[TYPO3-core] RFC: Make image hash names longer to avoid collisions

Ernesto Baschny [cron IT] ernst at cron-it.de
Fri May 18 11:56:19 CEST 2007

Ernesto Baschny [cron IT] wrote: on 18.05.2007 11:54:

>> On 18.05.2007, at 10:18, Andreas Otto wrote:
>>> Martin Kutschker wrote:
>>>> I never understood the logic of using truncated md5 hashes and argued
>>>> before to use only the real hashes.
>> I'm all for it.
>>> * Check DB layout: Where are short md5 hashes used?
>> Easy, I can do this. Extensions would probably break, though.
>>> * Check TYPO3core: Where are short md5 hashes used?
>> Doesn't matter that much, see below.
>>> * How to change existing code to make use of full-length md5 hashes? What
>>> about backwards-compatibility?
>> Easy: Just change the default in shortMD5 from 10 to 32, all places
>> should work. The remaining ones should be easy to find. Again, extension
>> could break or at least still use short hashes.
>> Second possibility: Make shortMD5 always return full md5 hash, ignoring
>> the requested length. *Will* break some things. :)
> I won't make "32" the default behaviour of shortMD5, as this would
> probably make more trouble than benefits. I would replace the call to
> t3lib_div::shortMD5($string)
> with something like:
> t3lib_div::shortMD5($string, $TYPO3CONF[...]['shortMD5size'])
> throughout core, and adapt core-tables acordingly, if needed. We could
> then mark shortMD5 as deprecated and make extension developers simply
> use "md5()" in future. As soon as everyone is happy with 32 byte hashes,
> we can drop shortMD5.
> I currently cannot see any reason for 10-char hashes except the "optic"
> in filenames. And if it is just the optic, we can argue with the
> collision problem with that. I don't really care if my temp-file is called:
> stylesheet_124ee84b16.css  or
> stylesheet_124ee84b1640b79e0577c4db69c805a0.css
> Maybe if we have hundrets of temp-images (e.g. GMENU) this will increase
> page-sizes a bit? or make debugging a bit harder?

BTW, this being a discussion, I would propose to follow that up in
typo3-dev list, as other non-core people might have different opinions
on that matter.


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