Serving files

Required

• Purge cached copies when a file is deleted or removed

  MED-21

  When a file is deleted, erased or taken down, purge its addresses and every derived file from the CDN in the same job. Close the request only after the purge is confirmed.

Recommended

• Give every file version its own address

  MED-19

  Put a version or a content hash in the address of every public file and derived file. A changed file gets a new address, so each address can be cached as long as a hashed asset.

• Sign CDN access to private media for the whole stream

  MED-20

  Serve private video and other media made of many files through the CDN with a signed cookie or token for one path prefix. The CDN checks it on every segment, and the app checks access before it issues one.

Rules on serving files in other playbooks

• Serve private files through short-lived links signs single downloads and sets Content-Disposition.
• Let large downloads resume with range requests answers 206 for big files.
• Cache files for a year and pages briefly sets the cache lifetimes.
• Stop browsers guessing file types sends nosniff and the right type.
• Keep private pages out of shared caches and Keep unkeyed headers from changing cached pages are the cache attack tests.
• Use a managed DNS and CDN that exports your zone names the delivery network.