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

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Level 1

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

1 Accepted Solution

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Correct answer by
Employee Advisor

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

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5 Replies

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Level 10

Make sure that Last-Modified header is allowed by the /clientheaders section of the dispatcher farm.

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Administrator

Jörg Hoh​ Can you please look at this one?



Kautuk Sahni

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Correct answer by
Employee Advisor

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

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Level 1

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

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Level 2

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.