest rule format supports the downstreamCache behavior v1.2.

Specify the caching instructions the edge server sends to the end user's client or client proxies. By default, the cache's duration is whichever is less: the remaining lifetime of the edge cache, or what the origin's header specifies. If the origin is set to no-store or bypass-cache, edge servers send cache-busting headers downstream to prevent downstream caching.

Option	Type	Description	Requires
`behavior`	enum	Specify the caching instructions the edge server sends to the end user's client.		{"displayType":"enum","options":["ALLOW","MUST_REVALIDATE","BUST","TUNNEL_ORIGIN","NONE"],"tag":"select"}
	`ALLOW`	The value of `allowBehavior` chooses the caching method and headers to send to the client.
	`MUST_REVALIDATE`	This equates to a `Cache-Control: no-cache` header, which allows caching but forces the client browser to send an `if-modified-since` request each time it requests the object.
	`BUST`	Sends cache-busting headers downstream.
	`TUNNEL_ORIGIN`	This passes `Cache-Control` and `Expires` headers from the origin to the downstream client.
	`NONE`	Don't send any caching headers. Allow client browsers to cache content according to their own default settings.
`allowBehavior`	enum	Specify how the edge server calculates the downstream cache by setting the value of the `Expires` header.	`behavior` is `ALLOW`	{"displayType":"enum","options":["LESSER","GREATER","REMAINING_LIFETIME","FROM_MAX_AGE","FROM_VALUE","PASS_ORIGIN"],"tag":"select"} {"if":{"attribute":"behavior","op":"eq","value":"ALLOW"}}
	`LESSER`	Sends the lesser value of what the origin specifies and the edge cache's remaining duration. This is the default behavior.
	`GREATER`	Sends the greater value of what the origin specifies and the edge cache's remaining duration.
	`REMAINING_LIFETIME`	Sends the value of the edge cache's remaining duration, without comparing it to the origin's headers.
	`FROM_MAX_AGE`	Sends the `cache:max-age` value applied to the object, without evaluating the cache's duration.
	`FROM_VALUE`	Sends the value of the edge cache's duration.
	`PASS_ORIGIN`	Sends the value of the origin's header, without evaluating the edge cache's duration.
`ttl`	string (duration)	Sets the duration of the cache. Setting the value to `0` equates to a `no-cache` header that forces revalidation.	`allowBehavior` is `FROM_VALUE`	{"displayType":"string","tag":"input","type":"text"} {"if":{"attribute":"allowBehavior","op":"eq","value":"FROM_VALUE"}}
`sendHeaders`	enum	Specifies the HTTP headers to include in the response to the client.	`behavior` is `ALLOW`	{"displayType":"enum","options":["CACHE_CONTROL_AND_EXPIRES","CACHE_CONTROL","EXPIRES","PASS_ORIGIN"],"tag":"select"} {"if":{"attribute":"behavior","op":"eq","value":"ALLOW"}}
	`CACHE_CONTROL_AND_EXPIRES`	Sends both `Cache-Control` and `Expires` header.
	`CACHE_CONTROL`	Sends only the origin's `Cache-Control` header.
	`EXPIRES`	Sends only the origin's `Expires` header.
	`PASS_ORIGIN`	Sends the same set of `Cache-Control` and `Expires` headers received from the origin.
`sendPrivate`	boolean	Adds a `Cache-Control: private` header to prevent objects from being cached in a shared caching proxy.	`behavior` is either: `ALLOW`, `MUST_REVALIDATE` AND `sendHeaders` is not `EXPIRES`	{"displayType":"boolean","tag":"input","type":"checkbox"} {"if":{"op":"and","params":[{"attribute":"behavior","op":"in","value":["ALLOW","MUST_REVALIDATE"]},{"attribute":"sendHeaders","op":"neq","value":"EXPIRES"}]}}