Bug #84562


FE output compressed twice if zlib.output_compression and [FE][compressionLevel] is enabled and backend session exists

Added by Hendrik Becker about 6 years ago. Updated over 4 years ago.

Should have
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This was tested on TYPO3 7.6 as well as 6.2 and produces the same results.

If I activate [FE][compressionLevel] in TYPO3 install tool (e.g. set it to 5)
and activate zlib.output_compression in php.ini (e.g. set it to 16384)
and log-in into the TYPO3 backend as admin, then previewing the frontend shows binary (compressed) data.

This is actually reasonable, because first TYPO3 compresses the output and in addition PHP does it again.

But the thing is, this does not happen, if I have no backend session.
If I browse the frontend without backend session, everything works fine.
A congruent behaviour would be nice here.

If I disable the TYPO3 [FE][compressionLevel] and leave the PHP zlib.output_compression enabled, I have the problem, that TYPO3 does not generate compressed CSS and JS files anymore.
It would be awesome, if I had the option to enable / disable TYPO3 FE output compression selectively or if TYPO3 skips the FE output compression if zlib.output_compression is enabled.
That way I could use zlib.output_compression (for TYPO3 and other PHP applications on the same vhost) in combination with TYPO3 generated compressed CSS and JS files.

I prefer zlib.output_compression because of the PHP documentation:
"... note that using zlib.output_compression is preferred over ob_gzhandler()"

My current workaround is:
I disabled the zlib.output_compression in php.ini to fix the symptoms.
In addition I activated in apache and added output filtering to compress other applications' outputs.

Actions #1

Updated by Gerrit Code Review about 6 years ago

  • Status changed from New to Under Review

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at

Actions #2

Updated by Susanne Moog about 5 years ago

  • Status changed from Under Review to New

Patch had wrong issue number.

Actions #3

Updated by Benni Mack about 5 years ago

  • Status changed from New to Needs Feedback

Hi Hendrik,

we've solved this in TYPO3 v9 via HTTP middlewares (PSR-15) which are different to Backend and FE - can you recheck please?


Actions #4

Updated by Riccardo De Contardi over 4 years ago

  • Status changed from Needs Feedback to Closed

No feedback since the last 90 days => closing this issue.

If you think that this is the wrong decision or experience the issue again and have more information about how to reproduce your problem, please reopen it or ping me.

Thank you and best regards


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