Is extend_cache_pdfs enabled by default?

No. extend_cache_pdfs is not in CoreFilters, the default RewriteLevel; it runs only when you enable it by name with EnableFilters.

How do I enable extend_cache_pdfs on Apache and nginx?

Add ModPagespeedEnableFilters extend_cache_pdfs on Apache or pagespeed EnableFilters extend_cache_pdfs; on nginx. On IIS, add pagespeed EnableFilters extend_cache_pdfs to pagespeed.config.

filter · Cache control

Extend cache for PDFs (extend_cache_pdfs)

Category:: Caching
CoreFilters:: No
OptimizeForBandwidth:: No
Risk:: Generally safe

Applies the same content-hash-based cache extension to PDF file links. Enable this filter if your site serves PDFs that change infrequently.

When to use it

Not in CoreFilters: it runs only when you enable it by name.
Risk rating on these docs: Generally safe.

Risks

The Cache control page lists no specific risks for this filter. If a page misbehaves with it, DisableFilters extend_cache_pdfs turns it off for the scope you set it in.

Configuration

Enable it in the module configuration, at server, virtual-host or location scope:

Apache

ModPagespeedEnableFilters extend_cache_pdfs

nginx

pagespeed EnableFilters extend_cache_pdfs;

IIS (pagespeed.config)

pagespeed EnableFilters extend_cache_pdfs

On the worker

The worker runs its own pipeline, configured by flags. Its equivalent of this filter is the cache extension transform. Always-on under pagespeed on;.

Scoping, ForbidFilters and the thresholds filters read: Choosing filters .

Live example

Applies cache extension to linked PDF files.

This filter changes how the page is structured or delivered, not its size, so the example shows a source diff rather than a byte or request reduction.

See the before and after, with the source diff →

Frequently asked questions

What does the extend_cache_pdfs filter do?: Applies the same content-hash-based cache extension to PDF file links. Enable this filter if your site serves PDFs that change infrequently.
Is extend_cache_pdfs enabled by default?: No. extend_cache_pdfs is not in CoreFilters, the default RewriteLevel; it runs only when you enable it by name with EnableFilters.
How do I enable extend_cache_pdfs on Apache and nginx?: Add ModPagespeedEnableFilters extend_cache_pdfs on Apache or pagespeed EnableFilters extend_cache_pdfs; on nginx. On IIS, add pagespeed EnableFilters extend_cache_pdfs to pagespeed.config.

local_storage_cache — Local storage cache
rewrite_domains — Rewrite domains
extend_cache — Extend cache

This page is drawn from the extend_cache_pdfs entry on Cache control. Every filter in one table: PageSpeed filters.