Purge by Content Tag!

Blog Post created by bmertens on Jun 16, 2017

To improve the flexibility of Smart Purge we have recently added support for purging by content tag.  Content is tagged by the origin using an extra HTTP reply header. Purge requests can be submitted targeting content with individual tags.

  • Header value may have multiple tags separated by commas
  • When EdgePrism receives a new content tag, it will parse and normalize it


For example, given an HTTP response:

HTTP/1.1 200 OK
Cache-Tag: images, css,
Cache-Tag: mytag,,,

 EdgePrism will associate the following normalized content tag with the cached object:



If desired the header name can be changed.  Only 1 header name can be used per configuration. The default maximum content tag size is 64 bytes.  Any tags going beyond the 64 bytes will be ignored.