beresp.stale_while_revalidate
RTIME, can be read and set
, but not unset
.
Available infetch
Same as beresp.stale_if_error
except controls the maximum stale age for
stale while revalidate functionality.
Note that if an object's TTL has expired and it is eligible to be served stale
and to be served stale while revalidating, stale while revalidate takes
precedence. By default the value of beresp.stale_while_revalidate
will be
parsed from the stale-while-revalidate
value in the Surrogate-Control
or
Cache-Control
headers received from the backend.
Try it out
beresp.stale_while_revalidate
is used in the following code examples. Examples apply VCL to real-world use cases and can be deployed as they are, or adapted for your own service. See the full list of code examples for more inspiration.
Click RUN on a sample below to provision a Fastly service, execute the code on Fastly, and see how the function behaves.
Serve stale content from cache while origins are offline
Deal with all potential scenarios for using stale content to satisfy requests when origin is unhealthy or misbehaving.