Extend Cache PDFs
The 'Extend Cache PDFs' filter is enabled by specifying:
pagespeed EnableFilters extend_cache_pdfs;
'Extend Cache PDFs' is a version of Extend
Cache that acts on PDFs. Unlike 'Extend Cache' it applies not only to
resources but also to hyperlinks. For example, while 'Extend Cache' would not
<a href="example.jpg">, 'Extend Cache
PDFs' would apply to
Extend Cache: Operation describes the standard operation of cache extension in PageSpeed. This filter identifies PDF URLs by their ".pdf" extension and marks them as eligible for cache extension.
You can see the filter in action at
In addition to the limitations of Extend Cache, this filter is limited by its reliance on file extensions for identifying potential PDF URLs. PDF resources with URLs ending in something other than ".pdf" won't be considered for cache extension.
This filter has the same risks as Extend Cache.