Dispatcher is not forwarding Last-Modified header when caching is disabled

Forum|Forum|8 years ago
November 22, 2017
5 replies
2738 views

In our setup Dispatcher is not used for caching - this is done by Varnish that sits in front of Dispatcher.

For cache invalidation we need the Last-Modified header that is returned by AEM Publisher, but Dispatcher is removing the header line.

Is there a way to instruct Dispatcher to just forward the Last-Modifed header that is returned by AEM Publisher?

thx Michael

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Best answer by joerghoh

When the file is deliverd out of the dispatcher cache without the header-caching being active, the last-modification time is taken from the mtime of the cache file.

To get the mtime of the AEM publish instance, enable dispatcher header caching; yesterday there was a AEM Gems session on dispatcher where it was mentioned. I hope that Dispatcher - New features and best practices will be updated today.

Jörg

15473203

New Participant

I'm having a similar issue. I'm using Dispatcher 4.2.3 and caching the response headers, but when a cached dam asset is returned, the cached header value is not used, the last modified time of the actual cached file is still used. Any ideas? /clientheaders allows all headers.

schwabixAuthor

New Participant

Thank you for your answers, but our issue was with uncached urls, so activating header caching was not feasible.

This was actually a known issue with Dispatcher 4.2.2 - Daycare support just send me info on this.

DISP-676 - Dispatcher removes Last-Modified header for uncached requests

They also provided a pre-release version of Dispatcher 4.2.3 that solves our issue.

Thx again for warm welcome on this forum

Best regards

Michael

joerghohAccepted solution

Employee

When the file is deliverd out of the dispatcher cache without the header-caching being active, the last-modification time is taken from the mtime of the cache file.

To get the mtime of the AEM publish instance, enable dispatcher header caching; yesterday there was a AEM Gems session on dispatcher where it was mentioned. I hope that Dispatcher - New features and best practices will be updated today.

Jörg